Chore/usdc decimals (#236)

* chore/fix-usdc-decimals

* fix: lint

contracts/mocks/MockUSDC.sol

@@ -0,0 +1,21 @@
+pragma solidity ^0.8.0;
+
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+
+/**
+ * @title    Token
+ * @dev      Creates a mock USDC contract just for the internal ETH network testing
+ */
+contract MockUSDC is ERC20 {
+    constructor(
+        string memory name,
+        string memory symbol,
+        uint256 mintAmount
+    ) ERC20(name, symbol) {
+        _mint(msg.sender, mintAmount);
+    }
+
+    function decimals() public view override returns (uint8) {
+        return 6;
+    }
+}

scripts/deploy_contracts.py

@@ -4,7 +4,7 @@
 
 sys.path.append(os.path.abspath("tests"))
 from consts import *
-from brownie import chain, accounts, KeyManager, Vault, StakeManager, FLIP, Token
+from brownie import chain, accounts, KeyManager, Vault, StakeManager, FLIP, MockUSDC
 from deploy import deploy_set_Chainflip_contracts, deploy_usdc_contract
 
 
@@ -35,9 +35,9 @@ def main():
 
     # Deploy USDC mimic token only on private ETH network
     if chain.id == 10997:
-        cf.usdc = deploy_usdc_contract(DEPLOYER, Token, cf_accs[0:10])
-        print(f"USDC: {cf.usdc.address}")
-        addressDump["USDC_ADDRESS"] = cf.usdc.address
+        cf.mockUSDC = deploy_usdc_contract(DEPLOYER, MockUSDC, cf_accs[0:10])
+        print(f"USDC: {cf.mockUSDC.address}")
+        addressDump["USDC_ADDRESS"] = cf.mockUSDC.address
 
     if DEPLOY_ARTEFACT_ID:
         json_content = json.dumps(addressDump)

tests/deploy.py

@@ -94,12 +94,12 @@ def deploy_set_Chainflip_contracts(
 
 
 # Deploy USDC mimic token (standard ERC20) and transfer init amount to several accounts.
-def deploy_usdc_contract(deployer, Token, accounts):
+def deploy_usdc_contract(deployer, MockUSDC, accounts):
 
-    usdc = deployer.deploy(Token, "USD Coin", "USDC", INIT_USDC_SUPPLY)
+    mockUsdc = deployer.deploy(MockUSDC, "USD Coin", "USDC", INIT_USDC_SUPPLY)
     # Distribute tokens to other accounts
     for account in accounts:
-        if account != deployer and usdc.balanceOf(deployer) >= INIT_USDC_ACCOUNT:
-            usdc.transfer(account, INIT_USDC_ACCOUNT, {"from": deployer})
+        if account != deployer and mockUsdc.balanceOf(deployer) >= INIT_USDC_ACCOUNT:
+            mockUsdc.transfer(account, INIT_USDC_ACCOUNT, {"from": deployer})
 
-    return usdc
+    return mockUsdc