diff --git a/packages/evm/package.json b/packages/evm/package.json
index 2882df1..f6ec21b 100644
--- a/packages/evm/package.json
+++ b/packages/evm/package.json
@@ -22,7 +22,8 @@
   },
   "dependencies": {
     "@types/bn.js": "^4.11.5",
-    "bn.js": "^5.1.1"
+    "bn.js": "^5.1.1",
+    "js-sha3": "^0.8.0"
   },
   "devDependencies": {
     "@types/chai": "^4.2.7",
diff --git a/packages/evm/src/evm/Address.ts b/packages/evm/src/Address.ts
similarity index 100%
rename from packages/evm/src/evm/Address.ts
rename to packages/evm/src/Address.ts
diff --git a/packages/evm/src/evm/Byte.ts b/packages/evm/src/Byte.ts
similarity index 100%
rename from packages/evm/src/evm/Byte.ts
rename to packages/evm/src/Byte.ts
diff --git a/packages/evm/src/evm/Bytes32.ts b/packages/evm/src/Bytes32.ts
similarity index 100%
rename from packages/evm/src/evm/Bytes32.ts
rename to packages/evm/src/Bytes32.ts
diff --git a/packages/evm/src/evm/ExecutionContext.ts b/packages/evm/src/ExecutionContext.ts
similarity index 71%
rename from packages/evm/src/evm/ExecutionContext.ts
rename to packages/evm/src/ExecutionContext.ts
index 2d47bdf..c57eac2 100644
--- a/packages/evm/src/evm/ExecutionContext.ts
+++ b/packages/evm/src/ExecutionContext.ts
@@ -1,6 +1,6 @@
 import { Stack } from './Stack'
 import { OutOfGas } from './errors'
-import { Memory, GasAwareMemory } from './Memory'
+import { Memory } from './Memory'
 import { State } from './State'
 import { Byte } from './Byte'
 import { Message } from './Message'
@@ -10,8 +10,7 @@ import { parseBytecode } from './parseBytecode'
 export class ExecutionContext {
   code: Opcode[]
   stack = new Stack()
-  memory: GasAwareMemory
-  state: State
+  memory: Memory
   returnValue?: Byte[]
   reverted = false
   programCounter = 0
@@ -19,13 +18,9 @@ export class ExecutionContext {
   private _gasUsed = 0
   private _gasRefund = 0
 
-  constructor (public message: Message) {
-    this.state = message.state.clone()
+  constructor (public message: Message, public state: State) {
     this.code = parseBytecode(message.code)
-    this.memory = new GasAwareMemory(
-      new Memory(),
-      this.useGas.bind(this),
-    )
+    this.memory = new Memory(this.useGas.bind(this))
   }
 
   get gasUsed () {
@@ -40,10 +35,6 @@ export class ExecutionContext {
     }
   }
 
-  useRemainingGas () {
-    this._gasUsed = this.message.gasLimit
-  }
-
   get gasRefund () {
     return this._gasRefund
   }
diff --git a/packages/evm/src/ExecutionResult.ts b/packages/evm/src/ExecutionResult.ts
new file mode 100644
index 0000000..9033ede
--- /dev/null
+++ b/packages/evm/src/ExecutionResult.ts
@@ -0,0 +1,27 @@
+import { State } from './State'
+import { Byte } from './Byte'
+import { VMError } from './errors'
+
+export type ExecutionResult =
+  | ExecutionSuccess
+  | ExecutionRevert
+  | ExecutionError
+
+export interface ExecutionSuccess {
+  type: 'ExecutionSuccess',
+  state: State,
+  gasUsed: number,
+  gasRefund: number,
+  returnValue: Byte[],
+}
+
+export interface ExecutionRevert {
+  type: 'ExecutionRevert',
+  gasUsed: number,
+  returnValue: Byte[],
+}
+
+export interface ExecutionError {
+  type: 'ExecutionError',
+  error: VMError,
+}
diff --git a/packages/evm/src/evm/Memory.ts b/packages/evm/src/Memory.ts
similarity index 72%
rename from packages/evm/src/evm/Memory.ts
rename to packages/evm/src/Memory.ts
index cbab27f..f02d545 100644
--- a/packages/evm/src/evm/Memory.ts
+++ b/packages/evm/src/Memory.ts
@@ -1,20 +1,38 @@
 import { GasCost } from './opcodes'
 import { Byte } from './Byte'
 
-export interface IMemory {
-  getSize (): number,
-  getBytes (offset: number, length: number): Byte[],
-  setBytes (offset: number, bytes: Byte[]): void,
-}
+export class Memory {
+  private items: Byte[] = []
+  private memoryUsed = 0
+  private gasUsed = 0
 
-export class GasAwareMemory implements IMemory {
   constructor (
-    public memory: Memory,
     private useGas: (gas: number) => void,
   ) {}
 
-  private memoryUsed = 0
-  private gasUsed = 0
+  getSize () {
+    return this.items.length
+  }
+
+  getBytes (offset: number, length: number) {
+    this.onMemoryAccess(offset, length)
+    if (length === 0) {
+      return []
+    }
+    this.expand(offset + length)
+    return this.items.slice(offset, offset + length)
+  }
+
+  setBytes (offset: number, bytes: Byte[]) {
+    this.onMemoryAccess(offset, bytes.length)
+    if (bytes.length === 0) {
+      return
+    }
+    this.expand(offset + bytes.length)
+    for (let i = 0; i < bytes.length; i++) {
+      this.items[offset + i] = bytes[i]
+    }
+  }
 
   private onMemoryAccess (offset: number, length: number) {
     if (length === 0) {
@@ -31,50 +49,10 @@ export class GasAwareMemory implements IMemory {
     }
   }
 
-  getSize () {
-    return this.memory.getSize()
-  }
-
-  getBytes (offset: number, length: number) {
-    this.onMemoryAccess(offset, length)
-    return this.memory.getBytes(offset, length)
-  }
-
-  setBytes (offset: number, bytes: Byte[]) {
-    this.onMemoryAccess(offset, bytes.length)
-    this.memory.setBytes(offset, bytes)
-  }
-}
-
-export class Memory implements IMemory {
-  private items: Byte[] = []
-
   private expand (targetSize: number) {
     const targetLength = 32 * Math.ceil(targetSize / 32)
     for (let i = this.items.length; i < targetLength; i++) {
       this.items[i] = 0 as Byte
     }
   }
-
-  getSize () {
-    return this.items.length
-  }
-
-  getBytes (offset: number, length: number) {
-    if (length === 0) {
-      return []
-    }
-    this.expand(offset + length)
-    return this.items.slice(offset, offset + length)
-  }
-
-  setBytes (offset: number, bytes: Byte[]) {
-    if (bytes.length === 0) {
-      return
-    }
-    this.expand(offset + bytes.length)
-    for (let i = 0; i < bytes.length; i++) {
-      this.items[offset + i] = bytes[i]
-    }
-  }
 }
diff --git a/packages/evm/src/Message.ts b/packages/evm/src/Message.ts
new file mode 100644
index 0000000..6d63087
--- /dev/null
+++ b/packages/evm/src/Message.ts
@@ -0,0 +1,16 @@
+import { Address } from './Address'
+import { Bytes32 } from './Bytes32'
+import { Byte } from './Byte'
+
+export interface Message {
+  readonly account: Address,
+  readonly code: readonly Byte[],
+  readonly data: readonly Byte[],
+  readonly origin: Address,
+  readonly sender: Address,
+  readonly gasLimit: number,
+  readonly gasPrice: Bytes32,
+  readonly value: Bytes32,
+  readonly enableStateModifications: boolean,
+  readonly callDepth: number,
+}
diff --git a/packages/evm/src/evm/Stack.ts b/packages/evm/src/Stack.ts
similarity index 100%
rename from packages/evm/src/evm/Stack.ts
rename to packages/evm/src/Stack.ts
diff --git a/packages/evm/src/evm/State.ts b/packages/evm/src/State.ts
similarity index 100%
rename from packages/evm/src/evm/State.ts
rename to packages/evm/src/State.ts
diff --git a/packages/evm/src/cloneBlock.ts b/packages/evm/src/cloneBlock.ts
deleted file mode 100644
index 6419a20..0000000
--- a/packages/evm/src/cloneBlock.ts
+++ /dev/null
@@ -1,31 +0,0 @@
-import { Bytes20, Bytes32, Account, Block } from './model'
-
-export function cloneBlock (block: Block): Block {
-  return {
-    parent: block.parent,
-    accounts: cloneAccounts(block.accounts),
-    transactions: [...block.transactions],
-    parameters: { ...block.parameters },
-  }
-}
-
-function cloneAccounts (accounts: Map<Bytes20, Account>) {
-  const clone = new Map<Bytes20, Account>()
-  for (const [address, account] of accounts) {
-    clone.set(address, cloneAccount(account))
-  }
-  return clone
-}
-
-function cloneAccount (account: Account): Account {
-  return {
-    balance: account.balance,
-    code: account.code,
-    nonce: account.nonce,
-    storage: cloneStorage(account.storage),
-  }
-}
-
-function cloneStorage (storage: Map<Bytes32, Bytes32>) {
-  return new Map<Bytes32, Bytes32>(storage)
-}
diff --git a/packages/evm/src/createBlock.ts b/packages/evm/src/createBlock.ts
deleted file mode 100644
index 0b8d5a7..0000000
--- a/packages/evm/src/createBlock.ts
+++ /dev/null
@@ -1,16 +0,0 @@
-import { Block, PendingTransaction, BlockParameters } from './model'
-import { includeTransactions } from './includeTransactions'
-
-export function createBlock (
-  parent: Block,
-  transactions: PendingTransaction[],
-  parameters: BlockParameters,
-): Block {
-  const block = {
-    parent,
-    accounts: parent.accounts,
-    parameters: { ...parameters },
-    transactions: [],
-  }
-  return includeTransactions(block, transactions)
-}
diff --git a/packages/evm/src/createGenesisBlock.ts b/packages/evm/src/createGenesisBlock.ts
deleted file mode 100644
index d4cfd5e..0000000
--- a/packages/evm/src/createGenesisBlock.ts
+++ /dev/null
@@ -1,28 +0,0 @@
-import { Block, Bytes20, Bytes32, Account, BlockParameters } from './model'
-
-export interface GenesisBlockParams {
-  balances: Map<Bytes20, Bytes32>,
-  parameters: BlockParameters,
-}
-
-export function createGenesisBlock (params: GenesisBlockParams): Block {
-  return {
-    parent: undefined,
-    accounts: accountsFromBalances(params.balances),
-    transactions: [],
-    parameters: { ...params.parameters },
-  }
-}
-
-function accountsFromBalances (balances: Map<Bytes20, Bytes32>) {
-  const accounts = new Map<Bytes20, Account>()
-  for (const [address, balance] of balances) {
-    accounts.set(address, {
-      balance,
-      storage: new Map(),
-      nonce: 0,
-      code: '0x',
-    })
-  }
-  return accounts
-}
diff --git a/packages/evm/src/evm/errors.ts b/packages/evm/src/errors.ts
similarity index 100%
rename from packages/evm/src/evm/errors.ts
rename to packages/evm/src/errors.ts
diff --git a/packages/evm/src/evm/Message.ts b/packages/evm/src/evm/Message.ts
deleted file mode 100644
index 0db728a..0000000
--- a/packages/evm/src/evm/Message.ts
+++ /dev/null
@@ -1,18 +0,0 @@
-import { Address } from './Address'
-import { Bytes32 } from './Bytes32'
-import { Byte } from './Byte'
-import { State } from './State'
-
-export interface Message {
-  account: Address,
-  code: Byte[],
-  data: Byte[],
-  origin: Address,
-  sender: Address,
-  gasLimit: number,
-  gasPrice: Bytes32,
-  value: Bytes32,
-  enableStateModifications: boolean,
-  callDepth: number,
-  state: State,
-}
diff --git a/packages/evm/src/evm/executeCode.ts b/packages/evm/src/evm/executeCode.ts
deleted file mode 100644
index 4f775a3..0000000
--- a/packages/evm/src/evm/executeCode.ts
+++ /dev/null
@@ -1,53 +0,0 @@
-import { Byte } from './Byte'
-import { ExecutionContext } from './ExecutionContext'
-import { Memory } from './Memory'
-import { Message } from './Message'
-import { opSTOP } from './opcodes/control'
-import { Stack } from './Stack'
-import { State } from './State'
-import { VMError } from './errors'
-
-export interface ExecutionResult {
-  stack: Stack,
-  memory: Memory,
-  state: State,
-  gasUsed: number,
-  gasRefund: number,
-  programCounter: number,
-  reverted: boolean,
-  returnValue?: Byte[],
-  error?: VMError,
-}
-
-export function executeCode (message: Message): ExecutionResult {
-  const ctx = new ExecutionContext(message)
-  while (ctx.returnValue === undefined) {
-    const opcode = ctx.code[ctx.programCounter] || opSTOP
-    ctx.programCounter++
-    try {
-      opcode(ctx)
-    } catch (e) {
-      if (e instanceof VMError) {
-        ctx.useRemainingGas()
-        return toResult(ctx, e)
-      } else {
-        throw e // this should never happen
-      }
-    }
-  }
-  return toResult(ctx)
-}
-
-function toResult (ctx: ExecutionContext, error?: VMError): ExecutionResult {
-  return {
-    stack: ctx.stack,
-    memory: ctx.memory.memory,
-    state: (ctx.reverted || error) ? ctx.message.state : ctx.state,
-    gasUsed: ctx.gasUsed,
-    gasRefund: ctx.gasRefund,
-    reverted: ctx.reverted,
-    programCounter: ctx.programCounter,
-    returnValue: ctx.returnValue,
-    error,
-  }
-}
diff --git a/packages/evm/src/executeCode.ts b/packages/evm/src/executeCode.ts
new file mode 100644
index 0000000..5019df8
--- /dev/null
+++ b/packages/evm/src/executeCode.ts
@@ -0,0 +1,44 @@
+import { ExecutionContext } from './ExecutionContext'
+import { Message } from './Message'
+import { opSTOP } from './opcodes/control'
+import { VMError } from './errors'
+import { ExecutionResult } from './ExecutionResult'
+import { State } from './State'
+
+export function executeCode (message: Message, state: State): ExecutionResult {
+  const ctx = new ExecutionContext(message, state)
+
+  while (ctx.returnValue === undefined) {
+    const opcode = ctx.code[ctx.programCounter] || opSTOP
+    ctx.programCounter++
+    try {
+      opcode(ctx)
+    } catch (error) {
+      if (error instanceof VMError) {
+        return {
+          type: 'ExecutionError',
+          error,
+        }
+      } else {
+        // programmer error
+        throw error
+      }
+    }
+  }
+
+  if (ctx.reverted) {
+    return {
+      type: 'ExecutionRevert',
+      gasUsed: ctx.gasUsed,
+      returnValue: ctx.returnValue,
+    }
+  } else {
+    return {
+      type: 'ExecutionSuccess',
+      gasUsed: ctx.gasUsed,
+      gasRefund: ctx.gasRefund,
+      returnValue: ctx.returnValue,
+      state: ctx.state,
+    }
+  }
+}
diff --git a/packages/evm/src/executeTransaction.ts b/packages/evm/src/executeTransaction.ts
deleted file mode 100644
index 57bec59..0000000
--- a/packages/evm/src/executeTransaction.ts
+++ /dev/null
@@ -1,27 +0,0 @@
-import { Bytes20, Log, Block, PendingTransaction } from './model'
-import { ExecutionError } from './model/ExecutionError'
-
-export interface TransactionExecutionResult {
-  gasUsed: number,
-  contractAddress: Bytes20 | null,
-  logs: Log[],
-  error: ExecutionError | null,
-}
-
-/**
- * Alter block state and return transaction execution results
- * @param block a block to execute the transaction on
- * @param transaction a transaction to execute
- */
-export function executeTransaction (
-  block: Block,
-  transaction: PendingTransaction,
-): TransactionExecutionResult {
-  // TODO: real implementation
-  return {
-    gasUsed: 21_000,
-    contractAddress: null,
-    logs: [],
-    error: null,
-  }
-}
diff --git a/packages/evm/src/includeTransactions.ts b/packages/evm/src/includeTransactions.ts
deleted file mode 100644
index 2a41d01..0000000
--- a/packages/evm/src/includeTransactions.ts
+++ /dev/null
@@ -1,51 +0,0 @@
-import { Block, PendingTransaction } from './model'
-import { cloneBlock } from './cloneBlock'
-import { executeTransaction } from './executeTransaction'
-
-export function includeTransactions (
-  block: Block,
-  transactions: PendingTransaction[],
-): Block {
-  return transactions.reduce(includeTransaction, block)
-}
-
-function includeTransaction (
-  block: Block,
-  transaction: PendingTransaction,
-): Block {
-  const cloned = cloneBlock(block)
-
-  const result = executeTransaction(cloned, transaction)
-
-  if (!result.error) {
-    cloned.parameters.gasUsed += result.gasUsed
-    cloned.transactions.push({
-      from: transaction.from,
-      to: transaction.to,
-      hash: transaction.hash,
-      contractAddress: result.contractAddress,
-      logs: result.logs,
-      gasUsed: result.gasUsed,
-      cumulativeGasUsed: cloned.parameters.gasUsed,
-      error: null,
-    })
-
-    return cloned
-  } else {
-    const reverted = cloneBlock(block)
-
-    reverted.parameters.gasUsed += result.gasUsed
-    reverted.transactions.push({
-      from: transaction.from,
-      to: transaction.to,
-      hash: transaction.hash,
-      contractAddress: null,
-      logs: [],
-      gasUsed: result.gasUsed,
-      cumulativeGasUsed: reverted.parameters.gasUsed,
-      error: result.error,
-    })
-
-    return reverted
-  }
-}
diff --git a/packages/evm/src/model/Account.ts b/packages/evm/src/model/Account.ts
deleted file mode 100644
index 7d7ac5a..0000000
--- a/packages/evm/src/model/Account.ts
+++ /dev/null
@@ -1,8 +0,0 @@
-import { Bytes32, Bytes } from './utils'
-
-export interface Account {
-  balance: Bytes32,
-  nonce: number,
-  storage: Map<Bytes32, Bytes32>,
-  code: Bytes,
-}
diff --git a/packages/evm/src/model/Block.ts b/packages/evm/src/model/Block.ts
deleted file mode 100644
index a75a8f1..0000000
--- a/packages/evm/src/model/Block.ts
+++ /dev/null
@@ -1,20 +0,0 @@
-import { ExecutedTransaction } from './ExecutedTransaction'
-import { Account } from './Account'
-import { Bytes20, Bytes32, Bytes } from './utils'
-
-export interface Block {
-  parent?: Block,
-  accounts: Map<Bytes20, Account>,
-  transactions: ExecutedTransaction[],
-  parameters: BlockParameters,
-}
-
-export interface BlockParameters {
-  hash: Bytes32,
-  number: number,
-  timestamp: number,
-  gasLimit: number,
-  gasUsed: number,
-  extraData: Bytes,
-  miner: Bytes20,
-}
diff --git a/packages/evm/src/model/ExecutedTransaction.ts b/packages/evm/src/model/ExecutedTransaction.ts
deleted file mode 100644
index 59ac8e7..0000000
--- a/packages/evm/src/model/ExecutedTransaction.ts
+++ /dev/null
@@ -1,14 +0,0 @@
-import { Bytes32, Bytes20 } from './utils'
-import { Log } from './Log'
-import { ExecutionError } from './ExecutionError'
-
-export interface ExecutedTransaction {
-  hash: Bytes32,
-  from: Bytes20,
-  to: Bytes20,
-  gasUsed: number,
-  cumulativeGasUsed: number,
-  contractAddress: Bytes20 | null,
-  logs: Log[],
-  error: ExecutionError | null,
-}
diff --git a/packages/evm/src/model/ExecutionError.ts b/packages/evm/src/model/ExecutionError.ts
deleted file mode 100644
index d9fe0da..0000000
--- a/packages/evm/src/model/ExecutionError.ts
+++ /dev/null
@@ -1,3 +0,0 @@
-export interface ExecutionError {
-  message: string,
-}
diff --git a/packages/evm/src/model/Log.ts b/packages/evm/src/model/Log.ts
deleted file mode 100644
index 2c110c9..0000000
--- a/packages/evm/src/model/Log.ts
+++ /dev/null
@@ -1,7 +0,0 @@
-import { Bytes, Bytes32, Bytes20 } from './utils'
-
-export interface Log {
-  address: Bytes20,
-  data: Bytes,
-  topics: Bytes32[],
-}
diff --git a/packages/evm/src/model/PendingTransaction.ts b/packages/evm/src/model/PendingTransaction.ts
deleted file mode 100644
index 3d5c02c..0000000
--- a/packages/evm/src/model/PendingTransaction.ts
+++ /dev/null
@@ -1,8 +0,0 @@
-import { Bytes32, Bytes20 } from './utils'
-
-export interface PendingTransaction {
-  hash: Bytes32,
-  from: Bytes20,
-  to: Bytes20,
-  value: Bytes32,
-}
diff --git a/packages/evm/src/model/index.ts b/packages/evm/src/model/index.ts
deleted file mode 100644
index 85488f4..0000000
--- a/packages/evm/src/model/index.ts
+++ /dev/null
@@ -1,8 +0,0 @@
-export * from './Account'
-export * from './Block'
-export * from './ExecutedTransaction'
-export * from './ExecutionError'
-export * from './Log'
-export * from './PendingTransaction'
-export * from './PendingTransaction'
-export * from './utils'
diff --git a/packages/evm/src/model/utils.ts b/packages/evm/src/model/utils.ts
deleted file mode 100644
index 25b61d5..0000000
--- a/packages/evm/src/model/utils.ts
+++ /dev/null
@@ -1,4 +0,0 @@
-export type Bytes20 = string
-export type Bytes32 = string
-export type Bytes256 = string
-export type Bytes = string
diff --git a/packages/evm/src/evm/opcodes/Opcode.ts b/packages/evm/src/opcodes/Opcode.ts
similarity index 100%
rename from packages/evm/src/evm/opcodes/Opcode.ts
rename to packages/evm/src/opcodes/Opcode.ts
diff --git a/packages/evm/src/evm/opcodes/bytes32.ts b/packages/evm/src/opcodes/bytes32.ts
similarity index 100%
rename from packages/evm/src/evm/opcodes/bytes32.ts
rename to packages/evm/src/opcodes/bytes32.ts
diff --git a/packages/evm/src/evm/opcodes/control.ts b/packages/evm/src/opcodes/control.ts
similarity index 100%
rename from packages/evm/src/evm/opcodes/control.ts
rename to packages/evm/src/opcodes/control.ts
diff --git a/packages/evm/src/evm/opcodes/gasCosts.ts b/packages/evm/src/opcodes/gasCosts.ts
similarity index 91%
rename from packages/evm/src/evm/opcodes/gasCosts.ts
rename to packages/evm/src/opcodes/gasCosts.ts
index ba47026..6c7d06b 100644
--- a/packages/evm/src/evm/opcodes/gasCosts.ts
+++ b/packages/evm/src/opcodes/gasCosts.ts
@@ -10,6 +10,7 @@ export const GasCost = {
   SLOAD: 200,
   SSET: 20_000,
   SRESET: 5_000,
+  CODEDEPOSIT: 200,
 }
 
 export const GasRefund = {
diff --git a/packages/evm/src/evm/opcodes/helpers.ts b/packages/evm/src/opcodes/helpers.ts
similarity index 100%
rename from packages/evm/src/evm/opcodes/helpers.ts
rename to packages/evm/src/opcodes/helpers.ts
diff --git a/packages/evm/src/evm/opcodes/index.ts b/packages/evm/src/opcodes/index.ts
similarity index 100%
rename from packages/evm/src/evm/opcodes/index.ts
rename to packages/evm/src/opcodes/index.ts
diff --git a/packages/evm/src/evm/opcodes/invalid.ts b/packages/evm/src/opcodes/invalid.ts
similarity index 100%
rename from packages/evm/src/evm/opcodes/invalid.ts
rename to packages/evm/src/opcodes/invalid.ts
diff --git a/packages/evm/src/evm/opcodes/memory.ts b/packages/evm/src/opcodes/memory.ts
similarity index 100%
rename from packages/evm/src/evm/opcodes/memory.ts
rename to packages/evm/src/opcodes/memory.ts
diff --git a/packages/evm/src/evm/opcodes/stack.ts b/packages/evm/src/opcodes/stack.ts
similarity index 100%
rename from packages/evm/src/evm/opcodes/stack.ts
rename to packages/evm/src/opcodes/stack.ts
diff --git a/packages/evm/src/evm/opcodes/storage.ts b/packages/evm/src/opcodes/storage.ts
similarity index 100%
rename from packages/evm/src/evm/opcodes/storage.ts
rename to packages/evm/src/opcodes/storage.ts
diff --git a/packages/evm/src/evm/parseBytecode.ts b/packages/evm/src/parseBytecode.ts
similarity index 90%
rename from packages/evm/src/evm/parseBytecode.ts
rename to packages/evm/src/parseBytecode.ts
index d827deb..cc0277d 100644
--- a/packages/evm/src/evm/parseBytecode.ts
+++ b/packages/evm/src/parseBytecode.ts
@@ -2,11 +2,13 @@ import { InvalidBytecode } from './errors'
 import { Opcode, getOpcode, makeOpPUSH, opUnreachable } from './opcodes'
 import { Byte } from './Byte'
 
-export function parseBytecode (bytes: Byte[]) {
+export function parseBytecode (bytes: readonly Byte[]) {
   const result: Opcode[] = []
   for (let i = 0; i < bytes.length; i++) {
     const pushSize = getPushSize(bytes[i])
-    if (pushSize !== 0) {
+    if (pushSize === 0) {
+      result.push(getOpcode(bytes[i]))
+    } else {
       if (i + pushSize >= bytes.length) {
         throw new InvalidBytecode()
       }
@@ -16,8 +18,6 @@ export function parseBytecode (bytes: Byte[]) {
         result.push(opUnreachable)
       }
       i += pushSize
-    } else {
-      result.push(getOpcode(bytes[i]))
     }
   }
   return result
diff --git a/packages/evm/test/evm/Bytes32.test.ts b/packages/evm/test/Bytes32.test.ts
similarity index 98%
rename from packages/evm/test/evm/Bytes32.test.ts
rename to packages/evm/test/Bytes32.test.ts
index 6e93fb7..a0ae3d3 100644
--- a/packages/evm/test/evm/Bytes32.test.ts
+++ b/packages/evm/test/Bytes32.test.ts
@@ -1,8 +1,8 @@
 import { expect } from 'chai'
-import { Bytes32 } from '../../src/evm/Bytes32'
+import { Bytes32 } from '../src/Bytes32'
 import { TestCases } from './opcodes/bytes32/cases'
 import { TestCase } from './opcodes/bytes32/cases/helpers'
-import { Byte } from '../../src/evm/Byte'
+import { Byte } from '../src/Byte'
 
 describe('Bytes32', () => {
   runTestCases('add', TestCases.ADD)
diff --git a/packages/evm/test/evm/ExecutionContext.test.ts b/packages/evm/test/ExecutionContext.test.ts
similarity index 75%
rename from packages/evm/test/evm/ExecutionContext.test.ts
rename to packages/evm/test/ExecutionContext.test.ts
index c4d6cb2..70572bc 100644
--- a/packages/evm/test/evm/ExecutionContext.test.ts
+++ b/packages/evm/test/ExecutionContext.test.ts
@@ -1,14 +1,15 @@
 import { expect } from 'chai'
-import { ExecutionContext } from '../../src/evm/ExecutionContext'
-import { OutOfGas } from '../../src/evm/errors'
+import { ExecutionContext } from '../src/ExecutionContext'
+import { OutOfGas } from '../src/errors'
 import { DEFAULT_MESSAGE } from './helpers'
+import { State } from '../src/State'
 
 describe('ExecutionContext', () => {
   function makeContext (gasLimit: number) {
     return new ExecutionContext({
       ...DEFAULT_MESSAGE,
       gasLimit,
-    })
+    }, new State())
   }
 
   it('can track gas usage', () => {
@@ -25,12 +26,6 @@ describe('ExecutionContext', () => {
     expect(() => ctx.useGas(1)).to.throw(OutOfGas)
   })
 
-  it('can use all gas', () => {
-    const ctx = makeContext(300)
-    ctx.useRemainingGas()
-    expect(ctx.gasUsed).to.equal(300)
-  })
-
   it('can track refund', () => {
     const ctx = makeContext(Infinity)
     ctx.useGas(100)
diff --git a/packages/evm/test/Memory.test.ts b/packages/evm/test/Memory.test.ts
new file mode 100644
index 0000000..60966ba
--- /dev/null
+++ b/packages/evm/test/Memory.test.ts
@@ -0,0 +1,91 @@
+import { expect } from 'chai'
+import { Memory } from '../src/Memory'
+import { memoryGas } from './helpers'
+import { Byte } from '../src/Byte'
+
+describe('Memory', () => {
+  let gasUsed = 0
+  const useGas = (gas: number) => {
+    gasUsed += gas
+  }
+
+  beforeEach(() => {
+    gasUsed = 0
+  })
+
+  it('starts with zero size', () => {
+    const memory = new Memory(useGas)
+    expect(memory.getSize()).to.equal(0)
+  })
+
+  it('expands size and pads it to 32 bytes', () => {
+    const memory = new Memory(useGas)
+    memory.setBytes(0, [0xAB, 0xCD] as Byte[])
+    expect(memory.getSize()).to.equal(32)
+    memory.setBytes(31, [0xAB, 0xCD] as Byte[])
+    expect(memory.getSize()).to.equal(64)
+  })
+
+  it('expands filling space with zeroes', () => {
+    const memory = new Memory(useGas)
+    memory.setBytes(0, [0xAB, 0xCD] as Byte[])
+    memory.setBytes(3, [0xEF] as Byte[])
+    expect(memory.getBytes(0, 5)).to.deep.equal([0xAB, 0xCD, 0x00, 0xEF, 0x00])
+  })
+
+  it('getBytes results in memory expansion', () => {
+    const memory = new Memory(useGas)
+    const bytes = memory.getBytes(10, 1)
+    expect(bytes).to.deep.equal([0x00])
+    expect(memory.getSize()).to.equal(32)
+  })
+
+  it('zero length getBytes does not expand the memory', () => {
+    const memory = new Memory(useGas)
+    const bytes = memory.getBytes(10_000, 0)
+    expect(bytes).to.deep.equal([])
+    expect(memory.getSize()).to.equal(0)
+  })
+
+  it('zero length setBytes does not expand the memory', () => {
+    const memory = new Memory(useGas)
+    memory.setBytes(10_000, [])
+    expect(memory.getSize()).to.equal(0)
+  })
+
+  describe('gas usage', () => {
+    it('can track a single memory usage', () => {
+      const memory = new Memory(useGas)
+      memory.getBytes(300, 1)
+      expect(gasUsed).to.equal(memoryGas(301))
+    })
+
+    it('does not use any gas on zero length access', () => {
+      const memory = new Memory(useGas)
+      memory.getBytes(31415, 0)
+      expect(gasUsed).to.equal(0)
+    })
+
+    it('can track multiple memory uses', () => {
+      const memory = new Memory(useGas)
+      memory.getBytes(0, 100)
+      memory.getBytes(9_000, 2_000)
+      memory.getBytes(15_000_000, 3)
+      memory.getBytes(11, 12)
+      expect(gasUsed).to.equal(memoryGas(15_000_003))
+    })
+
+    it('tracks memory use for setBytes', () => {
+      const memory = new Memory(useGas)
+      memory.setBytes(300, [0xBA] as Byte[])
+      expect(gasUsed).to.equal(memoryGas(301))
+    })
+
+    it('forwards getSize', () => {
+      const memory = new Memory(useGas)
+      memory.setBytes(300, [0xBA] as Byte[])
+      const size = memory.getSize()
+      expect(size).to.equal(Math.ceil(301 / 32) * 32)
+    })
+  })
+})
diff --git a/packages/evm/test/evm/Stack.test.ts b/packages/evm/test/Stack.test.ts
similarity index 93%
rename from packages/evm/test/evm/Stack.test.ts
rename to packages/evm/test/Stack.test.ts
index 2d5ae43..1ecb8cf 100644
--- a/packages/evm/test/evm/Stack.test.ts
+++ b/packages/evm/test/Stack.test.ts
@@ -1,7 +1,7 @@
 import { expect } from 'chai'
-import { Bytes32 } from '../../src/evm/Bytes32'
-import { Stack } from '../../src/evm/Stack'
-import { StackOverflow, StackUnderflow } from '../../src/evm/errors'
+import { Bytes32 } from '../src/Bytes32'
+import { Stack } from '../src/Stack'
+import { StackOverflow, StackUnderflow } from '../src/errors'
 
 const A = Bytes32.ONE
 const B = A.add(A)
diff --git a/packages/evm/test/evm/State.test.ts b/packages/evm/test/State.test.ts
similarity index 95%
rename from packages/evm/test/evm/State.test.ts
rename to packages/evm/test/State.test.ts
index 1e94ee3..0f2f1fa 100644
--- a/packages/evm/test/evm/State.test.ts
+++ b/packages/evm/test/State.test.ts
@@ -1,7 +1,7 @@
 import { expect } from 'chai'
-import { State } from '../../src/evm/State'
-import { Bytes32 } from '../../src/evm/Bytes32'
-import { Byte } from '../../src/evm/Byte'
+import { State } from '../src/State'
+import { Bytes32 } from '../src/Bytes32'
+import { Byte } from '../src/Byte'
 import { ADDRESS_ZERO } from './helpers'
 
 describe('State', () => {
diff --git a/packages/evm/test/cloneBlock.test.ts b/packages/evm/test/cloneBlock.test.ts
deleted file mode 100644
index 61bce3e..0000000
--- a/packages/evm/test/cloneBlock.test.ts
+++ /dev/null
@@ -1,36 +0,0 @@
-import { expect } from 'chai'
-import { cloneBlock } from '../src/cloneBlock'
-import { Block, Account } from '../src/model'
-
-describe('cloneBlock', () => {
-  it('correctly clones a block', () => {
-    const account: Account = {
-      balance: '10',
-      code: '0x123',
-      nonce: 42,
-      storage: new Map([
-        ['1', '2'],
-        ['3', '4'],
-      ]),
-    }
-    const block: Block = {
-      accounts: new Map([
-        ['123', account],
-      ]),
-      parameters: {
-        gasLimit: 1000,
-      } as any,
-      transactions: [],
-    }
-    block.parent = block
-
-    const clone = cloneBlock(block)
-
-    expect(clone).to.deep.equal(block)
-    expect(clone.parent).to.equal(block)
-    expect(clone.accounts).not.to.equal(block.accounts)
-    expect(clone.accounts.get('123')).not.to.equal(block.accounts.get('123'))
-    expect(clone.parameters).not.to.equal(block.parameters)
-    expect(clone.transactions).not.to.equal(block.transactions)
-  })
-})
diff --git a/packages/evm/test/createGenesisBlock.test.ts b/packages/evm/test/createGenesisBlock.test.ts
deleted file mode 100644
index cfcc61a..0000000
--- a/packages/evm/test/createGenesisBlock.test.ts
+++ /dev/null
@@ -1,61 +0,0 @@
-import { expect } from 'chai'
-import { createGenesisBlock } from '../src/createGenesisBlock'
-import { BlockParameters } from '../src/model'
-
-describe('createGenesisBlock', () => {
-  const parameters: BlockParameters = {
-    extraData: '0x',
-    gasLimit: 1234,
-    gasUsed: 123,
-    hash: '0x12ab',
-    miner: '0x34bc',
-    number: 1,
-    timestamp: 100000,
-  }
-
-  it('creates an empty block', () => {
-    const block = createGenesisBlock({
-      balances: new Map(),
-      parameters,
-    })
-
-    expect(block).to.deep.equal({
-      parent: undefined,
-      accounts: new Map(),
-      transactions: [],
-      parameters,
-    })
-    expect(block.parameters).not.to.equal(parameters)
-  })
-
-  it('creates a block with some accounts', () => {
-    const block = createGenesisBlock({
-      balances: new Map([
-        ['0x1234', '0x4000'],
-        ['0x56EF', '0x2137'],
-      ]),
-      parameters,
-    })
-
-    expect(block).to.deep.equal({
-      parent: undefined,
-      accounts: new Map([
-        ['0x1234', {
-          balance: '0x4000',
-          storage: new Map(),
-          nonce: 0,
-          code: '0x',
-        }],
-        ['0x56EF', {
-          balance: '0x2137',
-          storage: new Map(),
-          nonce: 0,
-          code: '0x',
-        }],
-      ]),
-      transactions: [],
-      parameters,
-    })
-    expect(block.parameters).not.to.equal(parameters)
-  })
-})
diff --git a/packages/evm/test/evm/Memory.test.ts b/packages/evm/test/evm/Memory.test.ts
deleted file mode 100644
index 88fc73a..0000000
--- a/packages/evm/test/evm/Memory.test.ts
+++ /dev/null
@@ -1,91 +0,0 @@
-import { expect } from 'chai'
-import { Memory, GasAwareMemory } from '../../src/evm/Memory'
-import { memoryGas } from './helpers'
-import { Byte } from '../../src/evm/Byte'
-
-describe('Memory', () => {
-  it('starts with zero size', () => {
-    const memory = new Memory()
-    expect(memory.getSize()).to.equal(0)
-  })
-
-  it('expands size and pads it to 32 bytes', () => {
-    const memory = new Memory()
-    memory.setBytes(0, [0xAB, 0xCD] as Byte[])
-    expect(memory.getSize()).to.equal(32)
-    memory.setBytes(31, [0xAB, 0xCD] as Byte[])
-    expect(memory.getSize()).to.equal(64)
-  })
-
-  it('expands filling space with zeroes', () => {
-    const memory = new Memory()
-    memory.setBytes(0, [0xAB, 0xCD] as Byte[])
-    memory.setBytes(3, [0xEF] as Byte[])
-    expect(memory.getBytes(0, 5)).to.deep.equal([0xAB, 0xCD, 0x00, 0xEF, 0x00])
-  })
-
-  it('getBytes results in memory expansion', () => {
-    const memory = new Memory()
-    const bytes = memory.getBytes(10, 1)
-    expect(bytes).to.deep.equal([0x00])
-    expect(memory.getSize()).to.equal(32)
-  })
-
-  it('zero length getBytes does not expand the memory', () => {
-    const memory = new Memory()
-    const bytes = memory.getBytes(10_000, 0)
-    expect(bytes).to.deep.equal([])
-    expect(memory.getSize()).to.equal(0)
-  })
-
-  it('zero length setBytes does not expand the memory', () => {
-    const memory = new Memory()
-    memory.setBytes(10_000, [])
-    expect(memory.getSize()).to.equal(0)
-  })
-})
-
-describe('GasAwareMemory', () => {
-  let gasUsed = 0
-  const useGas = (gas: number) => {
-    gasUsed += gas
-  }
-
-  beforeEach(() => {
-    gasUsed = 0
-  })
-
-  it('can track a single memory usage', () => {
-    const memory = new GasAwareMemory(new Memory(), useGas)
-    memory.getBytes(300, 1)
-    expect(gasUsed).to.equal(memoryGas(301))
-  })
-
-  it('does not use any gas on zero length access', () => {
-    const memory = new GasAwareMemory(new Memory(), useGas)
-    memory.getBytes(31415, 0)
-    expect(gasUsed).to.equal(0)
-  })
-
-  it('can track multiple memory uses', () => {
-    const memory = new GasAwareMemory(new Memory(), useGas)
-    memory.getBytes(0, 100)
-    memory.getBytes(9_000, 2_000)
-    memory.getBytes(15_000_000, 3)
-    memory.getBytes(11, 12)
-    expect(gasUsed).to.equal(memoryGas(15_000_003))
-  })
-
-  it('tracks memory use for setBytes', () => {
-    const memory = new GasAwareMemory(new Memory(), useGas)
-    memory.setBytes(300, [0xBA] as Byte[])
-    expect(gasUsed).to.equal(memoryGas(301))
-  })
-
-  it('forwards getSize', () => {
-    const memory = new GasAwareMemory(new Memory(), useGas)
-    memory.setBytes(300, [0xBA] as Byte[])
-    const size = memory.getSize()
-    expect(size).to.equal(Math.ceil(301 / 32) * 32)
-  })
-})
diff --git a/packages/evm/test/evm/exception.test.ts b/packages/evm/test/evm/exception.test.ts
deleted file mode 100644
index 744e82c..0000000
--- a/packages/evm/test/evm/exception.test.ts
+++ /dev/null
@@ -1,37 +0,0 @@
-import { expect } from 'chai'
-import { executeAssembly, ADDRESS_ZERO } from './helpers'
-import { InvalidOpcode } from '../../src/evm/errors'
-import { Bytes32 } from '../../src/evm/Bytes32'
-import { State } from '../../src/evm/State'
-
-describe('When an exception occurs', () => {
-  it('all gas is used', () => {
-    const result = executeAssembly('INVALID', { gasLimit: 1_000_000 })
-
-    expect(result.error).to.be.instanceOf(InvalidOpcode)
-    expect(result.gasUsed).to.equal(1_000_000)
-  })
-
-  it('state changes are reverted', () => {
-    const account = ADDRESS_ZERO
-    const state = new State()
-    state.setStorage(account, Bytes32.ZERO, Bytes32.ONE)
-
-    const assembly = `
-      PUSH1 02
-      PUSH1 00
-      SSTORE
-      PUSH1 03
-      PUSH1 01
-      SSTORE
-      INVALID
-    `
-    const result = executeAssembly(assembly, { account, state })
-
-    expect(result.error).to.be.instanceOf(InvalidOpcode)
-    const storageAt0 = result.state.getStorage(account, Bytes32.ZERO)
-    const storageAt1 = result.state.getStorage(account, Bytes32.ONE)
-    expect(storageAt0.equals(Bytes32.ONE)).to.equal(true)
-    expect(storageAt1.equals(Bytes32.ZERO)).to.equal(true)
-  })
-})
diff --git a/packages/evm/test/evm/gasLimit.test.ts b/packages/evm/test/gasLimit.test.ts
similarity index 84%
rename from packages/evm/test/evm/gasLimit.test.ts
rename to packages/evm/test/gasLimit.test.ts
index af51059..4946860 100644
--- a/packages/evm/test/evm/gasLimit.test.ts
+++ b/packages/evm/test/gasLimit.test.ts
@@ -1,5 +1,5 @@
 import { expectError } from './helpers'
-import { OutOfGas } from '../../src/evm/errors'
+import { OutOfGas } from '../src/errors'
 
 describe('gasLimit', () => {
   it('fails with OutOfGas when reached', () => {
diff --git a/packages/evm/test/evm/helpers/Int256.ts b/packages/evm/test/helpers/Int256.ts
similarity index 93%
rename from packages/evm/test/evm/helpers/Int256.ts
rename to packages/evm/test/helpers/Int256.ts
index 95ec028..cced4b0 100644
--- a/packages/evm/test/evm/helpers/Int256.ts
+++ b/packages/evm/test/helpers/Int256.ts
@@ -1,4 +1,4 @@
-import { Bytes32 } from '../../../src/evm/Bytes32'
+import { Bytes32 } from '../../src/Bytes32'
 
 const HEX_REGEX = /^0x[\da-f]*$/
 
diff --git a/packages/evm/test/evm/helpers/executeAssembly.ts b/packages/evm/test/helpers/executeAssembly.ts
similarity index 86%
rename from packages/evm/test/evm/helpers/executeAssembly.ts
rename to packages/evm/test/helpers/executeAssembly.ts
index 16c3af9..2b3108a 100644
--- a/packages/evm/test/evm/helpers/executeAssembly.ts
+++ b/packages/evm/test/helpers/executeAssembly.ts
@@ -1,9 +1,9 @@
-import { executeCode } from '../../../src/evm/executeCode'
-import { State } from '../../../src/evm/State'
-import { Address } from '../../../src/evm/Address'
-import { Byte } from '../../../src/evm/Byte'
-import { Message } from '../../../src/evm/Message'
-import { Bytes32 } from '../../../src/evm/Bytes32'
+import { executeCode } from '../../src/executeCode'
+import { State } from '../../src/State'
+import { Address } from '../../src/Address'
+import { Byte } from '../../src/Byte'
+import { Message } from '../../src/Message'
+import { Bytes32 } from '../../src/Bytes32'
 
 export const ADDRESS_ZERO = '0'.repeat(40) as Address
 
@@ -13,7 +13,6 @@ export const DEFAULT_MESSAGE: Message = {
   origin: ADDRESS_ZERO,
   gasLimit: 1_000_000_000,
   gasPrice: Bytes32.ZERO,
-  state: new State(),
   callDepth: 0,
   data: [],
   enableStateModifications: true,
@@ -21,9 +20,13 @@ export const DEFAULT_MESSAGE: Message = {
   code: [],
 }
 
-export function executeAssembly (assembly: string, params?: Partial<Message>) {
+export function executeAssembly (
+  assembly: string,
+  params?: Partial<Message>,
+  state = new State(),
+) {
   const code = assemblyToBytecode(assembly)
-  return executeCode({ ...DEFAULT_MESSAGE, ...params, code })
+  return executeCode({ ...DEFAULT_MESSAGE, ...params, code }, state)
 }
 
 function assemblyToBytecode (code: string): Byte[] {
diff --git a/packages/evm/test/evm/helpers/expectations.ts b/packages/evm/test/helpers/expectations.ts
similarity index 52%
rename from packages/evm/test/evm/helpers/expectations.ts
rename to packages/evm/test/helpers/expectations.ts
index 638afb8..4492592 100644
--- a/packages/evm/test/evm/helpers/expectations.ts
+++ b/packages/evm/test/helpers/expectations.ts
@@ -1,9 +1,10 @@
 import { expect } from 'chai'
-import { StackUnderflow } from '../../../src/evm/errors'
+import { StackUnderflow } from '../../src/errors'
 import { executeAssembly, ADDRESS_ZERO } from './executeAssembly'
 import { Int256 } from './Int256'
-import { Bytes32 } from '../../../src/evm/Bytes32'
-import { Byte } from '../../../src/evm/Byte'
+import { Bytes32 } from '../../src/Bytes32'
+import { Byte } from '../../src/Byte'
+import { ExecutionSuccess } from '../../src/ExecutionResult'
 
 export function expectUnderflow (opcode: string, minimumDepth: number) {
   for (let i = 0; i < minimumDepth; i++) {
@@ -17,46 +18,53 @@ export function makeStack (depth: number) {
     .map((value, index) => Int256.of(depth - index))
 }
 
-export function expectStack (assembly: string, stack: string[]) {
-  const result = executeAssembly(assembly)
-  const items = result.stack['items'].map(x => x.toHex())
-  expect(items).to.deep.equal(stack)
+export function expectStackTop (assembly: string, value: string) {
+  const account = ADDRESS_ZERO
+  const result = executeAssembly(assembly + ' PUSH1 00 SSTORE', { account })
+  if (result.type !== 'ExecutionSuccess') {
+    throw new Error(result.type)
+  }
+  const item = result.state.getStorage(account, Bytes32.ZERO)
+  expect(item.toHex()).to.equal(value)
 }
 
 export function expectGas (assembly: string, gasUsed: number) {
   const result = executeAssembly(assembly)
-  expect(result.gasUsed).to.equal(gasUsed)
+  expect(result).to.include({ gasUsed })
 }
 
-export function expectRefund (assembly: string, refund: number) {
+export function expectRefund (assembly: string, gasRefund: number) {
   const result = executeAssembly(assembly)
-  expect(result.gasRefund).to.equal(refund)
+  expect(result).to.include({ gasRefund })
 }
 
 export function expectError (assembly: string, error: unknown) {
   const result = executeAssembly(assembly)
-  expect(result.error).to.be.instanceOf(error)
+  expect(result.type).to.equal('ExecutionError')
+  expect((result as any).error).to.be.instanceOf(error)
 }
 
 export function expectReturn (assembly: string, value: Byte[]) {
   const result = executeAssembly(assembly)
-  expect(result.reverted).to.equal(false)
-  expect(result.returnValue).to.deep.equal(value)
+  expect(result.type).to.equal('ExecutionSuccess')
+  expect((result as any).returnValue).to.deep.equal(value)
 }
 
 export function expectRevert (assembly: string, value: Byte[]) {
   const result = executeAssembly(assembly)
-  expect(result.reverted).to.equal(true)
-  expect(result.returnValue).to.deep.equal(value)
+  expect(result.type).to.equal('ExecutionRevert')
+  expect((result as any).returnValue).to.deep.equal(value)
 }
 
 export function expectStorage (assembly: string, values: Record<string, string>) {
   const account = ADDRESS_ZERO
   const result = executeAssembly(assembly, { account })
   const resultingStorage: Record<string, string> = {}
+  expect(result.type).to.equal('ExecutionSuccess')
+  const state = (result as ExecutionSuccess).state
   for (const key in values) {
     const location = Bytes32.fromHex(key)
-    resultingStorage[key] = result.state.getStorage(account, location).toHex()
+    resultingStorage[key] = state.getStorage(account, location).toHex()
   }
   expect(resultingStorage).to.deep.equal(values)
 }
diff --git a/packages/evm/test/evm/helpers/index.ts b/packages/evm/test/helpers/index.ts
similarity index 100%
rename from packages/evm/test/evm/helpers/index.ts
rename to packages/evm/test/helpers/index.ts
diff --git a/packages/evm/test/evm/helpers/memory.ts b/packages/evm/test/helpers/memory.ts
similarity index 100%
rename from packages/evm/test/evm/helpers/memory.ts
rename to packages/evm/test/helpers/memory.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/deth/add.ts b/packages/evm/test/opcodes/bytes32/cases/deth/add.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/deth/add.ts
rename to packages/evm/test/opcodes/bytes32/cases/deth/add.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/README.md b/packages/evm/test/opcodes/bytes32/cases/geth/README.md
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/README.md
rename to packages/evm/test/opcodes/bytes32/cases/geth/README.md
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/add.json b/packages/evm/test/opcodes/bytes32/cases/geth/add.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/add.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/add.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/and.json b/packages/evm/test/opcodes/bytes32/cases/geth/and.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/and.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/and.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/byte.json b/packages/evm/test/opcodes/bytes32/cases/geth/byte.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/byte.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/byte.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/div.json b/packages/evm/test/opcodes/bytes32/cases/geth/div.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/div.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/div.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/eq.json b/packages/evm/test/opcodes/bytes32/cases/geth/eq.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/eq.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/eq.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/exp.json b/packages/evm/test/opcodes/bytes32/cases/geth/exp.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/exp.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/exp.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/gt.json b/packages/evm/test/opcodes/bytes32/cases/geth/gt.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/gt.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/gt.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/lt.json b/packages/evm/test/opcodes/bytes32/cases/geth/lt.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/lt.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/lt.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/mod.json b/packages/evm/test/opcodes/bytes32/cases/geth/mod.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/mod.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/mod.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/mul.json b/packages/evm/test/opcodes/bytes32/cases/geth/mul.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/mul.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/mul.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/or.json b/packages/evm/test/opcodes/bytes32/cases/geth/or.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/or.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/or.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/sar.json b/packages/evm/test/opcodes/bytes32/cases/geth/sar.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/sar.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/sar.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/sdiv.json b/packages/evm/test/opcodes/bytes32/cases/geth/sdiv.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/sdiv.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/sdiv.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/sgt.json b/packages/evm/test/opcodes/bytes32/cases/geth/sgt.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/sgt.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/sgt.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/shl.json b/packages/evm/test/opcodes/bytes32/cases/geth/shl.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/shl.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/shl.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/shr.json b/packages/evm/test/opcodes/bytes32/cases/geth/shr.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/shr.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/shr.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/signextend.json b/packages/evm/test/opcodes/bytes32/cases/geth/signextend.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/signextend.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/signextend.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/slt.json b/packages/evm/test/opcodes/bytes32/cases/geth/slt.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/slt.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/slt.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/smod.json b/packages/evm/test/opcodes/bytes32/cases/geth/smod.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/smod.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/smod.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/sub.json b/packages/evm/test/opcodes/bytes32/cases/geth/sub.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/sub.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/sub.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/geth/xor.json b/packages/evm/test/opcodes/bytes32/cases/geth/xor.json
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/geth/xor.json
rename to packages/evm/test/opcodes/bytes32/cases/geth/xor.json
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/helpers.ts b/packages/evm/test/opcodes/bytes32/cases/helpers.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/helpers.ts
rename to packages/evm/test/opcodes/bytes32/cases/helpers.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/index.ts b/packages/evm/test/opcodes/bytes32/cases/index.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/index.ts
rename to packages/evm/test/opcodes/bytes32/cases/index.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/README.md b/packages/evm/test/opcodes/bytes32/cases/parity/README.md
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/README.md
rename to packages/evm/test/opcodes/bytes32/cases/parity/README.md
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/add.ts b/packages/evm/test/opcodes/bytes32/cases/parity/add.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/add.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/add.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/addmod.ts b/packages/evm/test/opcodes/bytes32/cases/parity/addmod.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/addmod.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/addmod.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/and.ts b/packages/evm/test/opcodes/bytes32/cases/parity/and.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/and.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/and.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/byte.ts b/packages/evm/test/opcodes/bytes32/cases/parity/byte.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/byte.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/byte.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/div.ts b/packages/evm/test/opcodes/bytes32/cases/parity/div.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/div.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/div.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/eq.ts b/packages/evm/test/opcodes/bytes32/cases/parity/eq.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/eq.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/eq.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/exp.ts b/packages/evm/test/opcodes/bytes32/cases/parity/exp.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/exp.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/exp.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/gt.ts b/packages/evm/test/opcodes/bytes32/cases/parity/gt.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/gt.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/gt.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/iszero.ts b/packages/evm/test/opcodes/bytes32/cases/parity/iszero.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/iszero.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/iszero.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/lt.ts b/packages/evm/test/opcodes/bytes32/cases/parity/lt.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/lt.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/lt.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/mod.ts b/packages/evm/test/opcodes/bytes32/cases/parity/mod.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/mod.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/mod.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/mul.ts b/packages/evm/test/opcodes/bytes32/cases/parity/mul.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/mul.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/mul.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/mulmod.ts b/packages/evm/test/opcodes/bytes32/cases/parity/mulmod.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/mulmod.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/mulmod.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/not.ts b/packages/evm/test/opcodes/bytes32/cases/parity/not.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/not.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/not.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/or.ts b/packages/evm/test/opcodes/bytes32/cases/parity/or.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/or.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/or.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/sar.ts b/packages/evm/test/opcodes/bytes32/cases/parity/sar.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/sar.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/sar.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/sdiv.ts b/packages/evm/test/opcodes/bytes32/cases/parity/sdiv.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/sdiv.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/sdiv.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/sgt.ts b/packages/evm/test/opcodes/bytes32/cases/parity/sgt.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/sgt.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/sgt.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/shl.ts b/packages/evm/test/opcodes/bytes32/cases/parity/shl.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/shl.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/shl.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/shr.ts b/packages/evm/test/opcodes/bytes32/cases/parity/shr.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/shr.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/shr.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/signextend.ts b/packages/evm/test/opcodes/bytes32/cases/parity/signextend.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/signextend.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/signextend.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/slt.ts b/packages/evm/test/opcodes/bytes32/cases/parity/slt.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/slt.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/slt.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/smod.ts b/packages/evm/test/opcodes/bytes32/cases/parity/smod.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/smod.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/smod.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/sub.ts b/packages/evm/test/opcodes/bytes32/cases/parity/sub.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/sub.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/sub.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/cases/parity/xor.ts b/packages/evm/test/opcodes/bytes32/cases/parity/xor.ts
similarity index 100%
rename from packages/evm/test/evm/opcodes/bytes32/cases/parity/xor.ts
rename to packages/evm/test/opcodes/bytes32/cases/parity/xor.ts
diff --git a/packages/evm/test/evm/opcodes/bytes32/machineWord.test.ts b/packages/evm/test/opcodes/bytes32/machineWord.test.ts
similarity index 93%
rename from packages/evm/test/evm/opcodes/bytes32/machineWord.test.ts
rename to packages/evm/test/opcodes/bytes32/machineWord.test.ts
index 836ebee..bdb0e9f 100644
--- a/packages/evm/test/evm/opcodes/bytes32/machineWord.test.ts
+++ b/packages/evm/test/opcodes/bytes32/machineWord.test.ts
@@ -1,7 +1,7 @@
 import { TestCases } from './cases'
 import { TestCase } from './cases/helpers'
-import { expectStack, expectGas } from '../../helpers'
-import { GasCost } from '../../../../src/evm/opcodes'
+import { expectGas, expectStackTop } from '../../helpers'
+import { GasCost } from '../../../src/opcodes'
 
 describe('bytes32 opcodes', () => {
   runTestCases('ADD', TestCases.ADD)
@@ -65,9 +65,9 @@ function runTestCases (opcode: string, testCases: TestCase[]) {
       it(testCase.title, () => {
         const assembly = testCase.stack
           .map(x => `PUSH32 ${x}`)
-          .concat(opcode)
+          .concat([opcode])
           .join(' ')
-        expectStack(assembly, [testCase.expected])
+        expectStackTop(assembly, testCase.expected)
       })
     }
   })
diff --git a/packages/evm/test/evm/opcodes/dup.test.ts b/packages/evm/test/opcodes/dup.test.ts
similarity index 66%
rename from packages/evm/test/evm/opcodes/dup.test.ts
rename to packages/evm/test/opcodes/dup.test.ts
index ecfc887..a32e18c 100644
--- a/packages/evm/test/evm/opcodes/dup.test.ts
+++ b/packages/evm/test/opcodes/dup.test.ts
@@ -1,5 +1,5 @@
-import { GasCost } from '../../../src/evm/opcodes/gasCosts'
-import { makeStack, expectUnderflow, expectStack, expectGas } from '../helpers'
+import { GasCost } from '../../src/opcodes/gasCosts'
+import { makeStack, expectUnderflow, expectGas, expectStackTop } from '../helpers'
 
 describe('DUP* opcodes', () => {
   const stack = makeStack(16)
@@ -10,10 +10,7 @@ describe('DUP* opcodes', () => {
   for (let n = 1; n <= 16; n++) {
     describe(`DUP${n}`, () => {
       it('duplicates the value on the stack', () => {
-        expectStack(`${assembly} DUP${n}`, [
-          ...stack,
-          stack[stack.length - n],
-        ])
+        expectStackTop(`${assembly} DUP${n}`, stack[stack.length - n])
       })
 
       it('can cause stack underflow', () => {
diff --git a/packages/evm/test/evm/opcodes/invalid.test.ts b/packages/evm/test/opcodes/invalid.test.ts
similarity index 92%
rename from packages/evm/test/evm/opcodes/invalid.test.ts
rename to packages/evm/test/opcodes/invalid.test.ts
index 2c46793..4aa4685 100644
--- a/packages/evm/test/evm/opcodes/invalid.test.ts
+++ b/packages/evm/test/opcodes/invalid.test.ts
@@ -1,4 +1,4 @@
-import { InvalidOpcode } from '../../../src/evm/errors'
+import { InvalidOpcode } from '../../src/errors'
 import { expectError } from '../helpers'
 
 describe('invalid opcodes', () => {
diff --git a/packages/evm/test/evm/opcodes/jump.test.ts b/packages/evm/test/opcodes/jump.test.ts
similarity index 82%
rename from packages/evm/test/evm/opcodes/jump.test.ts
rename to packages/evm/test/opcodes/jump.test.ts
index 28aedfe..46b6cc9 100644
--- a/packages/evm/test/evm/opcodes/jump.test.ts
+++ b/packages/evm/test/opcodes/jump.test.ts
@@ -1,6 +1,13 @@
-import { GasCost } from '../../../src/evm/opcodes/gasCosts'
-import { InvalidJumpDestination } from '../../../src/evm/errors'
-import { Int256, expectUnderflow, expectGas, expectStack, expectError } from '../helpers'
+import { GasCost } from '../../src/opcodes/gasCosts'
+import { InvalidJumpDestination } from '../../src/errors'
+import {
+  Int256,
+  expectUnderflow,
+  expectGas,
+  expectStackTop,
+  expectError,
+  expectStorage,
+} from '../helpers'
 
 describe('JUMP* opcodes', () => {
   describe('JUMPDEST', () => {
@@ -18,7 +25,7 @@ describe('JUMP* opcodes', () => {
 
     it('jumps to a specified location in code', () => {
       const assembly = 'PUSH1 04 JUMP STOP JUMPDEST PUSH1 01'
-      expectStack(assembly, [Int256.of(1)])
+      expectStackTop(assembly, Int256.of(1))
     })
 
     it('fails to jump to non JUMPDEST location', () => {
@@ -50,7 +57,7 @@ describe('JUMP* opcodes', () => {
         JUMPDEST
         PUSH1 FF
       `
-      expectStack(assembly, [Int256.of(0xff)])
+      expectStackTop(assembly, Int256.of(0xff))
     })
 
     it('does not jump if condition is zero', () => {
@@ -58,12 +65,13 @@ describe('JUMP* opcodes', () => {
         PUSH1 00
         PUSH1 08
         JUMPI
-        PUSH1 EE
         STOP
         JUMPDEST
         PUSH1 FF
+        PUSH1 00
+        SSTORE
       `
-      expectStack(assembly, [Int256.of(0xee)])
+      expectStorage(assembly, { '00': Int256.of(0) })
     })
 
     it('fails to jump to non JUMPDEST location', () => {
diff --git a/packages/evm/test/evm/opcodes/memory.test.ts b/packages/evm/test/opcodes/memory.test.ts
similarity index 86%
rename from packages/evm/test/evm/opcodes/memory.test.ts
rename to packages/evm/test/opcodes/memory.test.ts
index fbc67d6..84e8cf4 100644
--- a/packages/evm/test/evm/opcodes/memory.test.ts
+++ b/packages/evm/test/opcodes/memory.test.ts
@@ -1,5 +1,11 @@
-import { GasCost } from '../../../src/evm/opcodes'
-import { expectGas, memoryGas, expectStack, Int256, expectUnderflow } from '../helpers'
+import { GasCost } from '../../src/opcodes'
+import {
+  expectGas,
+  memoryGas,
+  expectStackTop,
+  Int256,
+  expectUnderflow,
+} from '../helpers'
 
 describe('Memory opcodes', () => {
   describe('MSIZE', () => {
@@ -8,13 +14,13 @@ describe('Memory opcodes', () => {
     })
 
     it('returns 0 initially', () => {
-      expectStack('MSIZE', [Int256.of(0)])
+      expectStackTop('MSIZE', Int256.of(0))
     })
 
     it('returns the size of memory used', () => {
       const assembly = 'PUSH1 00 PUSH3 100001 MSTORE MSIZE'
       const expected = Math.ceil((0x100001 + 32) / 32) * 32
-      expectStack(assembly, [Int256.of(expected)])
+      expectStackTop(assembly, Int256.of(expected))
     })
   })
 
@@ -44,7 +50,7 @@ describe('Memory opcodes', () => {
         PUSH1 00
         MLOAD
       `
-      expectStack(assembly, [word])
+      expectStackTop(assembly, word)
     })
 
     it('can cause stack underflow', () => {
@@ -78,7 +84,7 @@ describe('Memory opcodes', () => {
         PUSH1 00
         MLOAD
       `
-      expectStack(assembly, ['ef'.padEnd(64, '0')])
+      expectStackTop(assembly, 'ef'.padEnd(64, '0'))
     })
 
     it('can cause stack underflow', () => {
@@ -111,7 +117,7 @@ describe('Memory opcodes', () => {
         PUSH1 10
         MLOAD
       `
-      expectStack(assembly, ['e'.repeat(32) + 'b'.repeat(32)])
+      expectStackTop(assembly, 'e'.repeat(32) + 'b'.repeat(32))
     })
 
     it('can cause stack underflow', () => {
diff --git a/packages/evm/test/evm/opcodes/pop.test.ts b/packages/evm/test/opcodes/pop.test.ts
similarity index 58%
rename from packages/evm/test/evm/opcodes/pop.test.ts
rename to packages/evm/test/opcodes/pop.test.ts
index 3395aee..31aa5b5 100644
--- a/packages/evm/test/evm/opcodes/pop.test.ts
+++ b/packages/evm/test/opcodes/pop.test.ts
@@ -1,5 +1,5 @@
-import { GasCost } from '../../../src/evm/opcodes/gasCosts'
-import { Int256, expectUnderflow, expectGas, expectStack } from '../helpers'
+import { GasCost } from '../../src/opcodes/gasCosts'
+import { Int256, expectUnderflow, expectGas, expectStackTop } from '../helpers'
 
 describe('POP opcode', () => {
   it(`uses ${GasCost.BASE} gas`, () => {
@@ -7,7 +7,7 @@ describe('POP opcode', () => {
   })
 
   it('pops an item from the stack', () => {
-    expectStack('PUSH1 01 PUSH1 02 POP', [Int256.of(1)])
+    expectStackTop('PUSH1 01 PUSH1 02 POP', Int256.of(1))
   })
 
   it('can cause a stack underflow', () => {
diff --git a/packages/evm/test/evm/opcodes/push.test.ts b/packages/evm/test/opcodes/push.test.ts
similarity index 68%
rename from packages/evm/test/evm/opcodes/push.test.ts
rename to packages/evm/test/opcodes/push.test.ts
index 0cb46db..1f0b8b6 100644
--- a/packages/evm/test/evm/opcodes/push.test.ts
+++ b/packages/evm/test/opcodes/push.test.ts
@@ -1,6 +1,6 @@
-import { expectStack, expectGas, expectError } from '../helpers'
-import { GasCost } from '../../../src/evm/opcodes/gasCosts'
-import { StackOverflow } from '../../../src/evm/errors'
+import { expectStackTop, expectGas, expectError } from '../helpers'
+import { GasCost } from '../../src/opcodes/gasCosts'
+import { StackOverflow } from '../../src/errors'
 
 describe('PUSH* opcodes', () => {
   for (let n = 1; n <= 32; n++) {
@@ -10,7 +10,7 @@ describe('PUSH* opcodes', () => {
         .join('')
 
       it('pushes a value onto the stack', () => {
-        expectStack(`PUSH${n} ${bytes}`, [bytes.padStart(64, '0')])
+        expectStackTop(`PUSH${n} ${bytes}`, bytes.padStart(64, '0'))
       })
 
       it(`uses ${GasCost.VERYLOW} gas`, () => {
diff --git a/packages/evm/test/evm/opcodes/return.test.ts b/packages/evm/test/opcodes/return.test.ts
similarity index 73%
rename from packages/evm/test/evm/opcodes/return.test.ts
rename to packages/evm/test/opcodes/return.test.ts
index b215f8f..796bf2f 100644
--- a/packages/evm/test/evm/opcodes/return.test.ts
+++ b/packages/evm/test/opcodes/return.test.ts
@@ -1,10 +1,12 @@
-import { expectStack, expectReturn, expectGas, memoryGas } from '../helpers'
-import { GasCost } from '../../../src/evm/opcodes'
-import { Byte } from '../../../src/evm/Byte'
+import { expectReturn, expectGas, memoryGas, Int256, expectStorage } from '../helpers'
+import { GasCost } from '../../src/opcodes'
+import { Byte } from '../../src/Byte'
 
 describe('RETURN opcode', () => {
   it('halts execution', () => {
-    expectStack('PUSH1 00 PUSH1 00 RETURN PUSH1 01', [])
+    expectStorage('PUSH1 00 PUSH1 00 RETURN PUSH1 01 PUSH1 00 SSTORE', {
+      '00': Int256.of(0),
+    })
   })
 
   it(`uses ${GasCost.ZERO} gas`, () => {
diff --git a/packages/evm/test/evm/opcodes/revert.test.ts b/packages/evm/test/opcodes/revert.test.ts
similarity index 61%
rename from packages/evm/test/evm/opcodes/revert.test.ts
rename to packages/evm/test/opcodes/revert.test.ts
index 48e6a10..f9dba1c 100644
--- a/packages/evm/test/evm/opcodes/revert.test.ts
+++ b/packages/evm/test/opcodes/revert.test.ts
@@ -1,12 +1,8 @@
-import { expectStack, expectGas, memoryGas, expectRevert, expectStorage, Int256 } from '../helpers'
-import { GasCost } from '../../../src/evm/opcodes'
-import { Byte } from '../../../src/evm/Byte'
+import { expectGas, memoryGas, expectRevert } from '../helpers'
+import { GasCost } from '../../src/opcodes'
+import { Byte } from '../../src/Byte'
 
 describe('REVERT opcode', () => {
-  it('halts execution', () => {
-    expectStack('PUSH1 00 PUSH1 00 REVERT PUSH1 01', [])
-  })
-
   it(`uses ${GasCost.ZERO} gas`, () => {
     expectGas('PUSH1 00 PUSH1 00 REVERT', GasCost.VERYLOW * 2 + GasCost.ZERO)
   })
@@ -36,10 +32,4 @@ describe('REVERT opcode', () => {
     const gas = GasCost.VERYLOW * 2 + GasCost.ZERO + memoryGas(0x100001 + 2)
     expectGas(assembly, gas)
   })
-
-  it('reverts state changes', () => {
-    expectStorage('PUSH1 01 PUSH1 00 SSTORE PUSH1 00 DUP1 REVERT', {
-      [Int256.of(0)]: Int256.of(0),
-    })
-  })
 })
diff --git a/packages/evm/test/evm/opcodes/stop.test.ts b/packages/evm/test/opcodes/stop.test.ts
similarity index 54%
rename from packages/evm/test/evm/opcodes/stop.test.ts
rename to packages/evm/test/opcodes/stop.test.ts
index df85e7b..bb056af 100644
--- a/packages/evm/test/evm/opcodes/stop.test.ts
+++ b/packages/evm/test/opcodes/stop.test.ts
@@ -1,5 +1,5 @@
-import { GasCost } from '../../../src/evm/opcodes/gasCosts'
-import { Int256, expectGas, expectStack, expectReturn } from '../helpers'
+import { GasCost } from '../../src/opcodes/gasCosts'
+import { Int256, expectGas, expectStackTop, expectReturn } from '../helpers'
 
 describe('STOP opcode', () => {
   it(`uses ${GasCost.ZERO} gas`, () => {
@@ -7,7 +7,7 @@ describe('STOP opcode', () => {
   })
 
   it('halts execution', () => {
-    expectStack('PUSH1 00 STOP NEG', [Int256.of(0)])
+    expectStackTop('PUSH1 00 STOP NEG', Int256.of(0))
   })
 
   it('returns empty', () => {
diff --git a/packages/evm/test/evm/opcodes/storage.test.ts b/packages/evm/test/opcodes/storage.test.ts
similarity index 90%
rename from packages/evm/test/evm/opcodes/storage.test.ts
rename to packages/evm/test/opcodes/storage.test.ts
index 079a07b..6b16a3b 100644
--- a/packages/evm/test/evm/opcodes/storage.test.ts
+++ b/packages/evm/test/opcodes/storage.test.ts
@@ -1,11 +1,11 @@
-import { GasCost, GasRefund } from '../../../src/evm/opcodes'
+import { GasCost, GasRefund } from '../../src/opcodes'
 import {
   expectGas,
   expectUnderflow,
   expectStorage,
   Int256,
-  expectStack,
   expectRefund,
+  expectStackTop,
 } from '../helpers'
 
 describe('Storage opcodes', () => {
@@ -72,11 +72,11 @@ describe('Storage opcodes', () => {
     })
 
     it('can get a value from storage where it defaults to 0', () => {
-      expectStack('PUSH1 00 SLOAD', [Int256.of(0)])
+      expectStackTop('PUSH1 00 SLOAD', Int256.of(0))
     })
 
     it('can get a previously set value from storage', () => {
-      expectStack('PUSH1 01 PUSH1 00 SSTORE PUSH1 00 SLOAD', [Int256.of(1)])
+      expectStackTop('PUSH1 01 PUSH1 00 SSTORE PUSH1 00 SLOAD', Int256.of(1))
     })
   })
 })
diff --git a/packages/evm/test/evm/opcodes/swap.test.ts b/packages/evm/test/opcodes/swap.test.ts
similarity index 57%
rename from packages/evm/test/evm/opcodes/swap.test.ts
rename to packages/evm/test/opcodes/swap.test.ts
index 2666ec3..0d406ba 100644
--- a/packages/evm/test/evm/opcodes/swap.test.ts
+++ b/packages/evm/test/opcodes/swap.test.ts
@@ -1,5 +1,5 @@
-import { GasCost } from '../../../src/evm/opcodes/gasCosts'
-import { expectUnderflow, makeStack, expectStack, expectGas } from '../helpers'
+import { GasCost } from '../../src/opcodes/gasCosts'
+import { expectUnderflow, makeStack, expectStackTop, expectGas } from '../helpers'
 
 describe('SWAP* opcodes', () => {
   const stack = makeStack(17)
@@ -11,10 +11,8 @@ describe('SWAP* opcodes', () => {
   for (let n = 1; n <= 16; n++) {
     describe(`SWAP${n}`, () => {
       it('swaps the values on the stack', () => {
-        const expected = [...stack]
-        expected[expected.length - 1] = stack[expected.length - 1 - n]
-        expected[expected.length - 1 - n] = stack[expected.length - 1]
-        expectStack(`${assembly} SWAP${n}`, expected)
+        expectStackTop(`${assembly} SWAP${n}`, stack[stack.length - 1 - n])
+        expectStackTop(`${assembly} SWAP${n} POP DUP${n}`, stack[stack.length - 1])
       })
 
       it('can cause a stack underflow', () => {