Issue 10470: 'python -m unittest' launches test discovery by default.(If you...

Issue 10470:  'python -m unittest' launches test discovery by default.(If you need to pass options to test discovery the discover subcommand must still be specified explicitly.)

Doc/library/unittest.rst

@@ -208,6 +208,10 @@ You can run tests with more detail (higher verbosity) by passing in the -v flag:
 
    python -m unittest -v test_module
 
+When executed without arguments :ref:`unittest-test-discovery` is started::
+
+   python -m unittest
+
 For a list of all the command-line options::
 
    python -m unittest -h
@@ -266,6 +270,12 @@ used from the command line. The basic command-line usage is::
    cd project_directory
    python -m unittest discover
 
+.. note::
+
+   As a shortcut, ``python -m unittest`` is the equivalent of
+   ``python -m unittest discover``. If you want to pass arguments to test
+   discovery the `discover` sub-command must be used explicitly.
+
 The ``discover`` sub-command has the following options:
 
 .. program:: unittest discover

Lib/unittest/main.py

@@ -109,7 +109,8 @@ class TestProgram(object):
         sys.exit(2)
 
     def parseArgs(self, argv):
-        if len(argv) > 1 and argv[1].lower() == 'discover':
+        if ((len(argv) > 1 and argv[1].lower() == 'discover') or
+            (len(argv) == 1 and self.module is None)):
             self._do_discovery(argv[2:])
             return
 

Lib/unittest/test/test_discovery.py

@@ -5,6 +5,18 @@ import sys
 import unittest
 
 
+class TestableTestProgram(unittest.TestProgram):
+    module = '__main__'
+    exit = True
+    defaultTest = failfast = catchbreak = buffer = None
+    verbosity = 1
+    progName = ''
+    testRunner = testLoader = None
+
+    def __init__(self):
+        pass
+
+
 class TestDiscovery(unittest.TestCase):
 
     # Heavily mocked tests so I can avoid hitting the filesystem
@@ -195,8 +207,7 @@ class TestDiscovery(unittest.TestCase):
             test.test_this_does_not_exist()
 
     def test_command_line_handling_parseArgs(self):
-        # Haha - take that uninstantiable class
-        program = object.__new__(unittest.TestProgram)
+        program = TestableTestProgram()
 
         args = []
         def do_discovery(argv):
@@ -208,13 +219,27 @@ class TestDiscovery(unittest.TestCase):
         program.parseArgs(['something', 'discover', 'foo', 'bar'])
         self.assertEqual(args, ['foo', 'bar'])
 
+    def test_command_line_handling_discover_by_default(self):
+        program = TestableTestProgram()
+        program.module = None
+
+        args = []
+        def do_discovery(argv):
+            args.extend(argv)
+        program._do_discovery = do_discovery
+        program.parseArgs(['something'])
+        self.assertEqual(args, [])
+
+        program.parseArgs(['something'])
+        self.assertEqual(args, [])
+
     def test_command_line_handling_do_discovery_too_many_arguments(self):
         class Stop(Exception):
             pass
         def usageExit():
             raise Stop
 
-        program = object.__new__(unittest.TestProgram)
+        program = TestableTestProgram()
         program.usageExit = usageExit
 
         with self.assertRaises(Stop):
@@ -223,7 +248,7 @@ class TestDiscovery(unittest.TestCase):
 
 
     def test_command_line_handling_do_discovery_calls_loader(self):
-        program = object.__new__(unittest.TestProgram)
+        program = TestableTestProgram()
 
         class Loader(object):
             args = []
@@ -237,49 +262,49 @@ class TestDiscovery(unittest.TestCase):
         self.assertEqual(Loader.args, [('.', 'test*.py', None)])
 
         Loader.args = []
-        program = object.__new__(unittest.TestProgram)
+        program = TestableTestProgram()
         program._do_discovery(['--verbose'], Loader=Loader)
         self.assertEqual(program.test, 'tests')
         self.assertEqual(Loader.args, [('.', 'test*.py', None)])
 
         Loader.args = []
-        program = object.__new__(unittest.TestProgram)
+        program = TestableTestProgram()
         program._do_discovery([], Loader=Loader)
         self.assertEqual(program.test, 'tests')
         self.assertEqual(Loader.args, [('.', 'test*.py', None)])
 
         Loader.args = []
-        program = object.__new__(unittest.TestProgram)
+        program = TestableTestProgram()
         program._do_discovery(['fish'], Loader=Loader)
         self.assertEqual(program.test, 'tests')
         self.assertEqual(Loader.args, [('fish', 'test*.py', None)])
 
         Loader.args = []
-        program = object.__new__(unittest.TestProgram)
+        program = TestableTestProgram()
         program._do_discovery(['fish', 'eggs'], Loader=Loader)
         self.assertEqual(program.test, 'tests')
         self.assertEqual(Loader.args, [('fish', 'eggs', None)])
 
         Loader.args = []
-        program = object.__new__(unittest.TestProgram)
+        program = TestableTestProgram()
         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__(unittest.TestProgram)
+        program = TestableTestProgram()
         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__(unittest.TestProgram)
+        program = TestableTestProgram()
         program._do_discovery(['-t', 'fish'], Loader=Loader)
         self.assertEqual(program.test, 'tests')
         self.assertEqual(Loader.args, [('.', 'test*.py', 'fish')])
 
         Loader.args = []
-        program = object.__new__(unittest.TestProgram)
+        program = TestableTestProgram()
         program._do_discovery(['-p', 'fish'], Loader=Loader)
         self.assertEqual(program.test, 'tests')
         self.assertEqual(Loader.args, [('.', 'fish', None)])
@@ -287,7 +312,7 @@ class TestDiscovery(unittest.TestCase):
         self.assertFalse(program.catchbreak)
 
         Loader.args = []
-        program = object.__new__(unittest.TestProgram)
+        program = TestableTestProgram()
         program._do_discovery(['-p', 'eggs', '-s', 'fish', '-v', '-f', '-c'],
                               Loader=Loader)
         self.assertEqual(program.test, 'tests')

Misc/ACKS

@@ -695,6 +695,7 @@ Anthony Roach
 Mark Roberts
 Jim Robinson
 Andy Robinson
+Mark Roddy
 Kevin Rodgers
 Giampaolo Rodola
 Mike Romberg

Misc/NEWS

@@ -32,6 +32,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #10470: 'python -m unittest' will now run test discovery by default,
+  when no extra arguments have been provided.
+
 - Issue #3709: BaseHTTPRequestHandler will buffer the headers and write to
   output stream only when end_headers is invoked. This is a speedup and an
   internal optimization.  Patch by endian.