Show diff when API calls have changed (#3646)

* Show diff when API calls have changed

* Format code

---------

Co-authored-by: Joakim Sørensen <[email protected]>

tests/conftest.py

@@ -12,6 +12,7 @@
 from typing import Any, Generator
 from unittest.mock import MagicMock, patch
 
+from _pytest.assertion.util import _compare_eq_iterable
 from awesomeversion import AwesomeVersion
 import freezegun
 from homeassistant import loader
@@ -418,4 +419,20 @@ def pytest_sessionfinish(session: pytest.Session, exitstatus: int):
     with open("tests/output/proxy_calls.json", encoding="utf-8") as file:
         current = json.load(file)
         if current != filtered_calls:
-            raise AssertionError("API calls have changed, run scripts/snapshot-update")
+            diff = ""
+            for test in current:
+                if test not in filtered_calls:
+                    diff += f"Test '{test}' was removed\n"
+            for test in filtered_calls:
+                if test not in current:
+                    diff += f"Test '{test}' was added\n"
+            for test in filtered_calls:
+                if test not in current:
+                    continue
+                if filtered_calls[test] == current[test]:
+                    continue
+                diff += f"Test '{test}' has changed\n"
+                diff += "\n".join(_compare_eq_iterable(filtered_calls[test], current[test], 3))
+                diff += "\n"
+
+            raise AssertionError(f"API calls have changed, run scripts/snapshot-update\n{diff}")