paquo.__main__: implement commandline interface

paquo/__main__.py

@@ -1,6 +1,5 @@
 import argparse
 import functools
-import sys
 from contextlib import redirect_stdout
 
 from paquo._cli import subcommand, argument, DirectoryType, \
@@ -25,6 +24,20 @@
 parser.add_argument('--version', action='store_true', help="print version")
 
 
+def main(commandline=None):
+    """main command line argument handling"""
+    args = parser.parse_args(commandline)
+    if args.cmd is None:
+        if args.version:
+            from paquo import __version__
+            print(f"{__version__}")
+        else:
+            parser.print_help()
+    else:
+        return args.cmd_func(args)
+    return 0
+
+
 @subcommand(
     argument('-l', '--list', action='store_true', help="list the paquo config"),
     argument('--default', action='store_true', help="default instead of current config"),
@@ -40,7 +53,7 @@ def config(args, subparser):
     """handle configuration"""
     if not args.list:
         print(subparser.format_help())
-        return
+        return 0
 
     if args.default:
         config_print = config_print_defaults
@@ -59,15 +72,10 @@ def config(args, subparser):
                     config_print()
         except FileExistsError:
             print(f"ERROR: file {out_fn} exists! use --force to overwrite")
-            sys.exit(1)
+            return 1
+    return 0
 
 
-args = parser.parse_args()
-if args.cmd is None:
-    if args.version:
-        from paquo import __version__
-        print(f"{__version__}")
-    else:
-        parser.print_help()
-else:
-    args.cmd_func(args)
+if __name__ == "__main__":  # pragma: no cover
+    import sys
+    sys.exit(main())

paquo/tests/test_main.py

@@ -0,0 +1,44 @@
+import io
+from collections import namedtuple
+from contextlib import redirect_stdout
+from pathlib import Path
+
+import pytest
+
+from paquo.__main__ import main
+
+_Output = namedtuple("_Output", "return_code stdout")
+
+
+def run(func, argv1):
+    f = io.StringIO()
+    with redirect_stdout(f):
+        return_code = func(argv1)
+    return _Output(return_code, f.getvalue().rstrip())
+
+
+def test_no_args():
+    assert main([]) == 0
+
+
+def test_version():
+    from paquo import __version__
+    assert run(main, ['--version']) == (0, __version__)
+
+
+def test_config_cmd(tmp_path):
+    assert main(['config']) == 0  # shows help
+
+    assert run(main, ['config', '-l']).stdout
+    assert run(main, ['config', '-l', '--default']).stdout
+
+    paquo_toml = Path(tmp_path) / ".paquo.toml"
+    paquo_toml.touch()
+
+    # error when folder does not exist
+    with pytest.raises(SystemExit):
+        assert run(main, ['config', '-l', '-o', str(tmp_path / "not-there")])
+    # error when file exists
+    assert run(main, ['config', '-l', '-o', str(tmp_path)]).return_code == 1
+    # force allows overwrite
+    assert run(main, ['config', '-l', '-o', str(tmp_path), '--force']).return_code == 0