Fix parsing of logs with zero topics

.github/workflows/pull_request.yaml

@@ -26,4 +26,6 @@ jobs:
       - name: Type Check (mypy)
         run: mypy src
       - name: Tests
-        run: pytest tests/e2e/test_blockchain_data.py
+        run: pytest tests/e2e/test_blockchain_data.py tests/e2e/test_imbalances_script.py
+        env:
+          NODE_URL: ${{ secrets.NODE_URL }}

src/imbalances_script.py

@@ -151,14 +151,15 @@ def extract_events(self, tx_receipt: dict) -> dict[str, list[dict]]:
 
         events: dict[str, list[dict]] = {name: [] for name in EVENT_TOPICS}
         for log in tx_receipt["logs"]:
-            log_topic = log["topics"][0].hex()
-            if log_topic in transfer_topics.values():
-                events["Transfer"].append(log)
-            else:
-                for event_name, topic in other_topics.items():
-                    if log_topic == topic:
-                        events[event_name].append(log)
-                        break
+            if log["topics"]:
+                log_topic = log["topics"][0].hex()
+                if log_topic in transfer_topics.values():
+                    events["Transfer"].append(log)
+                else:
+                    for event_name, topic in other_topics.items():
+                        if log_topic == topic:
+                            events[event_name].append(log)
+                            break
         return events
 
     def decode_event(self, event: dict) -> tuple[str | None, str | None, int | None]:

tests/e2e/test_imbalances_script.py

@@ -0,0 +1,37 @@
+from os import getenv, environ
+from unittest.mock import Mock, patch
+
+import pytest
+from web3 import Web3
+
+
+@pytest.fixture()
+def set_env_variables(monkeypatch):
+    with patch.dict(environ, clear=True):
+        envvars = {
+            "CHAIN_SLEEP_TIME": "1",
+        }
+        for k, v in envvars.items():
+            monkeypatch.setenv(k, v)
+        yield  # This is the magical bit which restore the environment after
+
+
+def tests_process_single_transaction(set_env_variables):
+    # import has to happen after patching environment variable
+    from src.imbalances_script import RawTokenImbalances
+
+    web3 = Web3(Web3.HTTPProvider(getenv("NODE_URL")))
+    raw_imbalances = RawTokenImbalances(web3, "mainnet")
+    imbalances = raw_imbalances.compute_imbalances(
+        "0xb75e03b63d4f06c56549effd503e1e37f3ccfc3c00e6985a5aacc9b0534d7c5c"
+    )
+
+    assert imbalances == {
+        "0x72e4f9F808C49A2a61dE9C5896298920Dc4EEEa9": 3116463005,
+        "0x7Fc66500c84A76Ad7e9c93437bFc5Ac33E2DDaE9": 31552225710415395,
+        "0x812Ba41e071C7b7fA4EBcFB62dF5F45f6fA853Ee": 0,
+        "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48": 0,
+        "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2": 0,
+        "0xEE2a03Aa6Dacf51C18679C516ad5283d8E7C2637": 275548164523,
+        "0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE": 0,
+    }