finish

Author: Wulian233

Lib/mimetypes.py

@@ -717,29 +717,30 @@ def _parse_args(args):
 
 
 def _main(args=None):
-    """Run the mimetypes command-line interface."""
+    """Run the mimetypes command-line interface and return a text to print."""
     import sys
 
     args, help_text = _parse_args(args)
-    if not args.type:
-        print(help_text)
-        return
 
+    results = []
     if args.extension:
         for gtype in args.type:
             guess = guess_extension(gtype, not args.lenient)
             if guess:
-                print(str(guess))
+                results.append(str(guess))
             else:
-                print(f"error: unknown type {gtype}", file=sys.stderr)
+                sys.exit(f"error: unknown type {gtype}")
+        return '\n'.join(results)
     else:
         for gtype in args.type:
             guess, encoding = guess_type(gtype, not args.lenient)
             if guess:
-                print(f"type: {guess} encoding: {encoding}")
+                results.append(f"type: {guess} encoding: {encoding}")
             else:
-                print(f"error: media type unknown for {gtype}", file=sys.stderr)
+                sys.exit(f"error: media type unknown for {gtype}")
+        return '\n'.join(results)
+    return help_text
 
 
 if __name__ == '__main__':
-    _main()
+    print(_main())

Lib/test/test_mimetypes.py

@@ -1,4 +1,3 @@
-import contextlib
 import io
 import mimetypes
 import os
@@ -477,22 +476,16 @@ def test_invocation(self):
             ("-e image/jpeg", ".jpg"),
             ("-l foo.webp", "type: image/webp encoding: None"),
         ]:
-            with self.subTest(command=command):
-                out = io.StringIO()
-                with contextlib.redirect_stdout(out):
-                    mimetypes._main(shlex.split(command))
-                self.assertEqual(out.getvalue().strip(), expected)
+            self.assertEqual(mimetypes._main(shlex.split(command)), expected)
 
     def test_invocation_error(self):
         for command, expected in [
             ("-e image/jpg", "error: unknown type image/jpg"),
             ("foo.bar_ext", "error: media type unknown for foo.bar_ext"),
         ]:
             with self.subTest(command=command):
-                err = io.StringIO()
-                with contextlib.redirect_stderr(err):
+                with self.assertRaisesRegex(SystemExit, expected):
                     mimetypes._main(shlex.split(command))
-                self.assertIn(expected, err.getvalue().strip())
 
 
 if __name__ == "__main__":