def test_raises_type_errors(expected_exception, update,
snapshot: Snapshot):
""" Test that `Snapshot.raises` rejects invalid argument types. """
# Arrange
# Act & Assert
with pytest.raises(TypeError):
snapshot.raises(expected_exception, update=update)
def _snapshot(config: Config, metadata: SnapshotMetadata) -> Snapshot:
""" Returns a snappiershot.snapshot.Snapshot object with preset
_metadata and _snapshot_file attributes.
"""
snapshot = Snapshot()
snapshot._metadata = metadata
snapshot._snapshot_file = _SnapshotFile(config=config, metadata=metadata)
snapshot._within_context = True
return snapshot
def test_not_within_context(mocker: MockerFixture):
""" Test that an error is raised when trying to call the `Snapshot.assert_match`
method outside of context. """
# Arrange
snapshot = Snapshot()
# Safety mock, should not get called.
mocker.patch.object(snapshot,
"_get_metadata",
side_effect=EnvironmentError)
# Act & Assert
with pytest.raises(RuntimeError):
snapshot.assert_match(True)
def test_snapshot_assert_failure(snapshot: Snapshot,
mocker: MockerFixture) -> None:
""" Checks that snapshot assert works as expected with mis-matched values"""
# Arrange
# Mock stored snapshot value
value = {"balloons": "are awesome"}
mocker.patch.object(snapshot._snapshot_file,
"get_snapshot",
return_value=value)
bad_value = {"balloons": "are not awesome"}
# Act / Assert
with pytest.raises(AssertionError):
snapshot.assert_match(value=bad_value)
def test_snapshot_assert(snapshot: Snapshot,
mocker: MockerFixture) -> None:
""" Checks that snapshot assert works as expected """
# Arrange
# Mock stored snapshot value
value = {"balloons": "are awesome"}
mocker.patch.object(snapshot._snapshot_file,
"get_snapshot",
return_value=value)
# Act
result = snapshot.assert_match(value=value)
# Assert
assert result
def test_raises_match(snapshot: Snapshot, mocker: MockerFixture):
""" Test that `Snapshot.raises` catches and snapshot exceptions as expected. """
# Arrange
exception = ZeroDivisionError("Whoops")
value = encode_exception(exception)
mocker.patch.object(snapshot._snapshot_file,
"get_snapshot",
return_value=value)
# Act
with snapshot.raises(type(exception)) as raises:
raise exception
# Assert
assert raises._assert_match
def test_construct_diff(mocker: MockerFixture):
""" Test that the human-readable diff is constructed as expected. """
# Arrange
value = False
expected = 3 + 4j
comparison = mocker.MagicMock()
summary_message = "Types not equal: <class 'bool'> != <class 'complex'>"
comparison.differences.items = dict(msg=summary_message)
expected_diff = f"""
- False
+ (3+4j)
------------------------------------------------------------------------------
Summary:
> {summary_message}
""".lstrip("\n") # Strip the newline from the start.
# Act
result = Snapshot._construct_diff(value, expected, comparison)
# Assert
assert result == expected_diff
def test_snapshot_update(snapshot: Snapshot, mocker: MockerFixture,
warning_catcher: List[WarningMessage]) -> None:
""" Checks that snapshot assert with update flag ON works as expected.
If "update" is flagged, then no AssertionError should be raised.
"""
# Arrange
# Mock stored snapshot value
value = {"balloons": "are awesome"}
mocker.patch.object(snapshot._snapshot_file,
"get_snapshot",
return_value=value)
new_value = {"balloons": "are not awesome"}
# Act
result = snapshot.assert_match(value=new_value, update=True)
# Assert
assert result
assert warning_catcher
assert warning_catcher[0].category == SnappierShotWarning