test: Add a logs expectation to the state_transition fixture

The state_transition fixture could assert state, gas, and trace, but not emitted logs. Add an
optional Expectation::logs, compared field-by-field (count, address, data, topics, and order) in
the runner, with a LOG1 smoke test pinning the mechanism.

Author: chfast

test/unittests/state_transition.cpp

@@ -88,6 +88,17 @@ void state_transition::TearDown()
         {
             EXPECT_EQ(receipt.gas_refund, *expect.gas_refund);
         }
+        if (expect.logs.has_value())
+        {
+            ASSERT_EQ(receipt.logs.size(), expect.logs->size()) << "unexpected number of logs";
+            for (size_t i = 0; i < expect.logs->size(); ++i)
+            {
+                EXPECT_EQ(receipt.logs[i].addr, (*expect.logs)[i].addr) << "log " << i << " addr";
+                EXPECT_EQ(receipt.logs[i].data, (*expect.logs)[i].data) << "log " << i << " data";
+                EXPECT_EQ(receipt.logs[i].topics, (*expect.logs)[i].topics)
+                    << "log " << i << " topics";
+            }
+        }
         // Update default expectations - valid transaction means coinbase exists unless explicitly
         // requested otherwise
         if (!expect.post.contains(Coinbase))

test/unittests/state_transition.hpp

@@ -62,6 +62,10 @@ class state_transition : public ExportableFixture
         /// (`gas_used + gas_refund` equals `max(pre-refund gas, EIP-7623 floor)`).
         std::optional<int64_t> gas_refund;
 
+        /// The expected logs emitted by the transaction. When set, the receipt's logs must match
+        /// exactly: count, address, data, topics, and order.
+        std::optional<std::vector<Log>> logs;
+
         /// The expected post-execution state.
         std::unordered_map<address, ExpectedAccount> post;
 

test/unittests/state_transition_tx_test.cpp

@@ -268,3 +268,15 @@ TEST_F(state_transition, invalid_access_list_amsterdam_gas_limit_below_floor)
     tx.gas_limit = 28679;
     expect.tx_error = INTRINSIC_GAS_TOO_LOW;
 }
+
+TEST_F(state_transition, tx_emits_log)
+{
+    // Smoke test for the `expect.logs` mechanism: assert a log with data and a topic from LOG1.
+    static constexpr auto TOPIC = 0xaa_bytes32;
+    tx.to = To;
+    // Store 0xaabbccdd at mem[28..31], then LOG1(offset=28, size=4, TOPIC) over those bytes.
+    pre[To] = {.code = mstore(0, 0xaabbccdd) + push(TOPIC) + push(4) + push(28) + OP_LOG1};
+
+    expect.post[To] = {};  // the contract survives (has code).
+    expect.logs = {Log{To, bytes{0xaa, 0xbb, 0xcc, 0xdd}, {TOPIC}}};
+}