Tests: Add software tests for "Magics.selfcheck" and "Magics.main"

Magics/__main__.py

@@ -38,5 +38,5 @@ def main(argv=None):
         )
 
 
-if __name__ == "__main__":
+if __name__ == "__main__":  # pragma: nocover
     main()

tests/test_main.py

@@ -0,0 +1,42 @@
+import re
+import sys
+
+import pytest
+
+from Magics.__main__ import main, selfcheck
+
+
+def test_selfcheck(capsys):
+    selfcheck()
+
+    stdout, stderr = capsys.readouterr()
+
+    assert "Found:" in stdout
+    assert "Library:" in stdout
+    assert "Magics home:" in stdout
+    assert "Your system is ready." in stdout
+
+    assert "You are using an old version of magics" not in stdout
+
+
+def test_main_success(capsys):
+    sys.argv = ["program", "selfcheck"]
+    main()
+    stdout, stderr = capsys.readouterr()
+    assert "Your system is ready." in stdout
+
+
+def test_main_failure_no_command(capsys):
+    sys.argv = ["program"]
+    with pytest.raises(SystemExit) as ex:
+        main()
+    ex.match("2")
+    stdout, stderr = capsys.readouterr()
+    assert "program: error: the following arguments are required: command" in stderr
+
+
+def test_main_failure_unknown_command(capsys):
+    sys.argv = ["program", "foobar"]
+    with pytest.raises(RuntimeError) as ex:
+        main()
+    ex.match(re.escape("Command not recognised 'foobar'. See usage with --help."))