Add arg verify

piplicenses.py

@@ -584,22 +584,30 @@ def _split_lines(self, text: Text, width: int) -> List[str]:
 
 class CompatibleArgumentParser(argparse.ArgumentParser):
     def parse_args(self, args=None, namespace=None):
-        args = super(CompatibleArgumentParser, self).parse_args(args,
-                                                                namespace)
-        self._check_code_page(args.filter_code_page)
-
+        args = super().parse_args(args, namespace)
+        self._verify_args(args)
         return args
 
-    @staticmethod
-    def _check_code_page(code_page):
+    def _verify_args(self, args):
+        if args.with_license_file is False and (
+                args.no_license_path is True or
+                args.with_notice_file is True):
+            self.error(
+                "'--no-license-path' and '--with-notice-file' require "
+                "the '--with-license-file' option to be set")
+        if args.filter_strings is False and \
+                args.filter_code_page != 'latin1':
+            self.error(
+                "'--filter-code-page' requires the '--filter-strings' "
+                "option to be set")
         try:
-            codecs.lookup(code_page)
+            codecs.lookup(args.filter_code_page)
         except LookupError:
-            print(("error: invalid code page '%s' given for "
-                   "--filter-code-page;\n"
-                   "       check https://docs.python.org/3/library/"
-                   "codecs.html for valid code pages") % code_page)
-            sys.exit(1)
+            self.error(
+                "invalid code page '%s' given for '--filter-code-page, "
+                "check https://docs.python.org/3/library/codecs.html"
+                "#standard-encodings for valid code pages"
+                % args.filter_code_page)
 
 
 class NoValueEnum(Enum):

test_piplicenses.py

@@ -5,10 +5,13 @@
 import sys
 import unittest
 from email import message_from_string
+from enum import Enum, auto
 
 import docutils.parsers.rst
 import docutils.utils
 import docutils.frontend
+import pytest
+from _pytest.capture import CaptureFixture
 
 import piplicenses
 from piplicenses import (FromArg, __pkgname__, create_parser, output_colored,
@@ -18,7 +21,9 @@
                          select_license_by_source, save_if_needs,
                          RULE_ALL, RULE_FRAME, RULE_HEADER, RULE_NONE,
                          DEFAULT_OUTPUT_FIELDS, SYSTEM_PACKAGES,
-                         LICENSE_UNKNOWN)
+                         LICENSE_UNKNOWN,
+                         CompatibleArgumentParser, value_to_enum_key,
+                         enum_key_to_value)
 
 
 UNICODE_APPENDIX = ""
@@ -547,11 +552,6 @@ def test_with_specified_filter(self):
         packages = list(piplicenses.get_packages(args))
         self.assertNotIn(UNICODE_APPENDIX, packages[-1]["summary"])
 
-    def test_invalid_code_page(self):
-        with self.assertRaises(SystemExit):
-            self.parser.parse_args(["--filter-strings",
-                                    "--filter-code-page=XXX"])
-
 
 class MockStdStream(object):
 
@@ -649,3 +649,54 @@ def test_fail_on(monkeypatch):
     assert '' == mocked_stdout.printed
     assert 'fail-on license MIT License was found for ' \
            'package' in mocked_stderr.printed
+
+
+def test_enums():
+    class TestEnum(Enum):
+        PLAIN = P = auto()
+        JSON_LICENSE_FINDER = JLF = auto()
+
+    assert TestEnum.PLAIN == TestEnum.P
+    assert getattr(TestEnum, value_to_enum_key('jlf')) == \
+        TestEnum.JSON_LICENSE_FINDER
+    assert value_to_enum_key('jlf') == 'JLF'
+    assert value_to_enum_key('json-license-finder') == \
+        'JSON_LICENSE_FINDER'
+    assert enum_key_to_value(TestEnum.JSON_LICENSE_FINDER) == \
+        'json-license-finder'
+    assert enum_key_to_value(TestEnum.PLAIN) == 'plain'
+
+
+@pytest.fixture(scope='package')
+def parser():
+    return create_parser()
+
+
+def test_verify_args(
+        parser: CompatibleArgumentParser, capsys: CaptureFixture):
+    # --with-license-file missing
+    with pytest.raises(SystemExit) as ex:
+        parser.parse_args(['--no-license-path'])
+    capture = capsys.readouterr().err
+    for arg in ('--no-license-path', '--with-license-file'):
+        assert arg in capture
+
+    with pytest.raises(SystemExit) as ex:
+        parser.parse_args(['--with-notice-file'])
+    capture = capsys.readouterr().err
+    for arg in ('--with-notice-file', '--with-license-file'):
+        assert arg in capture
+
+    # --filter-strings missing
+    with pytest.raises(SystemExit) as ex:
+        parser.parse_args(['--filter-code-page=utf8'])
+    capture = capsys.readouterr().err
+    for arg in ('--filter-code-page', '--filter-strings'):
+        assert arg in capture
+
+    # invalid code-page
+    with pytest.raises(SystemExit) as ex:
+        parser.parse_args(['--filter-strings', '--filter-code-page=XX'])
+    capture = capsys.readouterr().err
+    for arg in ('invalid code', '--filter-code-page'):
+        assert arg in capture