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@@ -0,0 +1,941 @@
+
+:mod:`unittest` --- Unit testing framework
+==========================================
+
+.. module:: unittest
+ :synopsis: Unit testing framework for Python.
+.. moduleauthor:: Steve Purcell <stephen_purcell@yahoo.com>
+.. sectionauthor:: Steve Purcell <stephen_purcell@yahoo.com>
+.. sectionauthor:: Fred L. Drake, Jr. <fdrake@acm.org>
+.. sectionauthor:: Raymond Hettinger <python@rcn.com>
+
+
+.. versionadded:: 2.1
+
+The Python unit testing framework, sometimes referred to as "PyUnit," is a
+Python language version of JUnit, by Kent Beck and Erich Gamma. JUnit is, in
+turn, a Java version of Kent's Smalltalk testing framework. Each is the de
+facto standard unit testing framework for its respective language.
+
+:mod:`unittest` supports test automation, sharing of setup and shutdown code for
+tests, aggregation of tests into collections, and independence of the tests from
+the reporting framework. The :mod:`unittest` module provides classes that make
+it easy to support these qualities for a set of tests.
+
+To achieve this, :mod:`unittest` supports some important concepts:
+
+test fixture
+ A :dfn:`test fixture` represents the preparation needed to perform one or more
+ tests, and any associate cleanup actions. This may involve, for example,
+ creating temporary or proxy databases, directories, or starting a server
+ process.
+
+test case
+ A :dfn:`test case` is the smallest unit of testing. It checks for a specific
+ response to a particular set of inputs. :mod:`unittest` provides a base class,
+ :class:`TestCase`, which may be used to create new test cases.
+
+test suite
+ A :dfn:`test suite` is a collection of test cases, test suites, or both. It is
+ used to aggregate tests that should be executed together.
+
+test runner
+ A :dfn:`test runner` is a component which orchestrates the execution of tests
+ and provides the outcome to the user. The runner may use a graphical interface,
+ a textual interface, or return a special value to indicate the results of
+ executing the tests.
+
+The test case and test fixture concepts are supported through the
+:class:`TestCase` and :class:`FunctionTestCase` classes; the former should be
+used when creating new tests, and the latter can be used when integrating
+existing test code with a :mod:`unittest`\ -driven framework. When building test
+fixtures using :class:`TestCase`, the :meth:`setUp` and :meth:`tearDown` methods
+can be overridden to provide initialization and cleanup for the fixture. With
+:class:`FunctionTestCase`, existing functions can be passed to the constructor
+for these purposes. When the test is run, the fixture initialization is run
+first; if it succeeds, the cleanup method is run after the test has been
+executed, regardless of the outcome of the test. Each instance of the
+:class:`TestCase` will only be used to run a single test method, so a new
+fixture is created for each test.
+
+Test suites are implemented by the :class:`TestSuite` class. This class allows
+individual tests and test suites to be aggregated; when the suite is executed,
+all tests added directly to the suite and in "child" test suites are run.
+
+A test runner is an object that provides a single method, :meth:`run`, which
+accepts a :class:`TestCase` or :class:`TestSuite` object as a parameter, and
+returns a result object. The class :class:`TestResult` is provided for use as
+the result object. :mod:`unittest` provides the :class:`TextTestRunner` as an
+example test runner which reports test results on the standard error stream by
+default. Alternate runners can be implemented for other environments (such as
+graphical environments) without any need to derive from a specific class.
+
+
+.. seealso::
+
+ Module :mod:`doctest`
+ Another test-support module with a very different flavor.
+
+ `Simple Smalltalk Testing: With Patterns <http://www.XProgramming.com/testfram.htm>`_
+ Kent Beck's original paper on testing frameworks using the pattern shared by
+ :mod:`unittest`.
+
+
+.. _unittest-minimal-example:
+
+Basic example
+-------------
+
+The :mod:`unittest` module provides a rich set of tools for constructing and
+running tests. This section demonstrates that a small subset of the tools
+suffice to meet the needs of most users.
+
+Here is a short script to test three functions from the :mod:`random` module::
+
+ import random
+ import unittest
+
+ class TestSequenceFunctions(unittest.TestCase):
+
+ def setUp(self):
+ self.seq = range(10)
+
+ def testshuffle(self):
+ # make sure the shuffled sequence does not lose any elements
+ random.shuffle(self.seq)
+ self.seq.sort()
+ self.assertEqual(self.seq, range(10))
+
+ def testchoice(self):
+ element = random.choice(self.seq)
+ self.assert_(element in self.seq)
+
+ def testsample(self):
+ self.assertRaises(ValueError, random.sample, self.seq, 20)
+ for element in random.sample(self.seq, 5):
+ self.assert_(element in self.seq)
+
+ if __name__ == '__main__':
+ unittest.main()
+
+A testcase is created by subclassing :class:`unittest.TestCase`. The three
+individual tests are defined with methods whose names start with the letters
+``test``. This naming convention informs the test runner about which methods
+represent tests.
+
+The crux of each test is a call to :meth:`assertEqual` to check for an expected
+result; :meth:`assert_` to verify a condition; or :meth:`assertRaises` to verify
+that an expected exception gets raised. These methods are used instead of the
+:keyword:`assert` statement so the test runner can accumulate all test results
+and produce a report.
+
+When a :meth:`setUp` method is defined, the test runner will run that method
+prior to each test. Likewise, if a :meth:`tearDown` method is defined, the test
+runner will invoke that method after each test. In the example, :meth:`setUp`
+was used to create a fresh sequence for each test.
+
+The final block shows a simple way to run the tests. :func:`unittest.main`
+provides a command line interface to the test script. When run from the command
+line, the above script produces an output that looks like this::
+
+ ...
+ ----------------------------------------------------------------------
+ Ran 3 tests in 0.000s
+
+ OK
+
+Instead of :func:`unittest.main`, there are other ways to run the tests with a
+finer level of control, less terse output, and no requirement to be run from the
+command line. For example, the last two lines may be replaced with::
+
+ suite = unittest.TestLoader().loadTestsFromTestCase(TestSequenceFunctions)
+ unittest.TextTestRunner(verbosity=2).run(suite)
+
+Running the revised script from the interpreter or another script produces the
+following output::
+
+ testchoice (__main__.TestSequenceFunctions) ... ok
+ testsample (__main__.TestSequenceFunctions) ... ok
+ testshuffle (__main__.TestSequenceFunctions) ... ok
+
+ ----------------------------------------------------------------------
+ Ran 3 tests in 0.110s
+
+ OK
+
+The above examples show the most commonly used :mod:`unittest` features which
+are sufficient to meet many everyday testing needs. The remainder of the
+documentation explores the full feature set from first principles.
+
+
+.. _organizing-tests:
+
+Organizing test code
+--------------------
+
+The basic building blocks of unit testing are :dfn:`test cases` --- single
+scenarios that must be set up and checked for correctness. In :mod:`unittest`,
+test cases are represented by instances of :mod:`unittest`'s :class:`TestCase`
+class. To make your own test cases you must write subclasses of
+:class:`TestCase`, or use :class:`FunctionTestCase`.
+
+An instance of a :class:`TestCase`\ -derived class is an object that can
+completely run a single test method, together with optional set-up and tidy-up
+code.
+
+The testing code of a :class:`TestCase` instance should be entirely self
+contained, such that it can be run either in isolation or in arbitrary
+combination with any number of other test cases.
+
+The simplest :class:`TestCase` subclass will simply override the :meth:`runTest`
+method in order to perform specific testing code::
+
+ import unittest
+
+ class DefaultWidgetSizeTestCase(unittest.TestCase):
+ def runTest(self):
+ widget = Widget('The widget')
+ self.assertEqual(widget.size(), (50, 50), 'incorrect default size')
+
+Note that in order to test something, we use the one of the :meth:`assert\*` or
+:meth:`fail\*` methods provided by the :class:`TestCase` base class. If the
+test fails, an exception will be raised, and :mod:`unittest` will identify the
+test case as a :dfn:`failure`. Any other exceptions will be treated as
+:dfn:`errors`. This helps you identify where the problem is: :dfn:`failures` are
+caused by incorrect results - a 5 where you expected a 6. :dfn:`Errors` are
+caused by incorrect code - e.g., a :exc:`TypeError` caused by an incorrect
+function call.
+
+The way to run a test case will be described later. For now, note that to
+construct an instance of such a test case, we call its constructor without
+arguments::
+
+ testCase = DefaultWidgetSizeTestCase()
+
+Now, such test cases can be numerous, and their set-up can be repetitive. In
+the above case, constructing a :class:`Widget` in each of 100 Widget test case
+subclasses would mean unsightly duplication.
+
+Luckily, we can factor out such set-up code by implementing a method called
+:meth:`setUp`, which the testing framework will automatically call for us when
+we run the test::
+
+ import unittest
+
+ class SimpleWidgetTestCase(unittest.TestCase):
+ def setUp(self):
+ self.widget = Widget('The widget')
+
+ class DefaultWidgetSizeTestCase(SimpleWidgetTestCase):
+ def runTest(self):
+ self.failUnless(self.widget.size() == (50,50),
+ 'incorrect default size')
+
+ class WidgetResizeTestCase(SimpleWidgetTestCase):
+ def runTest(self):
+ self.widget.resize(100,150)
+ self.failUnless(self.widget.size() == (100,150),
+ 'wrong size after resize')
+
+If the :meth:`setUp` method raises an exception while the test is running, the
+framework will consider the test to have suffered an error, and the
+:meth:`runTest` method will not be executed.
+
+Similarly, we can provide a :meth:`tearDown` method that tidies up after the
+:meth:`runTest` method has been run::
+
+ import unittest
+
+ class SimpleWidgetTestCase(unittest.TestCase):
+ def setUp(self):
+ self.widget = Widget('The widget')
+
+ def tearDown(self):
+ self.widget.dispose()
+ self.widget = None
+
+If :meth:`setUp` succeeded, the :meth:`tearDown` method will be run whether
+:meth:`runTest` succeeded or not.
+
+Such a working environment for the testing code is called a :dfn:`fixture`.
+
+Often, many small test cases will use the same fixture. In this case, we would
+end up subclassing :class:`SimpleWidgetTestCase` into many small one-method
+classes such as :class:`DefaultWidgetSizeTestCase`. This is time-consuming and
+discouraging, so in the same vein as JUnit, :mod:`unittest` provides a simpler
+mechanism::
+
+ import unittest
+
+ class WidgetTestCase(unittest.TestCase):
+ def setUp(self):
+ self.widget = Widget('The widget')
+
+ def tearDown(self):
+ self.widget.dispose()
+ self.widget = None
+
+ def testDefaultSize(self):
+ self.failUnless(self.widget.size() == (50,50),
+ 'incorrect default size')
+
+ def testResize(self):
+ self.widget.resize(100,150)
+ self.failUnless(self.widget.size() == (100,150),
+ 'wrong size after resize')
+
+Here we have not provided a :meth:`runTest` method, but have instead provided
+two different test methods. Class instances will now each run one of the
+:meth:`test\*` methods, with ``self.widget`` created and destroyed separately
+for each instance. When creating an instance we must specify the test method it
+is to run. We do this by passing the method name in the constructor::
+
+ defaultSizeTestCase = WidgetTestCase('testDefaultSize')
+ resizeTestCase = WidgetTestCase('testResize')
+
+Test case instances are grouped together according to the features they test.
+:mod:`unittest` provides a mechanism for this: the :dfn:`test suite`,
+represented by :mod:`unittest`'s :class:`TestSuite` class::
+
+ widgetTestSuite = unittest.TestSuite()
+ widgetTestSuite.addTest(WidgetTestCase('testDefaultSize'))
+ widgetTestSuite.addTest(WidgetTestCase('testResize'))
+
+For the ease of running tests, as we will see later, it is a good idea to
+provide in each test module a callable object that returns a pre-built test
+suite::
+
+ def suite():
+ suite = unittest.TestSuite()
+ suite.addTest(WidgetTestCase('testDefaultSize'))
+ suite.addTest(WidgetTestCase('testResize'))
+ return suite
+
+or even::
+
+ def suite():
+ tests = ['testDefaultSize', 'testResize']
+
+ return unittest.TestSuite(map(WidgetTestCase, tests))
+
+Since it is a common pattern to create a :class:`TestCase` subclass with many
+similarly named test functions, :mod:`unittest` provides a :class:`TestLoader`
+class that can be used to automate the process of creating a test suite and
+populating it with individual tests. For example, ::
+
+ suite = unittest.TestLoader().loadTestsFromTestCase(WidgetTestCase)
+
+will create a test suite that will run ``WidgetTestCase.testDefaultSize()`` and
+``WidgetTestCase.testResize``. :class:`TestLoader` uses the ``'test'`` method
+name prefix to identify test methods automatically.
+
+Note that the order in which the various test cases will be run is determined by
+sorting the test function names with the built-in :func:`cmp` function.
+
+Often it is desirable to group suites of test cases together, so as to run tests
+for the whole system at once. This is easy, since :class:`TestSuite` instances
+can be added to a :class:`TestSuite` just as :class:`TestCase` instances can be
+added to a :class:`TestSuite`::
+
+ suite1 = module1.TheTestSuite()
+ suite2 = module2.TheTestSuite()
+ alltests = unittest.TestSuite([suite1, suite2])
+
+You can place the definitions of test cases and test suites in the same modules
+as the code they are to test (such as :file:`widget.py`), but there are several
+advantages to placing the test code in a separate module, such as
+:file:`test_widget.py`:
+
+* The test module can be run standalone from the command line.
+
+* The test code can more easily be separated from shipped code.
+
+* There is less temptation to change test code to fit the code it tests without
+ a good reason.
+
+* Test code should be modified much less frequently than the code it tests.
+
+* Tested code can be refactored more easily.
+
+* Tests for modules written in C must be in separate modules anyway, so why not
+ be consistent?
+
+* If the testing strategy changes, there is no need to change the source code.
+
+
+.. _legacy-unit-tests:
+
+Re-using old test code
+----------------------
+
+Some users will find that they have existing test code that they would like to
+run from :mod:`unittest`, without converting every old test function to a
+:class:`TestCase` subclass.
+
+For this reason, :mod:`unittest` provides a :class:`FunctionTestCase` class.
+This subclass of :class:`TestCase` can be used to wrap an existing test
+function. Set-up and tear-down functions can also be provided.
+
+Given the following test function::
+
+ def testSomething():
+ something = makeSomething()
+ assert something.name is not None
+ # ...
+
+one can create an equivalent test case instance as follows::
+
+ testcase = unittest.FunctionTestCase(testSomething)
+
+If there are additional set-up and tear-down methods that should be called as
+part of the test case's operation, they can also be provided like so::
+
+ testcase = unittest.FunctionTestCase(testSomething,
+ setUp=makeSomethingDB,
+ tearDown=deleteSomethingDB)
+
+To make migrating existing test suites easier, :mod:`unittest` supports tests
+raising :exc:`AssertionError` to indicate test failure. However, it is
+recommended that you use the explicit :meth:`TestCase.fail\*` and
+:meth:`TestCase.assert\*` methods instead, as future versions of :mod:`unittest`
+may treat :exc:`AssertionError` differently.
+
+.. note::
+
+ Even though :class:`FunctionTestCase` can be used to quickly convert an existing
+ test base over to a :mod:`unittest`\ -based system, this approach is not
+ recommended. Taking the time to set up proper :class:`TestCase` subclasses will
+ make future test refactorings infinitely easier.
+
+
+.. _unittest-contents:
+
+Classes and functions
+---------------------
+
+
+.. class:: TestCase([methodName])
+
+ Instances of the :class:`TestCase` class represent the smallest testable units
+ in the :mod:`unittest` universe. This class is intended to be used as a base
+ class, with specific tests being implemented by concrete subclasses. This class
+ implements the interface needed by the test runner to allow it to drive the
+ test, and methods that the test code can use to check for and report various
+ kinds of failure.
+
+ Each instance of :class:`TestCase` will run a single test method: the method
+ named *methodName*. If you remember, we had an earlier example that went
+ something like this::
+
+ def suite():
+ suite = unittest.TestSuite()
+ suite.addTest(WidgetTestCase('testDefaultSize'))
+ suite.addTest(WidgetTestCase('testResize'))
+ return suite
+
+ Here, we create two instances of :class:`WidgetTestCase`, each of which runs a
+ single test.
+
+ *methodName* defaults to ``'runTest'``.
+
+
+.. class:: FunctionTestCase(testFunc[, setUp[, tearDown[, description]]])
+
+ This class implements the portion of the :class:`TestCase` interface which
+ allows the test runner to drive the test, but does not provide the methods which
+ test code can use to check and report errors. This is used to create test cases
+ using legacy test code, allowing it to be integrated into a :mod:`unittest`\
+ -based test framework.
+
+
+.. class:: TestSuite([tests])
+
+ This class represents an aggregation of individual tests cases and test suites.
+ The class presents the interface needed by the test runner to allow it to be run
+ as any other test case. Running a :class:`TestSuite` instance is the same as
+ iterating over the suite, running each test individually.
+
+ If *tests* is given, it must be an iterable of individual test cases or other
+ test suites that will be used to build the suite initially. Additional methods
+ are provided to add test cases and suites to the collection later on.
+
+
+.. class:: TestLoader()
+
+ This class is responsible for loading tests according to various criteria and
+ returning them wrapped in a :class:`TestSuite`. It can load all tests within a
+ given module or :class:`TestCase` subclass.
+
+
+.. class:: TestResult()
+
+ This class is used to compile information about which tests have succeeded and
+ which have failed.
+
+
+.. data:: defaultTestLoader
+
+ Instance of the :class:`TestLoader` class intended to be shared. If no
+ customization of the :class:`TestLoader` is needed, this instance can be used
+ instead of repeatedly creating new instances.
+
+
+.. class:: TextTestRunner([stream[, descriptions[, verbosity]]])
+
+ A basic test runner implementation which prints results on standard error. It
+ has a few configurable parameters, but is essentially very simple. Graphical
+ applications which run test suites should provide alternate implementations.
+
+
+.. function:: main([module[, defaultTest[, argv[, testRunner[, testLoader]]]]])
+
+ A command-line program that runs a set of tests; this is primarily for making
+ test modules conveniently executable. The simplest use for this function is to
+ include the following line at the end of a test script::
+
+ if __name__ == '__main__':
+ unittest.main()
+
+ The *testRunner* argument can either be a test runner class or an already
+ created instance of it.
+
+In some cases, the existing tests may have been written using the :mod:`doctest`
+module. If so, that module provides a :class:`DocTestSuite` class that can
+automatically build :class:`unittest.TestSuite` instances from the existing
+:mod:`doctest`\ -based tests.
+
+.. versionadded:: 2.3
+
+
+.. _testcase-objects:
+
+TestCase Objects
+----------------
+
+Each :class:`TestCase` instance represents a single test, but each concrete
+subclass may be used to define multiple tests --- the concrete class represents
+a single test fixture. The fixture is created and cleaned up for each test
+case.
+
+:class:`TestCase` instances provide three groups of methods: one group used to
+run the test, another used by the test implementation to check conditions and
+report failures, and some inquiry methods allowing information about the test
+itself to be gathered.
+
+Methods in the first group (running the test) are:
+
+
+.. method:: TestCase.setUp()
+
+ Method called to prepare the test fixture. This is called immediately before
+ calling the test method; any exception raised by this method will be considered
+ an error rather than a test failure. The default implementation does nothing.
+
+
+.. method:: TestCase.tearDown()
+
+ Method called immediately after the test method has been called and the result
+ recorded. This is called even if the test method raised an exception, so the
+ implementation in subclasses may need to be particularly careful about checking
+ internal state. Any exception raised by this method will be considered an error
+ rather than a test failure. This method will only be called if the
+ :meth:`setUp` succeeds, regardless of the outcome of the test method. The
+ default implementation does nothing.
+
+
+.. method:: TestCase.run([result])
+
+ Run the test, collecting the result into the test result object passed as
+ *result*. If *result* is omitted or :const:`None`, a temporary result object is
+ created (by calling the :meth:`defaultTestCase` method) and used; this result
+ object is not returned to :meth:`run`'s caller.
+
+ The same effect may be had by simply calling the :class:`TestCase` instance.
+
+
+.. method:: TestCase.debug()
+
+ Run the test without collecting the result. This allows exceptions raised by
+ the test to be propagated to the caller, and can be used to support running
+ tests under a debugger.
+
+The test code can use any of the following methods to check for and report
+failures.
+
+
+.. method:: TestCase.assert_(expr[, msg])
+ TestCase.failUnless(expr[, msg])
+ TestCase.assertTrue(expr[, msg])
+
+ Signal a test failure if *expr* is false; the explanation for the error will be
+ *msg* if given, otherwise it will be :const:`None`.
+
+
+.. method:: TestCase.assertEqual(first, second[, msg])
+ TestCase.failUnlessEqual(first, second[, msg])
+
+ Test that *first* and *second* are equal. If the values do not compare equal,
+ the test will fail with the explanation given by *msg*, or :const:`None`. Note
+ that using :meth:`failUnlessEqual` improves upon doing the comparison as the
+ first parameter to :meth:`failUnless`: the default value for *msg* can be
+ computed to include representations of both *first* and *second*.
+
+
+.. method:: TestCase.assertNotEqual(first, second[, msg])
+ TestCase.failIfEqual(first, second[, msg])
+
+ Test that *first* and *second* are not equal. If the values do compare equal,
+ the test will fail with the explanation given by *msg*, or :const:`None`. Note
+ that using :meth:`failIfEqual` improves upon doing the comparison as the first
+ parameter to :meth:`failUnless` is that the default value for *msg* can be
+ computed to include representations of both *first* and *second*.
+
+
+.. method:: TestCase.assertAlmostEqual(first, second[, places[, msg]])
+ TestCase.failUnlessAlmostEqual(first, second[, places[, msg]])
+
+ Test that *first* and *second* are approximately equal by computing the
+ difference, rounding to the given number of decimal *places* (default 7),
+ and comparing to zero.
+ Note that comparing a given number of decimal places is not the same as
+ comparing a given number of significant digits. If the values do not compare
+ equal, the test will fail with the explanation given by *msg*, or :const:`None`.
+
+
+.. method:: TestCase.assertNotAlmostEqual(first, second[, places[, msg]])
+ TestCase.failIfAlmostEqual(first, second[, places[, msg]])
+
+ Test that *first* and *second* are not approximately equal by computing the
+ difference, rounding to the given number of decimal *places* (default 7),
+ and comparing to zero.
+ Note that comparing a given number of decimal places is not the same as
+ comparing a given number of significant digits. If the values do not compare
+ equal, the test will fail with the explanation given by *msg*, or :const:`None`.
+
+
+.. method:: TestCase.assertRaises(exception, callable, ...)
+ TestCase.failUnlessRaises(exception, callable, ...)
+
+ Test that an exception is raised when *callable* is called with any positional
+ or keyword arguments that are also passed to :meth:`assertRaises`. The test
+ passes if *exception* is raised, is an error if another exception is raised, or
+ fails if no exception is raised. To catch any of a group of exceptions, a tuple
+ containing the exception classes may be passed as *exception*.
+
+
+.. method:: TestCase.failIf(expr[, msg])
+ TestCase.assertFalse(expr[, msg])
+
+ The inverse of the :meth:`failUnless` method is the :meth:`failIf` method. This
+ signals a test failure if *expr* is true, with *msg* or :const:`None` for the
+ error message.
+
+
+.. method:: TestCase.fail([msg])
+
+ Signals a test failure unconditionally, with *msg* or :const:`None` for the
+ error message.
+
+
+.. attribute:: TestCase.failureException
+
+ This class attribute gives the exception raised by the :meth:`test` method. If
+ a test framework needs to use a specialized exception, possibly to carry
+ additional information, it must subclass this exception in order to "play fair"
+ with the framework. The initial value of this attribute is
+ :exc:`AssertionError`.
+
+Testing frameworks can use the following methods to collect information on the
+test:
+
+
+.. method:: TestCase.countTestCases()
+
+ Return the number of tests represented by this test object. For
+ :class:`TestCase` instances, this will always be ``1``.
+
+
+.. method:: TestCase.defaultTestResult()
+
+ Return an instance of the test result class that should be used for this test
+ case class (if no other result instance is provided to the :meth:`run` method).
+
+ For :class:`TestCase` instances, this will always be an instance of
+ :class:`TestResult`; subclasses of :class:`TestCase` should override this as
+ necessary.
+
+
+.. method:: TestCase.id()
+
+ Return a string identifying the specific test case. This is usually the full
+ name of the test method, including the module and class name.
+
+
+.. method:: TestCase.shortDescription()
+
+ Returns a one-line description of the test, or :const:`None` if no description
+ has been provided. The default implementation of this method returns the first
+ line of the test method's docstring, if available, or :const:`None`.
+
+
+.. _testsuite-objects:
+
+TestSuite Objects
+-----------------
+
+:class:`TestSuite` objects behave much like :class:`TestCase` objects, except
+they do not actually implement a test. Instead, they are used to aggregate
+tests into groups of tests that should be run together. Some additional methods
+are available to add tests to :class:`TestSuite` instances:
+
+
+.. method:: TestSuite.addTest(test)
+
+ Add a :class:`TestCase` or :class:`TestSuite` to the suite.
+
+
+.. method:: TestSuite.addTests(tests)
+
+ Add all the tests from an iterable of :class:`TestCase` and :class:`TestSuite`
+ instances to this test suite.
+
+ This is equivalent to iterating over *tests*, calling :meth:`addTest` for each
+ element.
+
+:class:`TestSuite` shares the following methods with :class:`TestCase`:
+
+
+.. method:: TestSuite.run(result)
+
+ Run the tests associated with this suite, collecting the result into the test
+ result object passed as *result*. Note that unlike :meth:`TestCase.run`,
+ :meth:`TestSuite.run` requires the result object to be passed in.
+
+
+.. method:: TestSuite.debug()
+
+ Run the tests associated with this suite without collecting the result. This
+ allows exceptions raised by the test to be propagated to the caller and can be
+ used to support running tests under a debugger.
+
+
+.. method:: TestSuite.countTestCases()
+
+ Return the number of tests represented by this test object, including all
+ individual tests and sub-suites.
+
+In the typical usage of a :class:`TestSuite` object, the :meth:`run` method is
+invoked by a :class:`TestRunner` rather than by the end-user test harness.
+
+
+.. _testresult-objects:
+
+TestResult Objects
+------------------
+
+A :class:`TestResult` object stores the results of a set of tests. The
+:class:`TestCase` and :class:`TestSuite` classes ensure that results are
+properly recorded; test authors do not need to worry about recording the outcome
+of tests.
+
+Testing frameworks built on top of :mod:`unittest` may want access to the
+:class:`TestResult` object generated by running a set of tests for reporting
+purposes; a :class:`TestResult` instance is returned by the
+:meth:`TestRunner.run` method for this purpose.
+
+:class:`TestResult` instances have the following attributes that will be of
+interest when inspecting the results of running a set of tests:
+
+
+.. attribute:: TestResult.errors
+
+ A list containing 2-tuples of :class:`TestCase` instances and strings holding
+ formatted tracebacks. Each tuple represents a test which raised an unexpected
+ exception.
+
+ .. versionchanged:: 2.2
+ Contains formatted tracebacks instead of :func:`sys.exc_info` results.
+
+
+.. attribute:: TestResult.failures
+
+ A list containing 2-tuples of :class:`TestCase` instances and strings holding
+ formatted tracebacks. Each tuple represents a test where a failure was
+ explicitly signalled using the :meth:`TestCase.fail\*` or
+ :meth:`TestCase.assert\*` methods.
+
+ .. versionchanged:: 2.2
+ Contains formatted tracebacks instead of :func:`sys.exc_info` results.
+
+
+.. attribute:: TestResult.testsRun
+
+ The total number of tests run so far.
+
+
+.. method:: TestResult.wasSuccessful()
+
+ Returns :const:`True` if all tests run so far have passed, otherwise returns
+ :const:`False`.
+
+
+.. method:: TestResult.stop()
+
+ This method can be called to signal that the set of tests being run should be
+ aborted by setting the :class:`TestResult`'s ``shouldStop`` attribute to
+ :const:`True`. :class:`TestRunner` objects should respect this flag and return
+ without running any additional tests.
+
+ For example, this feature is used by the :class:`TextTestRunner` class to stop
+ the test framework when the user signals an interrupt from the keyboard.
+ Interactive tools which provide :class:`TestRunner` implementations can use this
+ in a similar manner.
+
+The following methods of the :class:`TestResult` class are used to maintain the
+internal data structures, and may be extended in subclasses to support
+additional reporting requirements. This is particularly useful in building
+tools which support interactive reporting while tests are being run.
+
+
+.. method:: TestResult.startTest(test)
+
+ Called when the test case *test* is about to be run.
+
+ The default implementation simply increments the instance's ``testsRun``
+ counter.
+
+
+.. method:: TestResult.stopTest(test)
+
+ Called after the test case *test* has been executed, regardless of the outcome.
+
+ The default implementation does nothing.
+
+
+.. method:: TestResult.addError(test, err)
+
+ Called when the test case *test* raises an unexpected exception *err* is a tuple
+ of the form returned by :func:`sys.exc_info`: ``(type, value, traceback)``.
+
+ The default implementation appends a tuple ``(test, formatted_err)`` to the
+ instance's ``errors`` attribute, where *formatted_err* is a formatted
+ traceback derived from *err*.
+
+
+.. method:: TestResult.addFailure(test, err)
+
+ Called when the test case *test* signals a failure. *err* is a tuple of the form
+ returned by :func:`sys.exc_info`: ``(type, value, traceback)``.
+
+ The default implementation appends a tuple ``(test, formatted_err)`` to the
+ instance's ``failures`` attribute, where *formatted_err* is a formatted
+ traceback derived from *err*.
+
+
+.. method:: TestResult.addSuccess(test)
+
+ Called when the test case *test* succeeds.
+
+ The default implementation does nothing.
+
+
+.. _testloader-objects:
+
+TestLoader Objects
+------------------
+
+The :class:`TestLoader` class is used to create test suites from classes and
+modules. Normally, there is no need to create an instance of this class; the
+:mod:`unittest` module provides an instance that can be shared as
+``unittest.defaultTestLoader``. Using a subclass or instance, however, allows
+customization of some configurable properties.
+
+:class:`TestLoader` objects have the following methods:
+
+
+.. method:: TestLoader.loadTestsFromTestCase(testCaseClass)
+
+ Return a suite of all tests cases contained in the :class:`TestCase`\ -derived
+ :class:`testCaseClass`.
+
+
+.. method:: TestLoader.loadTestsFromModule(module)
+
+ Return a suite of all tests cases contained in the given module. This method
+ searches *module* for classes derived from :class:`TestCase` and creates an
+ instance of the class for each test method defined for the class.
+
+ .. warning::
+
+ While using a hierarchy of :class:`TestCase`\ -derived classes can be convenient
+ in sharing fixtures and helper functions, defining test methods on base classes
+ that are not intended to be instantiated directly does not play well with this
+ method. Doing so, however, can be useful when the fixtures are different and
+ defined in subclasses.
+
+
+.. method:: TestLoader.loadTestsFromName(name[, module])
+
+ Return a suite of all tests cases given a string specifier.
+
+ The specifier *name* is a "dotted name" that may resolve either to a module, a
+ test case class, a test method within a test case class, a :class:`TestSuite`
+ instance, or a callable object which returns a :class:`TestCase` or
+ :class:`TestSuite` instance. These checks are applied in the order listed here;
+ that is, a method on a possible test case class will be picked up as "a test
+ method within a test case class", rather than "a callable object".
+
+ For example, if you have a module :mod:`SampleTests` containing a
+ :class:`TestCase`\ -derived class :class:`SampleTestCase` with three test
+ methods (:meth:`test_one`, :meth:`test_two`, and :meth:`test_three`), the
+ specifier ``'SampleTests.SampleTestCase'`` would cause this method to return a
+ suite which will run all three test methods. Using the specifier
+ ``'SampleTests.SampleTestCase.test_two'`` would cause it to return a test suite
+ which will run only the :meth:`test_two` test method. The specifier can refer
+ to modules and packages which have not been imported; they will be imported as a
+ side-effect.
+
+ The method optionally resolves *name* relative to the given *module*.
+
+
+.. method:: TestLoader.loadTestsFromNames(names[, module])
+
+ Similar to :meth:`loadTestsFromName`, but takes a sequence of names rather than
+ a single name. The return value is a test suite which supports all the tests
+ defined for each name.
+
+
+.. method:: TestLoader.getTestCaseNames(testCaseClass)
+
+ Return a sorted sequence of method names found within *testCaseClass*; this
+ should be a subclass of :class:`TestCase`.
+
+The following attributes of a :class:`TestLoader` can be configured either by
+subclassing or assignment on an instance:
+
+
+.. attribute:: TestLoader.testMethodPrefix
+
+ String giving the prefix of method names which will be interpreted as test
+ methods. The default value is ``'test'``.
+
+ This affects :meth:`getTestCaseNames` and all the :meth:`loadTestsFrom\*`
+ methods.
+
+
+.. attribute:: TestLoader.sortTestMethodsUsing
+
+ Function to be used to compare method names when sorting them in
+ :meth:`getTestCaseNames` and all the :meth:`loadTestsFrom\*` methods. The
+ default value is the built-in :func:`cmp` function; the attribute can also be
+ set to :const:`None` to disable the sort.
+
+
+.. attribute:: TestLoader.suiteClass
+
+ Callable object that constructs a test suite from a list of tests. No methods on
+ the resulting object are needed. The default value is the :class:`TestSuite`
+ class.
+
+ This affects all the :meth:`loadTestsFrom\*` methods.
+