feat: add decoy.next preview API

Author: mcous

decoy/errors.py

@@ -25,6 +25,10 @@ def create(cls) -> "MockNameRequiredError":
         return cls("Mocks without `cls` or `func` require a `name`.")
 
 
+class MockSpecInvalidError(TypeError):
+    """An value passed as a mock spec is not valid."""
+
+
 class MissingRehearsalError(ValueError):
     """An error raised when a Decoy method is called without rehearsal(s).
 
@@ -44,6 +48,14 @@ def create(cls) -> "MissingRehearsalError":
         return cls("Rehearsal not found.")
 
 
+class NotAMockError(TypeError):
+    """A Decoy method was called without a mock."""
+
+
+class ThenDoActionNotCallableError(TypeError):
+    """A value passed to `then_do` is not callable."""
+
+
 class MockNotAsyncError(TypeError):
     """An error raised when an asynchronous function is used with a synchronous mock.
 
@@ -55,6 +67,10 @@ class MockNotAsyncError(TypeError):
     """
 
 
+class SignatureMismatchError(TypeError):
+    """Arguments did not match the signature of the mock."""
+
+
 class VerifyError(AssertionError):
     """An error raised when actual calls do not match rehearsals given to `verify`.
 
@@ -100,3 +116,12 @@ def create(
         result.times = times
 
         return result
+
+
+class VerifyOrderError(VerifyError):
+    """An error raised when the order of calls do not match expectations.
+
+    See [spying with verify][] for more details.
+
+    [spying with verify]: usage/verify.md
+    """

decoy/next/__init__.py

@@ -0,0 +1,19 @@
+"""Decoy mocking library.
+
+Use Decoy to create stubs and spies
+to isolate your code under test.
+"""
+
+from ._internal.decoy import Decoy
+from ._internal.mock import AsyncMock, Mock
+from ._internal.verify import Verify
+from ._internal.when import Stub, When
+
+__all__ = [
+    "AsyncMock",
+    "Decoy",
+    "Mock",
+    "Stub",
+    "Verify",
+    "When",
+]

decoy/next/_internal/__init__.py

@@ -0,0 +1,138 @@
+from .values import (
+    AttributeEvent,
+    AttributeEventType,
+    BehaviorEntry,
+    CallEvent,
+    Event,
+    EventEntry,
+    EventMatcher,
+    EventState,
+    MockInfo,
+    VerificationEntry,
+)
+
+
+def is_event_from_mock(event_entry: EventEntry, mock: MockInfo) -> bool:
+    return mock.id == event_entry.mock.id
+
+
+def is_verifiable_mock_event(event_entry: EventEntry, mock: MockInfo) -> bool:
+    return is_event_from_mock(event_entry, mock) and (
+        isinstance(event_entry.event, CallEvent)
+        or event_entry.event.type != AttributeEventType.GET
+    )
+
+
+def is_matching_behavior(
+    event_entry: EventEntry,
+    behavior_entry: BehaviorEntry,
+) -> bool:
+    return is_event_from_mock(
+        event_entry,
+        behavior_entry.mock,
+    ) and is_matching_event(
+        event_entry,
+        behavior_entry.matcher,
+    )
+
+
+def is_matching_event(event_entry: EventEntry, matcher: EventMatcher) -> bool:
+    event_matches = _match_event(event_entry.event, matcher)
+    state_matches = _match_state(event_entry.state, matcher)
+
+    return event_matches and state_matches
+
+
+def is_matching_count(usage_count: int, matcher: EventMatcher) -> bool:
+    return matcher.options.times is None or usage_count < matcher.options.times
+
+
+def is_successful_verify(verification: VerificationEntry) -> bool:
+    if verification.matcher.options.times is not None:
+        return len(verification.matching_events) == verification.matcher.options.times
+
+    return len(verification.matching_events) > 0
+
+
+def is_successful_verify_order(verifications: list[VerificationEntry]) -> bool:
+    matching_events: list[tuple[EventEntry, VerificationEntry]] = []
+    verification_index = 0
+    event_index = 0
+
+    for verification in verifications:
+        for matching_event in verification.matching_events:
+            matching_events.append((matching_event, verification))
+
+    matching_events.sort(key=lambda e: e[0].order)
+
+    while event_index < len(matching_events) and verification_index < len(
+        verifications
+    ):
+        _, event_verification = matching_events[event_index]
+        expected_verification = verifications[verification_index]
+        expected_times = expected_verification.matcher.options.times
+        remaining_events = len(matching_events) - event_index
+
+        if event_verification is expected_verification:
+            verification_index += 1
+
+            if expected_times is None or expected_times == 1:
+                event_index += 1
+            else:
+                for times_index in range(1, expected_times):
+                    _, later_verification = matching_events[event_index + times_index]
+                    if later_verification is not expected_verification:
+                        return False
+
+                event_index += expected_times
+
+        elif remaining_events >= len(verifications) and verification_index > 0:
+            verification_index = 0
+        else:
+            return False
+
+    return True
+
+
+def is_redundant_verify(
+    verification: VerificationEntry,
+    behaviors: list[BehaviorEntry],
+) -> bool:
+    return any(
+        behavior
+        for behavior in behaviors
+        if verification.mock.id == behavior.mock.id
+        and verification.matcher.options == behavior.matcher.options
+        and _match_event(verification.matcher.event, behavior.matcher)
+    )
+
+
+def _match_event(event: Event, matcher: EventMatcher) -> bool:
+    if (
+        matcher.options.ignore_extra_args is False
+        or isinstance(event, AttributeEvent)
+        or isinstance(matcher.event, AttributeEvent)
+    ):
+        return event == matcher.event
+
+    try:
+        args_match = all(
+            value == event.args[i] for i, value in enumerate(matcher.event.args)
+        )
+        kwargs_match = all(
+            value == event.kwargs[key] for key, value in matcher.event.kwargs.items()
+        )
+
+        return args_match and kwargs_match
+
+    except (IndexError, KeyError):
+        pass
+
+    return False
+
+
+def _match_state(event_state: EventState, matcher: EventMatcher) -> bool:
+    return (
+        matcher.options.is_entered is None
+        or event_state.is_entered == matcher.options.is_entered
+    )