##
5.3.7 TestResult Objects

A `TestResult` object stores the results of a set of tests. The `TestCase` and `TestSuite` classes ensure that results are properly stored; test authors do not need to worry about recording the outcome of tests.

Testing frameworks built on top of `unittest` may want access to the `TestResult` object generated by running a set of tests for reporting purposes; a `TestResult` instance is returned by the `TestRunner.run()` method for this purpose.

Each instance holds the total number of tests run, and collections of failures and errors that occurred among those test runs. The collections contain tuples of `(testcase, traceback)`, where traceback is a string containing a formatted version of the traceback for the exception.

`TestResult` instances have the following attributes that will be of interest when inspecting the results of running a set of tests:

`errors`
  A list containing pairs of `TestCase` instances and the formatted tracebacks for tests which raised an exception but did not signal a test failure. Changed in version 2.2: Contains formatted tracebacks instead of `sys.exc_info()` results.

`failures`
  A list containing pairs of `TestCase` instances and the formatted tracebacks for tests which signalled a failure in the code under test. Changed in version 2.2: Contains formatted tracebacks instead of `sys.exc_info()` results.

`testsRun`
  The number of tests which have been started.

`wasSuccessful`( | )

  Returns true if all tests run so far have passed, otherwise returns false.

The following methods of the `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.

`startTest`( | test)

  Called when the test case test is about to be run.

`stopTest`( | test)

  Called when the test case test has been executed, regardless of the outcome.

`addError`( | test, err)

  Called when the test case test raises an exception without signalling a test failure. err is a tuple of the form returned by `sys.exc_info()`: `(type, value, traceback)`.

`addFailure`( | test, err)

  Called when the test case test signals a failure. err is a tuple of the form returned by `sys.exc_info()`: `(type, value, traceback)`.

`addSuccess`( | test)

  This method is called for a test that does not fail; test is the test case object.

One additional method is available for `TestResult` objects:

`stop`( | )

  This method can be called to signal that the set of tests being run should be aborted. Once this has been called, the `TestRunner` object return to its caller without running any additional tests. This is used by the `TextTestRunner` class to stop the test framework when the user signals an interrupt from the keyboard. Interactive tools which provide runners can use this in a similar manner.