refactor(warnings): rework MiscalledStubWarning checker for clarity (#219)

Author: mcous

decoy/warning_checker.py

@@ -1,5 +1,7 @@
 """Warning checker."""
-from typing import Dict, List, Sequence
+from collections import defaultdict
+from itertools import groupby
+from typing import Dict, List, NamedTuple, Sequence
 from warnings import warn
 
 from .spy_events import (
@@ -8,6 +10,7 @@
     SpyEvent,
     VerifyRehearsal,
     WhenRehearsal,
+    SpyRehearsal,
     match_event,
 )
 from .warnings import DecoyWarning, MiscalledStubWarning, RedundantVerifyWarning
@@ -23,44 +26,62 @@ def check(all_calls: Sequence[AnySpyEvent]) -> None:
         _check_no_redundant_verify(all_calls)
 
 
+class _Call(NamedTuple):
+    event: SpyEvent
+    all_rehearsals: List[SpyRehearsal]
+    matching_rehearsals: List[SpyRehearsal]
+
+
 def _check_no_miscalled_stubs(all_events: Sequence[AnySpyEvent]) -> None:
     """Ensure every call matches a rehearsal, if the spy has rehearsals."""
-    all_calls_by_id: Dict[int, List[AnySpyEvent]] = {}
+    all_events_by_id: Dict[int, List[AnySpyEvent]] = defaultdict(list)
+    all_calls_by_id: Dict[int, List[_Call]] = defaultdict(list)
 
     for event in all_events:
-        if isinstance(event.payload, SpyCall):
-            spy_id = event.spy.id
-            spy_calls = all_calls_by_id.get(spy_id, [])
-            all_calls_by_id[spy_id] = [*spy_calls, event]
+        all_events_by_id[event.spy.id].append(event)
+
+    for events in all_events_by_id.values():
+        for index, event in enumerate(events):
+            if isinstance(event, SpyEvent) and isinstance(event.payload, SpyCall):
+                when_rehearsals = [
+                    rehearsal
+                    for rehearsal in events[0:index]
+                    if isinstance(rehearsal, WhenRehearsal)
+                    and isinstance(rehearsal.payload, SpyCall)
+                ]
+                verify_rehearsals = [
+                    rehearsal
+                    for rehearsal in events[index + 1 :]
+                    if isinstance(rehearsal, VerifyRehearsal)
+                    and isinstance(rehearsal.payload, SpyCall)
+                ]
+
+                all_rehearsals: List[SpyRehearsal] = [
+                    *when_rehearsals,
+                    *verify_rehearsals,
+                ]
+                matching_rehearsals = [
+                    rehearsal
+                    for rehearsal in all_rehearsals
+                    if match_event(event, rehearsal)
+                ]
+
+                all_calls_by_id[event.spy.id].append(
+                    _Call(event, all_rehearsals, matching_rehearsals)
+                )
 
     for spy_calls in all_calls_by_id.values():
-        unmatched: List[SpyEvent] = []
-
-        for index, call in enumerate(spy_calls):
-            past_stubs = [
-                wr for wr in spy_calls[0:index] if isinstance(wr, WhenRehearsal)
-            ]
-
-            matched_past_stubs = [wr for wr in past_stubs if match_event(call, wr)]
-
-            matched_future_verifies = [
-                vr
-                for vr in spy_calls[index + 1 :]
-                if isinstance(vr, VerifyRehearsal) and match_event(call, vr)
-            ]
-
-            if (
-                isinstance(call, SpyEvent)
-                and len(past_stubs) > 0
-                and len(matched_past_stubs) == 0
-                and len(matched_future_verifies) == 0
-            ):
-                unmatched = [*unmatched, call]
-                if index == len(spy_calls) - 1:
-                    _warn(MiscalledStubWarning(calls=unmatched, rehearsals=past_stubs))
-            elif isinstance(call, WhenRehearsal) and len(unmatched) > 0:
-                _warn(MiscalledStubWarning(calls=unmatched, rehearsals=past_stubs))
-                unmatched = []
+        for rehearsals, grouped_calls in groupby(spy_calls, lambda c: c.all_rehearsals):
+            calls = list(grouped_calls)
+            is_stubbed = any(isinstance(r, WhenRehearsal) for r in rehearsals)
+
+            if is_stubbed and all(len(c.matching_rehearsals) == 0 for c in calls):
+                _warn(
+                    MiscalledStubWarning(
+                        calls=[c.event for c in calls],
+                        rehearsals=rehearsals,
+                    )
+                )
 
 
 def _check_no_redundant_verify(all_calls: Sequence[AnySpyEvent]) -> None:

decoy/warnings.py

@@ -7,7 +7,7 @@
 import os
 from typing import Sequence
 
-from .spy_events import SpyEvent, WhenRehearsal, VerifyRehearsal
+from .spy_events import SpyEvent, SpyRehearsal, VerifyRehearsal
 from .stringify import stringify_call, stringify_error_message, count
 
 
@@ -34,12 +34,12 @@ class MiscalledStubWarning(DecoyWarning):
         calls: Actual calls to the mock.
     """
 
-    rehearsals: Sequence[WhenRehearsal]
+    rehearsals: Sequence[SpyRehearsal]
     calls: Sequence[SpyEvent]
 
     def __init__(
         self,
-        rehearsals: Sequence[WhenRehearsal],
+        rehearsals: Sequence[SpyRehearsal],
         calls: Sequence[SpyEvent],
     ) -> None:
         heading = os.linesep.join(

tests/test_call_handler.py

@@ -21,11 +21,7 @@ def stub_store(decoy: Decoy) -> StubStore:
 
 
 @pytest.fixture()
-def subject(
-    decoy: Decoy,
-    spy_log: SpyLog,
-    stub_store: StubStore,
-) -> CallHandler:
+def subject(spy_log: SpyLog, stub_store: StubStore) -> CallHandler:
     """Get a CallHandler instance with its dependencies mocked out."""
     return CallHandler(
         spy_log=spy_log,
@@ -98,7 +94,6 @@ def test_handle_call_with_raise(
 
 def test_handle_call_with_action(
     decoy: Decoy,
-    spy_log: SpyLog,
     stub_store: StubStore,
     subject: CallHandler,
 ) -> None:
@@ -120,7 +115,6 @@ def test_handle_call_with_action(
 
 def test_handle_prop_get_with_action(
     decoy: Decoy,
-    spy_log: SpyLog,
     stub_store: StubStore,
     subject: CallHandler,
 ) -> None: