diff --git a/tests/test_functionality.py b/tests/test_functionality.py
index 4a98917..a5e7f4f 100644
--- a/tests/test_functionality.py
+++ b/tests/test_functionality.py
@@ -6,85 +6,52 @@ from pargv import parse_args
 
 def test_no_argv():
     with mock.patch('sys.argv', []):
-        args, kwargs = parse_args()
-    assert args == []
-    assert kwargs == {}
+        assert parse_args() == ([], {})
 
 def test_use_sys_argv_by_default():
-    with mock.patch('sys.argv', ['app', 'command', '--option=one', 'two', '--flag', '-io']):
-        args, kwargs = parse_args()
-    assert args == ['app', 'command']
-    assert kwargs == {
-        'option': ['one', 'two'],
-        'flag': True,
-        'i': True,
-        'o': True
-    }
+    with mock.patch('sys.argv', ['argument', '--flag']):
+        assert parse_args() == (['argument'], {'flag': True})
 
 def test_single_positional_argument():
-    args, kwargs = parse_args(['app'])
-    assert args == ['app']
-    assert kwargs == {}
+    assert parse_args(['app']) == (['app'], {})
 
 def test_single_positional_argument_with_underscore():
-    args, kwargs = parse_args(['the-app'])
-    assert args == ['the_app']
-    assert kwargs == {}
+    assert parse_args(['the-app']) == (['the_app'], {})
+    assert parse_args(['a-b']) == (['a_b'], {})
+
+def test_optional_argument_with_underscore():
+    assert parse_args(['--a-b']) == ([], {'a_b': True})
 
 def test_positional_arguments():
-    args, kwargs = parse_args(['app', 'command'])
-    assert args == ['app', 'command']
-    assert kwargs == {}
+    assert parse_args(['app', 'command']) == (['app', 'command'], {})
 
 def test_one_positional_and_optional_argument():
-    args, kwargs = parse_args(['app', '--help'])
-    assert args == ['app']
-    assert kwargs == {'help': True}
+    assert parse_args(['app', '--help']) == (['app'], {'help': True})
 
 def test_one_positional_and_optional_argument_with_values():
-    args, kwargs = parse_args(['app', '--amount=2', '3'])
-    assert args == ['app']
-    assert kwargs == {'amount': ['2', '3']}
+    assert parse_args(['app', '--amount=2', '3']) == (['app'], {'amount': ['2', '3']})
 
 def test_positional_and_optional_arguments():
-    args, kwargs = parse_args(['app', 'command', '--inputfile', '--outputfile'])
-    assert args == ['app', 'command']
-    assert kwargs == {
-        'inputfile': True,
-        'outputfile': True
-        }
+    assert parse_args(['argument', '--help']) == (['argument'], {'help': True})
 
 def test_short_arg_with_single_option():
-    args, kwargs = parse_args(['-a', 'b', '--abc', 'd'])
-    assert args == []
-    assert kwargs == {
-        'a': 'b',
-        'abc': 'd',
-    }
+    assert parse_args(['-a', 'b', '--abc', 'd']) == ([], {'a': 'b', 'abc': 'd'})
 
 def test_short_arg_with_multiple_options():
-    args, kwargs = parse_args(['-i', 'a', 'b', '--input', 'c', 'd'])
-    assert args == []
-    assert kwargs == {
-        'i': ['a', 'b'],
-        'input': ['c', 'd']
-    }
+    assert parse_args(['-i', 'a', 'b']) == ([], {'i': ['a', 'b']})
+
+def test_short_args_with_equals():
+    assert parse_args(['-ab=c']) == ([], {'a': True, 'b': 'c'})
+    assert parse_args(['-ab=c', 'd']) == ([], {'a': True, 'b': ['c', 'd']})
 
 def test_long_args_with_equals():
-    args, kwargs = parse_args(['--input-file=a.py', '--output-file=b.py'])
-    assert args == []
-    assert kwargs == {
-        'input_file': 'a.py',
-        'output_file': 'b.py'
-    }
+    assert parse_args(['--input-file=a.py']) == ([], {'input_file': 'a.py'})
 
 def test_unintended_hyphen():
-    args, kwargs = parse_args(['---triple-hyphen-'])
-    assert args == []
-    assert kwargs == {'_triple_hyphen_': True}
+    assert parse_args(['---triple-hyphen-']) == ([], {'_triple_hyphen_': True})
 
 @pytest.mark.parametrize('argv, args, kwargs', ((
-    ['/pargv/pargv.py', 'command', 'positional', '--flag', '--optional=value', 'test', '--output-file', 'filename', '-flg', 'name', 'name2'],
+    ['/pargv/pargv.py', 'command', 'positional', '--flag', '--optional=value', 'test', '--output-file', 'filename', '-flg=name', 'name2'],
     ['/pargv/pargv.py', 'command', 'positional'],
     {
         'flag': True,
@@ -96,6 +63,4 @@ def test_unintended_hyphen():
     }
 ),))
 def test_all_parameters_at_once(argv, args, kwargs):
-    _args, _kwargs = parse_args(argv)
-    assert _args == args
-    assert _kwargs == kwargs
+    assert parse_args(argv) == (args, kwargs)