CLI: fix entry point not taking into account arguments (#255)

Author: BoboTiG

CHANGELOG.md

@@ -3,8 +3,7 @@
 See Git checking messages for full history.
 
 ## 9.0.1 (2023/xx/xx)
-- 
-- :heart: contributors: @
+- CLI: fixed entry point not taking into account arguments
 
 ## 9.0.0 (2023/04/18)
 - Linux: add failure handling to `XOpenDisplay()` call (fixes #246)

src/mss/__main__.py

@@ -3,6 +3,7 @@
 Source: https://github.com/BoboTiG/python-mss
 """
 import os.path
+import sys
 from argparse import ArgumentParser
 
 from . import __version__
@@ -14,7 +15,7 @@
 def main(*args: str) -> int:
     """Main logic."""
 
-    cli_args = ArgumentParser()
+    cli_args = ArgumentParser(prog="mss")
     cli_args.add_argument(
         "-c",
         "--coordinates",
@@ -42,7 +43,7 @@ def main(*args: str) -> int:
     )
     cli_args.add_argument("-v", "--version", action="version", version=__version__)
 
-    options = cli_args.parse_args(args)
+    options = cli_args.parse_args(args or None)
     kwargs = {"mon": options.monitor, "output": options.output}
     if options.coordinates:
         try:
@@ -80,6 +81,4 @@ def main(*args: str) -> int:
 
 
 if __name__ == "__main__":  # pragma: nocover
-    import sys
-
-    sys.exit(main(*sys.argv[1:]))
+    sys.exit(main())

src/tests/test_implementation.py

@@ -5,12 +5,15 @@
 import os
 import os.path
 import platform
-from unittest.mock import patch
+import sys
+from datetime import datetime
+from unittest.mock import Mock, patch
 
 import pytest
 
 import mss.tools
 from mss import mss
+from mss.__main__ import main as entry_point
 from mss.base import MSSBase
 from mss.exception import ScreenShotError
 from mss.screenshot import ScreenShot
@@ -78,46 +81,43 @@ def test_factory(monkeypatch):
     assert error == "System 'chuck norris' not (yet?) implemented."
 
 
+@patch.object(sys, "argv", new=[])  # Prevent side effects while testing
 @pytest.mark.parametrize("with_cursor", [False, True])
 def test_entry_point(with_cursor: bool, capsys):
-    from datetime import datetime
-
-    from mss.__main__ import main as entry_point
-
     def main(*args: str, ret: int = 0) -> None:
         if with_cursor:
             args = args + ("--with-cursor",)
         assert entry_point(*args) == ret
 
     # No arguments
     main()
-    out, _ = capsys.readouterr()
-    for mon, line in enumerate(out.splitlines(), 1):
+    captured = capsys.readouterr()
+    for mon, line in enumerate(captured.out.splitlines(), 1):
         filename = f"monitor-{mon}.png"
         assert line.endswith(filename)
         assert os.path.isfile(filename)
         os.remove(filename)
 
     for opt in ("-m", "--monitor"):
         main(opt, "1")
-        out, _ = capsys.readouterr()
-        assert out.endswith("monitor-1.png\n")
+        captured = capsys.readouterr()
+        assert captured.out.endswith("monitor-1.png\n")
         assert os.path.isfile("monitor-1.png")
         os.remove("monitor-1.png")
 
     for opt in zip(["-m 1", "--monitor=1"], ["-q", "--quiet"]):
         main(*opt)
-        out, _ = capsys.readouterr()
-        assert not out
+        captured = capsys.readouterr()
+        assert not captured.out
         assert os.path.isfile("monitor-1.png")
         os.remove("monitor-1.png")
 
     fmt = "sct-{mon}-{width}x{height}.png"
     for opt in ("-o", "--out"):
         main(opt, fmt)
-        out, _ = capsys.readouterr()
+        captured = capsys.readouterr()
         with mss(display=os.getenv("DISPLAY")) as sct:
-            for mon, (monitor, line) in enumerate(zip(sct.monitors[1:], out.splitlines()), 1):
+            for mon, (monitor, line) in enumerate(zip(sct.monitors[1:], captured.out.splitlines()), 1):
                 filename = fmt.format(mon=mon, **monitor)
                 assert line.endswith(filename)
                 assert os.path.isfile(filename)
@@ -127,47 +127,59 @@ def main(*args: str, ret: int = 0) -> None:
     for opt in ("-o", "--out"):
         main("-m 1", opt, fmt)
         filename = fmt.format(mon=1, date=datetime.now())
-        out, _ = capsys.readouterr()
-        assert out.endswith(filename + "\n")
+        captured = capsys.readouterr()
+        assert captured.out.endswith(filename + "\n")
         assert os.path.isfile(filename)
         os.remove(filename)
 
     coordinates = "2,12,40,67"
     filename = "sct-2x12_40x67.png"
     for opt in ("-c", "--coordinates"):
         main(opt, coordinates)
-        out, _ = capsys.readouterr()
-        assert out.endswith(filename + "\n")
+        captured = capsys.readouterr()
+        assert captured.out.endswith(filename + "\n")
         assert os.path.isfile(filename)
         os.remove(filename)
 
     coordinates = "2,12,40"
     for opt in ("-c", "--coordinates"):
         main(opt, coordinates, ret=2)
-        out, _ = capsys.readouterr()
-        assert out == "Coordinates syntax: top, left, width, height\n"
+        captured = capsys.readouterr()
+        assert captured.out == "Coordinates syntax: top, left, width, height\n"
 
 
+@patch.object(sys, "argv", new=[])  # Prevent side effects while testing
 @patch("mss.base.MSSBase.monitors", new=[])
 @pytest.mark.parametrize("quiet", [False, True])
 def test_entry_point_error(quiet: bool, capsys):
-    from mss.__main__ import main as entry_point
-
     def main(*args: str) -> int:
         if quiet:
             args = args + ("--quiet",)
         return entry_point(*args)
 
     if quiet:
         assert main() == 1
-        out, err = capsys.readouterr()
-        assert not out
-        assert not err
+        captured = capsys.readouterr()
+        assert not captured.out
+        assert not captured.err
     else:
         with pytest.raises(ScreenShotError):
             main()
 
 
+def test_entry_point_with_no_argument(capsys):
+    # Make sure to fail if arguments are not handled
+    with patch("mss.factory.mss", new=Mock(side_effect=RuntimeError("Boom!"))):
+        with patch.object(sys, "argv", ["mss", "--help"]):
+            with pytest.raises(SystemExit) as exc:
+                entry_point()
+            assert exc.value.code == 0
+
+    captured = capsys.readouterr()
+    assert not captured.err
+    assert "usage: mss" in captured.out
+
+
 def test_grab_with_tuple(pixel_ratio: int):
     left = 100
     top = 100