Add test discovery to unittest. Issue 6001.

4 files changed, 630 insertions, 22 deletions

diff --git a/Doc/library/unittest.rst b/Doc/library/unittest.rst
index 39fbb79..bc26f05 100644
--- a/Doc/library/unittest.rst
+++ b/Doc/library/unittest.rst
@@ -90,6 +90,9 @@ need to derive from a specific class.
    `python-mock <http://python-mock.sourceforge.net/>`_ and `minimock <http://blog.ianbicking.org/minimock.html>`_
       Tools for creating mock test objects (objects simulating external resources).
 
+
+.. _unittest-command-line-interface:
+
 Command Line Interface
 ----------------------
 
@@ -100,8 +103,8 @@ modules, classes or even individual test methods::
    python -m unittest test_module.TestClass
    python -m unittest test_module.TestClass.test_method
 
-You can pass in a list with any combination of module names, and fully qualified class or
-method names.
+You can pass in a list with any combination of module names, and fully
+qualified class or method names.
 
 You can run tests with more detail (higher verbosity) by passing in the -v flag::
 
@@ -111,9 +114,47 @@ For a list of all the command line options::
 
    python -m unittest -h
 
-..  versionchanged:: 27
-   In earlier versions it was only possible to run individual test methods and not modules
-   or classes.
+..  versionchanged:: 2.7
+   In earlier versions it was only possible to run individual test methods and
+   not modules or classes.
+
+The command line can also be used for test discovery, for running all of the
+tests in a project or just a subset.
+
+
+.. _unittest-test-discovery:
+
+Test Discovery
+--------------
+
+.. versionadded:: 2.7
+
+unittest supports simple test discovery. For a project's tests to be
+compatible with test discovery they must all be importable from the top level
+directory of the project; i.e. they must all be in Python packages.
+
+Test discovery is implemented in :meth:`TestLoader.discover`, but can also be
+used from the command line. The basic command line usage is::
+
+   cd project_directory
+   python -m unittest discover
+
+The ``discover`` sub-command has the following options:
+
+   -v, --verbose    Verbose output
+   -s directory     Directory to start discovery ('.' default)
+   -p pattern       Pattern to match test files ('test*.py' default)
+   -t directory     Top level directory of project (default to
+                    start directory)
+
+The -s, -p, & -t options can be passsed in as positional arguments. The
+following two command lines are equivalent::
+
+   python -m unittest -s project_directory -p '*_test.py'
+   python -m unittest project_directory '*_test.py'
+
+Test modules and packages can customize test loading and discovery by through
+the `load_tests protocol`_.
 
 .. _unittest-minimal-example:
 
@@ -1151,6 +1192,13 @@ Loading and running tests
          directly does not play well with this method.  Doing so, however, can
          be useful when the fixtures are different and defined in subclasses.
 
+      If a module provides a ``load_tests`` function it will be called to
+      load the tests. This allows modules to customize test loading.
+      This is the `load_tests protocol`_.
+
+      .. versionchanged:: 2.7
+         Support for ``load_tests`` added.
+
 
    .. method:: loadTestsFromName(name[, module])
 
@@ -1165,13 +1213,14 @@ Loading and running tests
       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
+      :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*.
@@ -1189,6 +1238,31 @@ Loading and running tests
       Return a sorted sequence of method names found within *testCaseClass*;
       this should be a subclass of :class:`TestCase`.
 
+
+   .. method:: discover(start_dir, pattern='test*.py', top_level_dir=None)
+
+      Find and return all test modules from the specified start directory,
+      recursing into subdirectories to find them. Only test files that match
+      *pattern* will be loaded. (Using shell style pattern matching.)
+
+      All test modules must be importable from the top level of the project. If
+      the start directory is not the top level directory then the top level
+      directory must be specified separately.
+
+      If a test package name (directory with :file:`__init__.py`) matches the
+      pattern then the package will be checked for a ``load_tests``
+      function. If this exists then it will be called with *loader*, *tests*,
+      *pattern*.
+
+      If load_tests exists then discovery does  *not* recurse into the package,
+      ``load_tests`` is responsible for loading all tests in the package.
+
+      The pattern is deliberately not stored as a loader attribute so that
+      packages can continue discovery themselves. *top_level_dir* is stored so
+      ``load_tests`` does not need to pass this argument in to
+      ``loader.discover()``.
+
+
    The following attributes of a :class:`TestLoader` can be configured either by
    subclassing or assignment on an instance:
 
@@ -1353,8 +1427,8 @@ Loading and running tests
 
    .. method:: 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)``.
+      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 :attr:`failures` attribute, where *formatted_err* is a
@@ -1447,3 +1521,68 @@ Loading and running tests
 
    .. versionchanged:: 2.7
       The ``exit`` and ``verbosity`` parameters were added.
+
+
+load_tests Protocol
+###################
+
+Modules or packages can customize how tests are loaded from them during normal
+test runs or test discovery by implementing a function called ``load_tests``.
+
+If a test module defines ``load_tests`` it will be called by
+:meth:`TestLoader.loadTestsFromModule` with the following arguments::
+
+    load_tests(loader, standard_tests, None)
+
+It should return a :class:`TestSuite`.
+
+*loader* is the instance of :class:`TestLoader` doing the loading.
+*standard_tests* are the tests that would be loaded by default from the
+module. It is common for test modules to only want to add or remove tests
+from the standard set of tests.
+The third argument is used when loading packages as part of test discovery.
+
+A typical ``load_tests`` function that loads tests from a specific set of
+:class:`TestCase` classes may look like::
+
+    test_cases = (TestCase1, TestCase2, TestCase3)
+
+    def load_tests(loader, tests, pattern):
+        suite = TestSuite()
+        for test_class in test_cases:
+            tests = loader.loadTestsFromTestCase(test_class)
+            suite.addTests(tests)
+        return suite
+
+If discovery is started, either from the command line or by calling
+:meth:`TestLoader.discover`, with a pattern that matches a package
+name then the package :file:`__init__.py` will be checked for ``load_tests``.
+
+.. note::
+
+   The default pattern is 'test*.py'. This matches all python files
+   that start with 'test' but *won't* match any test directories.
+
+   A pattern like 'test*' will match test packages as well as
+   modules.
+
+If the package :file:`__init__.py` defines ``load_tests`` then it will be
+called and discovery not continued into the package. ``load_tests``
+is called with the following arguments::
+
+    load_tests(loader, standard_tests, pattern)
+
+This should return a :class:`TestSuite` representing all the tests
+from the package. (``standard_tests`` will only contain tests
+collected from :file:`__init__.py`.)
+
+Because the pattern is passed into ``load_tests`` the package is free to
+continue (and potentially modify) test discovery. A 'do nothing'
+``load_tests`` function for a test package would look like::
+
+    def load_tests(loader, standard_tests, pattern):
+        # top level directory cached on loader instance
+        this_dir = os.path.dirname(__file__)
+        package_tests = loader.discover(start_dir=this_dir, pattern=pattern)
+        standard_tests.addTests(package_tests)
+        return standard_tests
diff --git a/Lib/test/test_unittest.py b/Lib/test/test_unittest.py
index 9c1fe2a..950b2ca 100644
--- a/Lib/test/test_unittest.py
+++ b/Lib/test/test_unittest.py
@@ -7,7 +7,9 @@ Still need testing:
 """
 
 from StringIO import StringIO
+import os
 import re
+import sys
 from test import test_support
 import unittest
 from unittest import TestCase, TestProgram
@@ -256,6 +258,30 @@ class Test_TestLoader(TestCase):
         reference = [unittest.TestSuite([MyTestCase('test')])]
         self.assertEqual(list(suite), reference)
 
+
+    # Check that loadTestsFromModule honors (or not) a module
+    # with a load_tests function.
+    def test_loadTestsFromModule__load_tests(self):
+        m = types.ModuleType('m')
+        class MyTestCase(unittest.TestCase):
+            def test(self):
+                pass
+        m.testcase_1 = MyTestCase
+
+        load_tests_args = []
+        def load_tests(loader, tests, pattern):
+            load_tests_args.extend((loader, tests, pattern))
+            return tests
+        m.load_tests = load_tests
+
+        loader = unittest.TestLoader()
+        suite = loader.loadTestsFromModule(m)
+        self.assertEquals(load_tests_args, [loader, suite, None])
+
+        load_tests_args = []
+        suite = loader.loadTestsFromModule(m, use_load_tests=False)
+        self.assertEquals(load_tests_args, [])
+
     ################################################################
     ### /Tests for TestLoader.loadTestsFromModule()
 
@@ -3379,6 +3405,275 @@ class Test_TextTestRunner(TestCase):
         self.assertEqual(events, expected)
 
 
+class TestDiscovery(TestCase):
+
+    # Heavily mocked tests so I can avoid hitting the filesystem
+    def test_get_module_from_path(self):
+        loader = unittest.TestLoader()
+
+        def restore_import():
+            unittest.__import__ = __import__
+        unittest.__import__ = lambda *_: None
+        self.addCleanup(restore_import)
+
+        expected_module = object()
+        def del_module():
+            del sys.modules['bar.baz']
+        sys.modules['bar.baz'] = expected_module
+        self.addCleanup(del_module)
+
+        loader._top_level_dir = '/foo'
+        module = loader._get_module_from_path('/foo/bar/baz.py')
+        self.assertEqual(module, expected_module)
+
+        if not __debug__:
+            # asserts are off
+            return
+
+        with self.assertRaises(AssertionError):
+            loader._get_module_from_path('/bar/baz.py')
+
+    def test_find_tests(self):
+        loader = unittest.TestLoader()
+
+        original_listdir = os.listdir
+        def restore_listdir():
+            os.listdir = original_listdir
+        original_isfile = os.path.isfile
+        def restore_isfile():
+            os.path.isfile = original_isfile
+        original_isdir = os.path.isdir
+        def restore_isdir():
+            os.path.isdir = original_isdir
+
+        path_lists = [['test1.py', 'test2.py', 'not_a_test.py', 'test_dir',
+                       'test.foo', 'another_dir'],
+                      ['test3.py', 'test4.py', ]]
+        os.listdir = lambda path: path_lists.pop(0)
+        self.addCleanup(restore_listdir)
+
+        def isdir(path):
+            return path.endswith('dir')
+        os.path.isdir = isdir
+        self.addCleanup(restore_isdir)
+
+        def isfile(path):
+            # another_dir is not a package and so shouldn't be recursed into
+            return not path.endswith('dir') and not 'another_dir' in path
+        os.path.isfile = isfile
+        self.addCleanup(restore_isfile)
+
+        loader._get_module_from_path = lambda path: path + ' module'
+        loader.loadTestsFromModule = lambda module: module + ' tests'
+
+        loader._top_level_dir = '/foo'
+        suite = list(loader._find_tests('/foo', 'test*.py'))
+
+        expected = [os.path.join('/foo', name) + ' module tests' for name in
+                    ('test1.py', 'test2.py')]
+        expected.extend([os.path.join('/foo', 'test_dir', name) + ' module tests' for name in
+                    ('test3.py', 'test4.py')])
+        self.assertEqual(suite, expected)
+
+    def test_find_tests_with_package(self):
+        loader = unittest.TestLoader()
+
+        original_listdir = os.listdir
+        def restore_listdir():
+            os.listdir = original_listdir
+        original_isfile = os.path.isfile
+        def restore_isfile():
+            os.path.isfile = original_isfile
+        original_isdir = os.path.isdir
+        def restore_isdir():
+            os.path.isdir = original_isdir
+
+        directories = ['a_directory', 'test_directory', 'test_directory2']
+        path_lists = [directories, [], [], []]
+        os.listdir = lambda path: path_lists.pop(0)
+        self.addCleanup(restore_listdir)
+
+        os.path.isdir = lambda path: True
+        self.addCleanup(restore_isdir)
+
+        os.path.isfile = lambda path: os.path.basename(path) not in directories
+        self.addCleanup(restore_isfile)
+
+        class Module(object):
+            paths = []
+            load_tests_args = []
+
+            def __init__(self, path):
+                self.path = path
+                self.paths.append(path)
+                if os.path.basename(path) == 'test_directory':
+                    def load_tests(loader, tests, pattern):
+                        self.load_tests_args.append((loader, tests, pattern))
+                        return 'load_tests'
+                    self.load_tests = load_tests
+
+            def __eq__(self, other):
+                return self.path == other.path
+
+        loader._get_module_from_path = lambda path: Module(path)
+        def loadTestsFromModule(module, use_load_tests):
+            if use_load_tests:
+                raise self.failureException('use_load_tests should be False for packages')
+            return module.path + ' module tests'
+        loader.loadTestsFromModule = loadTestsFromModule
+
+        loader._top_level_dir = '/foo'
+        # this time no '.py' on the pattern so that it can match
+        # a test package
+        suite = list(loader._find_tests('/foo', 'test*'))
+
+        # We should have loaded tests from the test_directory package by calling load_tests
+        # and directly from the test_directory2 package
+        self.assertEqual(suite, ['load_tests', '/foo/test_directory2 module tests'])
+        self.assertEqual(Module.paths, [os.path.join('/foo', 'test_directory'),
+                                        os.path.join('/foo', 'test_directory2')])
+
+        # load_tests should have been called once with loader, tests and pattern
+        self.assertEqual(Module.load_tests_args,
+                         [(loader, os.path.join('/foo', 'test_directory') + ' module tests',
+                           'test*')])
+
+    def test_discover(self):
+        loader = unittest.TestLoader()
+
+        original_isfile = os.path.isfile
+        def restore_isfile():
+            os.path.isfile = original_isfile
+
+        os.path.isfile = lambda path: False
+        self.addCleanup(restore_isfile)
+
+        full_path = os.path.abspath(os.path.normpath('/foo'))
+        def clean_path():
+            if sys.path[-1] == full_path:
+                sys.path.pop(-1)
+        self.addCleanup(clean_path)
+
+        with self.assertRaises(ImportError):
+            loader.discover('/foo/bar', top_level_dir='/foo')
+
+        self.assertEqual(loader._top_level_dir, full_path)
+        self.assertIn(full_path, sys.path)
+
+        os.path.isfile = lambda path: True
+        _find_tests_args = []
+        def _find_tests(start_dir, pattern):
+            _find_tests_args.append((start_dir, pattern))
+            return ['tests']
+        loader._find_tests = _find_tests
+        loader.suiteClass = str
+
+        suite = loader.discover('/foo/bar/baz', 'pattern', '/foo/bar')
+
+        top_level_dir = os.path.abspath(os.path.normpath('/foo/bar'))
+        start_dir = os.path.abspath(os.path.normpath('/foo/bar/baz'))
+        self.assertEqual(suite, "['tests']")
+        self.assertEqual(loader._top_level_dir, top_level_dir)
+        self.assertEqual(_find_tests_args, [(start_dir, 'pattern')])
+
+    def test_command_line_handling_parseArgs(self):
+        # Haha - take that uninstantiable class
+        program = object.__new__(TestProgram)
+
+        args = []
+        def do_discovery(argv):
+            args.extend(argv)
+        program._do_discovery = do_discovery
+        program.parseArgs(['something', 'discover'])
+        self.assertEqual(args, [])
+
+        program.parseArgs(['something', 'discover', 'foo', 'bar'])
+        self.assertEqual(args, ['foo', 'bar'])
+
+    def test_command_line_handling_do_discovery_too_many_arguments(self):
+        class Stop(Exception):
+            pass
+        def usageExit():
+            raise Stop
+
+        program = object.__new__(TestProgram)
+        program.usageExit = usageExit
+
+        with self.assertRaises(Stop):
+            # too many args
+            program._do_discovery(['one', 'two', 'three', 'four'])
+
+
+    def test_command_line_handling_do_discovery_calls_loader(self):
+        program = object.__new__(TestProgram)
+
+        class Loader(object):
+            args = []
+            def discover(self, start_dir, pattern, top_level_dir):
+                self.args.append((start_dir, pattern, top_level_dir))
+                return 'tests'
+
+        program._do_discovery(['-v'], Loader=Loader)
+        self.assertEqual(program.verbosity, 2)
+        self.assertEqual(program.test, 'tests')
+        self.assertEqual(Loader.args, [('.', 'test*.py', None)])
+
+        Loader.args = []
+        program = object.__new__(TestProgram)
+        program._do_discovery(['--verbose'], Loader=Loader)
+        self.assertEqual(program.test, 'tests')
+        self.assertEqual(Loader.args, [('.', 'test*.py', None)])
+
+        Loader.args = []
+        program = object.__new__(TestProgram)
+        program._do_discovery([], Loader=Loader)
+        self.assertEqual(program.test, 'tests')
+        self.assertEqual(Loader.args, [('.', 'test*.py', None)])
+
+        Loader.args = []
+        program = object.__new__(TestProgram)
+        program._do_discovery(['fish'], Loader=Loader)
+        self.assertEqual(program.test, 'tests')
+        self.assertEqual(Loader.args, [('fish', 'test*.py', None)])
+
+        Loader.args = []
+        program = object.__new__(TestProgram)
+        program._do_discovery(['fish', 'eggs'], Loader=Loader)
+        self.assertEqual(program.test, 'tests')
+        self.assertEqual(Loader.args, [('fish', 'eggs', None)])
+
+        Loader.args = []
+        program = object.__new__(TestProgram)
+        program._do_discovery(['fish', 'eggs', 'ham'], Loader=Loader)
+        self.assertEqual(program.test, 'tests')
+        self.assertEqual(Loader.args, [('fish', 'eggs', 'ham')])
+
+        Loader.args = []
+        program = object.__new__(TestProgram)
+        program._do_discovery(['-s', 'fish'], Loader=Loader)
+        self.assertEqual(program.test, 'tests')
+        self.assertEqual(Loader.args, [('fish', 'test*.py', None)])
+
+        Loader.args = []
+        program = object.__new__(TestProgram)
+        program._do_discovery(['-t', 'fish'], Loader=Loader)
+        self.assertEqual(program.test, 'tests')
+        self.assertEqual(Loader.args, [('.', 'test*.py', 'fish')])
+
+        Loader.args = []
+        program = object.__new__(TestProgram)
+        program._do_discovery(['-p', 'fish'], Loader=Loader)
+        self.assertEqual(program.test, 'tests')
+        self.assertEqual(Loader.args, [('.', 'fish', None)])
+
+        Loader.args = []
+        program = object.__new__(TestProgram)
+        program._do_discovery(['-p', 'eggs', '-s', 'fish', '-v'], Loader=Loader)
+        self.assertEqual(program.test, 'tests')
+        self.assertEqual(Loader.args, [('fish', 'eggs', None)])
+        self.assertEqual(program.verbosity, 2)
+
+
 ######################################################################
 ## Main
 ######################################################################
@@ -3387,7 +3682,7 @@ def test_main():
     test_support.run_unittest(Test_TestCase, Test_TestLoader,
         Test_TestSuite, Test_TestResult, Test_FunctionTestCase,
         Test_TestSkipping, Test_Assertions, TestLongMessage,
-        Test_TestProgram, TestCleanUp)
+        Test_TestProgram, TestCleanUp, TestDiscovery)
 
 if __name__ == "__main__":
     test_main()
diff --git a/Lib/unittest.py b/Lib/unittest.py
index ca20f92..c8943e7 100644
--- a/Lib/unittest.py
+++ b/Lib/unittest.py
@@ -56,6 +56,9 @@ import traceback
 import types
 import warnings
 
+from fnmatch import fnmatch
+
+
 ##############################################################################
 # Exported classes and functions
 ##############################################################################
@@ -1196,6 +1199,7 @@ class TestLoader(object):
     testMethodPrefix = 'test'
     sortTestMethodsUsing = cmp
     suiteClass = TestSuite
+    _top_level_dir = None
 
     def loadTestsFromTestCase(self, testCaseClass):
         """Return a suite of all tests cases contained in testCaseClass"""
@@ -1208,13 +1212,17 @@ class TestLoader(object):
         suite = self.suiteClass(map(testCaseClass, testCaseNames))
         return suite
 
-    def loadTestsFromModule(self, module):
+    def loadTestsFromModule(self, module, use_load_tests=True):
         """Return a suite of all tests cases contained in the given module"""
         tests = []
         for name in dir(module):
             obj = getattr(module, name)
             if isinstance(obj, type) and issubclass(obj, TestCase):
                 tests.append(self.loadTestsFromTestCase(obj))
+
+        load_tests = getattr(module, 'load_tests', None)
+        if use_load_tests and load_tests is not None:
+            return load_tests(self, tests, None)
         return self.suiteClass(tests)
 
     def loadTestsFromName(self, name, module=None):
@@ -1283,7 +1291,97 @@ class TestLoader(object):
             testFnNames.sort(key=_CmpToKey(self.sortTestMethodsUsing))
         return testFnNames
 
+    def discover(self, start_dir, pattern='test*.py', top_level_dir=None):
+        """Find and return all test modules from the specified start
+        directory, recursing into subdirectories to find them. Only test files
+        that match the pattern will be loaded. (Using shell style pattern
+        matching.)
+
+        All test modules must be importable from the top level of the project.
+        If the start directory is not the top level directory then the top
+        level directory must be specified separately.
+
+        If a test package name (directory with '__init__.py') matches the
+        pattern then the package will be checked for a 'load_tests' function. If
+        this exists then it will be called with loader, tests, pattern.
+
+        If load_tests exists then discovery does  *not* recurse into the package,
+        load_tests is responsible for loading all tests in the package.
+
+        The pattern is deliberately not stored as a loader attribute so that
+        packages can continue discovery themselves. top_level_dir is stored so
+        load_tests does not need to pass this argument in to loader.discover().
+        """
+        if top_level_dir is None and self._top_level_dir is not None:
+            # make top_level_dir optional if called from load_tests in a package
+            top_level_dir = self._top_level_dir
+        elif top_level_dir is None:
+            top_level_dir = start_dir
+
+        top_level_dir = os.path.abspath(os.path.normpath(top_level_dir))
+        start_dir = os.path.abspath(os.path.normpath(start_dir))
+
+        if not top_level_dir in sys.path:
+            # all test modules must be importable from the top level directory
+            sys.path.append(top_level_dir)
+        self._top_level_dir = top_level_dir
+
+        if start_dir != top_level_dir and not os.path.isfile(os.path.join(start_dir, '__init__.py')):
+            # what about __init__.pyc or pyo (etc)
+            raise ImportError('Start directory is not importable: %r' % start_dir)
 
+        tests = list(self._find_tests(start_dir, pattern))
+        return self.suiteClass(tests)
+
+
+    def _get_module_from_path(self, path):
+        """Load a module from a path relative to the top-level directory
+        of a project. Used by discovery."""
+        path = os.path.splitext(os.path.normpath(path))[0]
+
+        relpath = os.path.relpath(path, self._top_level_dir)
+        assert not os.path.isabs(relpath), "Path must be within the project"
+        assert not relpath.startswith('..'), "Path must be within the project"
+
+        name = relpath.replace(os.path.sep, '.')
+        __import__(name)
+        return sys.modules[name]
+
+    def _find_tests(self, start_dir, pattern):
+        """Used by discovery. Yields test suites it loads."""
+        paths = os.listdir(start_dir)
+
+        for path in paths:
+            full_path = os.path.join(start_dir, path)
+            # what about __init__.pyc or pyo (etc)
+            # we would need to avoid loading the same tests multiple times
+            # from '.py', '.pyc' *and* '.pyo'
+            if os.path.isfile(full_path) and path.lower().endswith('.py'):
+                if fnmatch(path, pattern):
+                    # if the test file matches, load it
+                    module = self._get_module_from_path(full_path)
+                    yield self.loadTestsFromModule(module)
+            elif os.path.isdir(full_path):
+                if not os.path.isfile(os.path.join(full_path, '__init__.py')):
+                    continue
+
+                load_tests = None
+                tests = None
+                if fnmatch(path, pattern):
+                    # only check load_tests if the package directory itself matches the filter
+                    package = self._get_module_from_path(full_path)
+                    load_tests = getattr(package, 'load_tests', None)
+                    tests = self.loadTestsFromModule(package, use_load_tests=False)
+
+                if load_tests is None:
+                    if tests is not None:
+                        # tests loaded from package file
+                        yield tests
+                    # recurse into the package
+                    for test in self._find_tests(full_path, pattern):
+                        yield test
+                else:
+                    yield load_tests(self, tests, pattern)
 
 defaultTestLoader = TestLoader()
 
@@ -1484,11 +1582,37 @@ class TextTestRunner(object):
 # Facilities for running tests from the command line
 ##############################################################################
 
-class TestProgram(object):
-    """A command-line program that runs a set of tests; this is primarily
-       for making test modules conveniently executable.
-    """
-    USAGE = """\
+USAGE_AS_MAIN = """\
+Usage: %(progName)s [options] [tests]
+
+Options:
+  -h, --help       Show this message
+  -v, --verbose    Verbose output
+  -q, --quiet      Minimal output
+
+Examples:
+  %(progName)s test_module                       - run tests from test_module
+  %(progName)s test_module.TestClass             - run tests from
+                                                   test_module.TestClass
+  %(progName)s test_module.TestClass.test_method - run specified test method
+
+[tests] can be a list of any number of test modules, classes and test
+methods.
+
+Alternative Usage: %(progName)s discover [options]
+
+Options:
+  -v, --verbose    Verbose output
+  -s directory     Directory to start discovery ('.' default)
+  -p pattern       Pattern to match test files ('test*.py' default)
+  -t directory     Top level directory of project (default to
+                   start directory)
+
+For test discovery all test modules must be importable from the top
+level directory of the project.
+"""
+
+USAGE_FROM_MODULE = """\
 Usage: %(progName)s [options] [test] [...]
 
 Options:
@@ -1503,6 +1627,18 @@ Examples:
   %(progName)s MyTestCase                    - run all 'test*' test methods
                                                in MyTestCase
 """
+
+if __name__ == '__main__':
+    USAGE = USAGE_AS_MAIN
+else:
+    USAGE = USAGE_FROM_MODULE
+
+
+class TestProgram(object):
+    """A command-line program that runs a set of tests; this is primarily
+       for making test modules conveniently executable.
+    """
+    USAGE = USAGE
     def __init__(self, module='__main__', defaultTest=None,
                  argv=None, testRunner=TextTestRunner,
                  testLoader=defaultTestLoader, exit=True,
@@ -1532,6 +1668,10 @@ Examples:
         sys.exit(2)
 
     def parseArgs(self, argv):
+        if len(argv) > 1 and argv[1].lower() == 'discover':
+            self._do_discovery(argv[2:])
+            return
+
         import getopt
         long_opts = ['help','verbose','quiet']
         try:
@@ -1548,7 +1688,8 @@ Examples:
                 return
             if len(args) > 0:
                 self.testNames = args
-                if sys.modules['unittest'] is sys.modules['__main__']:
+                if __name__ == '__main__':
+                    # to support python -m unittest ...
                     self.module = None
             else:
                 self.testNames = (self.defaultTest,)
@@ -1560,6 +1701,36 @@ Examples:
         self.test = self.testLoader.loadTestsFromNames(self.testNames,
                                                        self.module)
 
+    def _do_discovery(self, argv, Loader=TestLoader):
+        # handle command line args for test discovery
+        import optparse
+        parser = optparse.OptionParser()
+        parser.add_option('-v', '--verbose', dest='verbose', default=False,
+                          help='Verbose output', action='store_true')
+        parser.add_option('-s', '--start-directory', dest='start', default='.',
+                          help="Directory to start discovery ('.' default)")
+        parser.add_option('-p', '--pattern', dest='pattern', default='test*.py',
+                          help="Pattern to match tests ('test*.py' default)")
+        parser.add_option('-t', '--top-level-directory', dest='top', default=None,
+                          help='Top level directory of project (defaults to start directory)')
+
+        options, args = parser.parse_args(argv)
+        if len(args) > 3:
+            self.usageExit()
+
+        for name, value in zip(('start', 'pattern', 'top'), args):
+            setattr(options, name, value)
+
+        if options.verbose:
+            self.verbosity = 2
+
+        start_dir = options.start
+        pattern = options.pattern
+        top_level_dir = options.top
+
+        loader = Loader()
+        self.test = loader.discover(start_dir, pattern, top_level_dir)
+
     def runTests(self):
         if isinstance(self.testRunner, (type, types.ClassType)):
             try:
diff --git a/Misc/NEWS b/Misc/NEWS
index 7e53d24..73ddbe7 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -503,6 +503,9 @@ Library
 
 - unittest.assertNotEqual() now uses the inequality operator (!=) instead
   of the equality operator.
+  
+- Issue #6001: Test discovery for unittest. Implemented in 
+  unittest.TestLoader.discover and from the command line.
 
 - Issue #5679: The methods unittest.TestCase.addCleanup and doCleanups were added.
   addCleanup allows you to add cleanup functions that will be called