test: add simple Handlers.on_block test

test/integration/fork_choice/handlers_test.exs

@@ -0,0 +1,29 @@
+defmodule Integration.ForkChoice.HandlersTest do
+  use ExUnit.Case
+
+  alias LambdaEthereumConsensus.ForkChoice.Handlers
+  alias LambdaEthereumConsensus.ForkChoice.Helpers
+  alias LambdaEthereumConsensus.Store.BlockStore
+  alias LambdaEthereumConsensus.Store.Db
+  alias LambdaEthereumConsensus.Store.StateStore
+
+  setup_all do
+    start_supervised!(Db)
+    :ok
+  end
+
+  @tag :skip
+  test "on_block w/data from DB" do
+    # NOTE: this test requires a DB with a state, and blocks for the state's slot and the next slot.
+    # WARN: sometimes fails with "OffsetOutOfBounds" errors. Re-run the test in those cases.
+    {:ok, state} = StateStore.get_latest_state()
+
+    {:ok, signed_block} = BlockStore.get_block_by_slot(state.slot)
+    {:ok, new_signed_block} = BlockStore.get_block_by_slot(state.slot + 1)
+
+    assert {:ok, store} = Helpers.get_forkchoice_store(state, signed_block.message)
+    new_store = Handlers.on_tick(store, :os.system_time(:second))
+
+    assert {:ok, _} = Handlers.on_block(new_store, new_signed_block)
+  end
+end