Automatically discovering tests
===============================

You can explicitly specify which tests to run by providing a function that
returns a unittest.TestSuite in the test modules (the name of the function can
be configured with the --suite-name parameter, it defaults to 'test_suite'). If
no such function is present, testrunner will use all classes in the module that
inherit from unittest.TestCase as tests:

    >>> import os, sys
    >>> directory_with_tests = os.path.join(this_directory, 'testrunner-ex')

    >>> from zope.testing import testrunner

    >>> defaults = [
    ...     '--path', directory_with_tests,
    ...     '--tests-pattern', '^sampletestsf?$',
    ...     ]
    >>> sys.argv = ['test',
    ...             '--tests-pattern', '^sampletests_discover$',
    ...     ]
    >>> testrunner.run(defaults)
    Running zope.testing.testrunner.layer.UnitTests tests:
      Set up zope.testing.testrunner.layer.UnitTests in N.NNN seconds.
      Ran 1 tests with 0 failures and 0 errors in N.NNN seconds.
    Tearing down left over layers:
      Tear down zope.testing.testrunner.layer.UnitTests in N.NNN seconds.
    False

If the module neither provides a TestSuite nor has discoverable tests,
testrunner will exit with an error to prevent acidentally missing test cases:

    >>> sys.argv = ['test',
    ...             '--tests-pattern', '^sampletests_discover_notests$',
    ...     ]
    >>> testrunner.run(defaults)
    Test-module import failures:
    <BLANKLINE>
    Module: sample1.sampletests_discover_notests
    <BLANKLINE>
    TypeError: Module sample1.sampletests_discover_notests does not define any tests
    <BLANKLINE>
    <BLANKLINE>
    <BLANKLINE>
    Test-modules with import problems:
      sample1.sampletests_discover_notests
    Total: 0 tests, 0 failures, 0 errors in 0.000 seconds.
    True