class documentation

A unit test. The atom of the unit testing universe.

This class extends unittest.TestCase from the standard library. A number of convenient testing helpers are added, including logging and warning integration, monkey-patching support, and more.

To write a unit test, subclass SynchronousTestCase and define a method (say, 'test_foo') on the subclass. To run the test, instantiate your subclass with the name of the method, and call run on the instance, passing a TestResult object.

The trial script will automatically find any SynchronousTestCase subclasses defined in modules beginning with 'test_' and construct test cases for all methods beginning with 'test'.

If an error is logged during the test run, the test will fail with an error. See log.err.

Method __eq__ Override the comparison defined by the base TestCase which considers instances of the same class with the same _testMethodName to be equal. Since trial puts TestCase instances into a set, that definition of comparison makes it impossible to run the same test method twice...
Method __hash__ Undocumented
Method __init__ Undocumented
Method addCleanup Add the given function to a list of functions to be called after the test has run, but before tearDown.
Method callDeprecated Call a function that should have been deprecated at a specific version and in favor of a specific alternative, and assert that it was thusly deprecated.
Method flushLoggedErrors Remove stored errors received from the log.
Method flushWarnings Remove stored warnings from the list of captured warnings and return them.
Method getDeprecatedModuleAttribute Retrieve a module attribute which should have been deprecated, and assert that we saw the appropriate deprecation warning.
Method getSkip Return the skip reason set on this test, if any is set. Checks on the instance first, then the class, then the module, then packages. As soon as it finds something with a skip attribute, returns that in a tuple (...
Method getTodo Return a Todo object if the test is marked todo. Checks on the instance first, then the class, then the module, then packages. As soon as it finds something with a todo attribute, returns that. Returns ...
Method mktemp Create a new path name which can be used for a new file or directory.
Method patch Monkey patch an object for the duration of the test.
Method run Run the test case, storing the results in result.
Method runTest If no methodName argument is passed to the constructor, run will treat this method as the thing with the actual test inside.
Method shortDescription Undocumented
Instance Variable failureException An exception class, defaulting to FailTest. If the test method raises this exception, it will be reported as a failure, rather than an exception. All of the assertion methods raise this if the assertion fails.
Instance Variable skip None or a string explaining why this test is to be skipped. If defined, the test will not be run. Instead, it will be reported to the result object as 'skipped' (if the TestResult supports skipping).
Instance Variable suppress None or a list of tuples of (args, kwargs) to be passed to warnings.filterwarnings. Use these to suppress warnings raised in a test. Useful for testing deprecated code. See also util.suppress.
Instance Variable todo None, a string or a tuple of (errors, reason) where errors is either an exception class or an iterable of exception classes, and reason is a string. See Todo or makeTodo for more information.
Method _getSkipReason Return the reason to use for skipping a test method.
Method _getSuppress Returns any warning suppressions set for this test. Checks on the instance first, then the class, then the module, then packages. As soon as it finds something with a suppress attribute, returns that. ...
Method _installObserver Undocumented
Method _removeObserver Undocumented
Method _run Run a single method, either a test method or fixture.
Method _runCleanups Synchronously run any cleanups which have been added.
Method _runFixturesAndTest Run setUp, a test method, test cleanups, and tearDown.
Instance Variable _cleanups Undocumented
Instance Variable _observer Undocumented
Instance Variable _parents Undocumented
Instance Variable _passed Undocumented
Instance Variable _testMethodName Undocumented
Instance Variable _warnings Undocumented

Inherited from _Assertions:

Method assertAlmostEqual Fail if the two objects are unequal as determined by their difference rounded to the given number of decimal places (default 7) and comparing to zero.
Method assertApproximates Fail if first - second > tolerance
Method assertEqual Fail the test if first and second are not equal.
Method assertFalse Fail the test if condition evaluates to True.
Method assertIn Fail the test if containee is not found in container.
Method assertIs Fail the test if first is not second. This is an obect-identity-equality test, not an object equality (i.e. __eq__) test.
Method assertIsInstance Fail if instance is not an instance of the given class or of one of the given classes.
Method assertIsNot Fail the test if first is second. This is an obect-identity-equality test, not an object equality (i.e. __eq__) test.
Method assertNoResult Assert that deferred does not have a result at this point.
Method assertNotAlmostEqual Fail if the two objects are equal as determined by their difference rounded to the given number of decimal places (default 7) and comparing to zero.
Method assertNotEqual Fail the test if first == second.
Method assertNotIn Fail the test if containee is found in container.
Method assertNotIsInstance Fail if instance is an instance of the given class or of one of the given classes.
Method assertNotSubstring Fail if astring contains substring.
Method assertRaises Fail the test unless calling the function f with the given args and kwargs raises exception. The failure will report the traceback and call stack of the unexpected exception.
Method assertSubstring Fail if substring does not exist within astring.
Method assertTrue Fail the test if condition evaluates to False.
Method assertWarns Fail if the given function doesn't generate the specified warning when called. It calls the function, checks the warning, and forwards the result of the function if everything is fine.
Method fail Absolutely fail the test. Do not pass go, do not collect $200.
Method failureResultOf Return the current failure result of deferred or raise self.failureException.
Method successResultOf Return the current success result of deferred or raise self.failureException.
def __eq__(self, other: object) -> bool: (source)

Override the comparison defined by the base TestCase which considers instances of the same class with the same _testMethodName to be equal. Since trial puts TestCase instances into a set, that definition of comparison makes it impossible to run the same test method twice. Most likely, trial should stop using a set to hold tests, but until it does, this is necessary on Python 2.6. -exarkun

def __hash__(self): (source)

Undocumented

def __init__(self, methodName='runTest'): (source)

Undocumented

def addCleanup(self, f: Callable[_P, object], *args: _P.args, **kwargs: _P.kwargs): (source)

Add the given function to a list of functions to be called after the test has run, but before tearDown.

Functions will be run in reverse order of being added. This helps ensure that tear down complements set up.

As with all aspects of SynchronousTestCase, Deferreds are not supported in cleanup functions.

def callDeprecated(self, version, f, *args, **kwargs): (source)

Call a function that should have been deprecated at a specific version and in favor of a specific alternative, and assert that it was thusly deprecated.

Parameters
versionA 2-sequence of (since, replacement), where since is a the first version that f should have been deprecated since, and replacement is a suggested replacement for the deprecated functionality, as described by twisted.python.deprecate.deprecated. If there is no suggested replacement, this parameter may also be simply a version by itself.
fThe deprecated function to call.
*argsThe arguments to pass to f.
**kwargsThe keyword arguments to pass to f.
Returns
Whatever f returns.
Raises
ExceptionWhatever f raises. If any exception is raised by f, though, no assertions will be made about emitted deprecations.
FailTestif no warnings were emitted by f, or if the DeprecationWarning emitted did not produce the canonical please-use-something-else message that is standard for Twisted deprecations according to the given version and replacement.
def flushLoggedErrors(self, *errorTypes): (source)

Remove stored errors received from the log.

TestCase stores each error logged during the run of the test and reports them as errors during the cleanup phase (after tearDown).

Parameters
*errorTypesIf unspecified, flush all errors. Otherwise, only flush errors that match the given types.
Returns
A list of failures that have been removed.
def flushWarnings(self, offendingFunctions=None): (source)

Remove stored warnings from the list of captured warnings and return them.

Parameters
offendingFunctions:None or list of functions or methods.If None, all warnings issued during the currently running test will be flushed. Otherwise, only warnings which point to a function included in this list will be flushed. All warnings include a filename and source line number; if these parts of a warning point to a source line which is part of a function, then the warning points to that function.
Returns

A list, each element of which is a dict giving information about one warning which was flushed by this call. The keys of each dict are:

  • 'message': The string which was passed as the message parameter to warnings.warn.
  • 'category': The warning subclass which was passed as the category parameter to warnings.warn.
  • 'filename': The name of the file containing the definition of the code object which was stacklevel frames above the call to warnings.warn, where stacklevel is the value of the stacklevel parameter passed to warnings.warn.
  • 'lineno': The source line associated with the active instruction of the code object object which was stacklevel frames above the call to warnings.warn, where stacklevel is the value of the stacklevel parameter passed to warnings.warn.
Raises
ValueErrorIf offendingFunctions is not None and includes an object which is not a types.FunctionType or types.MethodType instance.
def getDeprecatedModuleAttribute(self, moduleName, name, version, message=None): (source)

Retrieve a module attribute which should have been deprecated, and assert that we saw the appropriate deprecation warning.

Parameters
moduleName:strFully-qualified Python name of the module containing the deprecated attribute; if called from the same module as the attributes are being deprecated in, using the __name__ global can be helpful
name:strAttribute name which we expect to be deprecated
versionThe first version that the module attribute was deprecated.
message:str(optional) The expected deprecation message for the module attribute
Returns
The given attribute from the named module
Raises
FailTestif no warnings were emitted on getattr, or if the DeprecationWarning emitted did not produce the canonical please-use-something-else message that is standard for Twisted deprecations according to the given version and replacement.
Present Since
Twisted 21.2.0
def getSkip(self) -> Tuple[bool, Optional[str]]: (source)

Return the skip reason set on this test, if any is set. Checks on the instance first, then the class, then the module, then packages. As soon as it finds something with a skip attribute, returns that in a tuple (True, str). If the skip attribute does not exist, look for __unittest_skip__ and __unittest_skip_why__ attributes which are set by the standard library unittest.skip function. Returns (False, None) if it cannot find anything. See TestCase docstring for more details.

def getTodo(self): (source)

Return a Todo object if the test is marked todo. Checks on the instance first, then the class, then the module, then packages. As soon as it finds something with a todo attribute, returns that. Returns None if it cannot find anything. See TestCase docstring for more details.

def mktemp(self): (source)

Create a new path name which can be used for a new file or directory.

The result is a relative path that is guaranteed to be unique within the current working directory. The parent of the path will exist, but the path will not.

For a temporary directory call os.mkdir on the path. For a temporary file just create the file (e.g. by opening the path for writing and then closing it).

Returns
strThe newly created path
def patch(self, obj, attribute, value): (source)

Monkey patch an object for the duration of the test.

The monkey patch will be reverted at the end of the test using the addCleanup mechanism.

The monkey.MonkeyPatcher is returned so that users can restore and re-apply the monkey patch within their tests.

Parameters
objThe object to monkey patch.
attributeThe name of the attribute to change.
valueThe value to set the attribute to.
Returns
A monkey.MonkeyPatcher object.
def run(self, result): (source)

Run the test case, storing the results in result.

First runs setUp on self, then runs the test method (defined in the constructor), then runs tearDown. As with the standard library unittest.TestCase, the return value of these methods is disregarded. In particular, returning a Deferred has no special additional consequences.

Parameters
resultA TestResult object.
def runTest(self): (source)

If no methodName argument is passed to the constructor, run will treat this method as the thing with the actual test inside.

def shortDescription(self): (source)

Undocumented

failureException = (source)

An exception class, defaulting to FailTest. If the test method raises this exception, it will be reported as a failure, rather than an exception. All of the assertion methods raise this if the assertion fails.

None or a string explaining why this test is to be skipped. If defined, the test will not be run. Instead, it will be reported to the result object as 'skipped' (if the TestResult supports skipping).

suppress = (source)

None or a list of tuples of (args, kwargs) to be passed to warnings.filterwarnings. Use these to suppress warnings raised in a test. Useful for testing deprecated code. See also util.suppress.

None, a string or a tuple of (errors, reason) where errors is either an exception class or an iterable of exception classes, and reason is a string. See Todo or makeTodo for more information.

def _getSkipReason(self, method, skip): (source)

Return the reason to use for skipping a test method.

Parameters
methodThe method which produced the skip.
skipA unittest.SkipTest instance raised by method.
def _getSuppress(self): (source)

Returns any warning suppressions set for this test. Checks on the instance first, then the class, then the module, then packages. As soon as it finds something with a suppress attribute, returns that. Returns any empty list (i.e. suppress no warnings) if it cannot find anything. See TestCase docstring for more details.

def _installObserver(self): (source)

Undocumented

def _removeObserver(self): (source)

Undocumented

def _run(self, suppress, todo, method, result): (source)

Run a single method, either a test method or fixture.

Parameters
suppressAny warnings to suppress, as defined by the suppress attribute on this method, test case, or the module it is defined in.
todoAny expected failure or failures, as defined by the todo attribute on this method, test case, or the module it is defined in.
methodThe method to run.
resultThe TestResult instance to which to report results.
Returns
True if the method fails and no further method/fixture calls should be made, False otherwise.
def _runCleanups(self, result): (source)

Synchronously run any cleanups which have been added.

def _runFixturesAndTest(self, result): (source)

Run setUp, a test method, test cleanups, and tearDown.

Parameters
resultThe TestResult instance to which to report results.
_cleanups: list = (source)

Undocumented

_observer = (source)

Undocumented

_parents = (source)

Undocumented

Undocumented

_testMethodName = (source)

Undocumented

_warnings: list = (source)

Undocumented