Factor out convert_argv().

tests/__main__.py

@@ -1,30 +1,42 @@
-
 import os
 import os.path
-from unittest.main import main
 import sys
+import unittest
 
 
 TEST_ROOT = os.path.dirname(__file__)
 PROJECT_ROOT = os.path.dirname(TEST_ROOT)
 
 
-executable = sys.executable + ' -m unittest'
-if all(arg.startswith('-') for arg in sys.argv[1:]):
-    argv = [executable,
-            'discover',
-            '--start-directory', PROJECT_ROOT,
-            '--top-level-directory', PROJECT_ROOT,
-            ] + sys.argv[1:]
-else:
-    argv = [executable] + sys.argv[1:]
-    for i, arg in enumerate(argv[1:], 1):
-        if arg.startswith('-'):
-            continue
-        mod, _, test = arg.partition(':')
-        mod = mod.rstrip(os.sep)
-        mod = mod.rstrip('.py')
-        mod = mod.replace(os.sep, '.')
-        argv[i] = mod if not test else mod + '.' + test
+def convert_argv(argv):
+    args = []
+    modules = set()
+    for arg in argv:
+        # Unittest's main has only flags and positional args.
+        # So we don't worry about options with values.
+        if not arg.startswith('-'):
+            # It must be the name of a test, case, module, or file.
+            # We convert filenames to module names.  For filenames
+            # we support specifying a test name by appending it to
+            # the filename with a ":" in between.
+            mod, _, test = arg.partition(':')
+            if mod.endswith(os.sep):
+                mod = mod.rsplit(os.sep, 1)[0]
+            mod = mod.rsplit('.py', 1)[0]
+            mod = mod.replace(os.sep, '.')
+            arg = mod if not test else mod + '.' + test
+            modules.add(mod)
+        args.append(arg)
+
+    if not modules:
+        # Do discovery.
+        args = ['discover',
+                '--start-directory', PROJECT_ROOT,
+                ] + args
+    return [sys.executable + ' -m unittest'] + args
+    #return [sys.executable, '-m', 'unittest'] + args
+
 
-main(module=None, argv=argv)
+if __name__ == '__main__':
+    argv = convert_argv(sys.argv[1:])
+    unittest.main(module=None, argv=argv)

tests/test_test_main.py

@@ -0,0 +1,46 @@
+import os
+import os.path
+import unittest
+import sys
+
+from .__main__ import convert_argv
+
+
+PROJECT_ROOT = os.path.dirname(os.path.dirname(__file__))
+
+
+class ConvertArgsTests(unittest.TestCase):
+
+    def test_discovery(self):
+        argv = convert_argv(['-v', '--failfast'])
+
+        self.assertEqual(argv, [
+            sys.executable + ' -m unittest',
+            'discover',
+            '--start-directory', PROJECT_ROOT,
+            '-v', '--failfast',
+            ])
+
+    def test_modules(self):
+        argv = convert_argv(['-v', '--failfast',
+                             'w',
+                             'x/y.py:Spam.test_spam'.replace('/', os.sep),
+                             'z:Eggs',
+                             ])
+
+        self.assertEqual(argv, [
+            sys.executable + ' -m unittest',
+            '-v', '--failfast',
+            'w',
+            'x.y.Spam.test_spam',
+            'z.Eggs',
+            ])
+
+    def test_no_args(self):
+        argv = convert_argv([])
+
+        self.assertEqual(argv, [
+            sys.executable + ' -m unittest',
+            'discover',
+            '--start-directory', PROJECT_ROOT,
+            ])