diff --git a/.docs/README_template.rst b/.docs/README_template.rst
index 4511f28..d027995 100644
--- a/.docs/README_template.rst
+++ b/.docs/README_template.rst
@@ -2,7 +2,7 @@ igittigitt
 ==========
 
 
-Version v1.0.4 as of 2020-08-14 see `Changelog`_
+Version v1.0.5 as of 2020-08-14 see `Changelog`_
 
 
 .. include:: ./badges.rst
diff --git a/.docs/usage.rst b/.docs/usage.rst
index 102552e..5ffcf1a 100644
--- a/.docs/usage.rst
+++ b/.docs/usage.rst
@@ -9,3 +9,15 @@
     :code: python
     :start-after: # IgnoreParserExamples{{{
     :end-before:  # IgnoreParserExamples}}}
+
+- add a rule by string
+
+.. include:: ../igittigitt/igittigitt.py
+    :code: python
+    :start-after: # add_rule{{{
+    :end-before:  # add_rule}}}
+
+.. include:: ../tests/test_pytest.py
+    :code: python
+    :start-after: # add_rule_Example{{{
+    :end-before:  # add_rule_Example}}}
diff --git a/CHANGES.rst b/CHANGES.rst
index 977cbf4..a136454 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -13,6 +13,10 @@ TODO:
     - documentation
     - asserts for __ALL__ parameters
 
+v1.0.5
+--------
+2020-08-14: fix Windows and MacOs tests
+
 v1.0.4
 --------
 2020-08-13: handle trailing spaces
diff --git a/README.rst b/README.rst
index be79f49..3455a14 100644
--- a/README.rst
+++ b/README.rst
@@ -2,7 +2,7 @@ igittigitt
 ==========
 
 
-Version v1.0.4 as of 2020-08-14 see `Changelog`_
+Version v1.0.5 as of 2020-08-14 see `Changelog`_
 
 |travis_build| |license| |jupyter| |pypi|
 
@@ -152,6 +152,28 @@ Usage
         ...     print(parser)
         <...IgnoreParser object at ...>
 
+- add a rule by string
+
+.. code-block:: python
+
+        def add_rule(self, pattern: str, base_path: PathLikeOrString):
+            """
+            add a rule as a string
+
+            Parameter
+            ---------
+            pattern
+                the pattern
+            base_path
+                since gitignore patterns are relative to a base
+                directory, that needs to be provided here
+            """
+
+.. code-block:: python
+
+        >>> parser = igittigitt.IgnoreParser()
+        >>> parser.add_rule('*.py[cod]', base_path='/home/michael')
+
 Usage from Commandline
 ------------------------
 
@@ -283,6 +305,10 @@ TODO:
     - documentation
     - asserts for __ALL__ parameters
 
+v1.0.5
+--------
+2020-08-14: fix Windows and MacOs tests
+
 v1.0.4
 --------
 2020-08-13: handle trailing spaces
diff --git a/igittigitt/__init__conf__.py b/igittigitt/__init__conf__.py
index 7474f5d..40f5b76 100644
--- a/igittigitt/__init__conf__.py
+++ b/igittigitt/__init__conf__.py
@@ -1,6 +1,6 @@
 name = 'igittigitt'
 title = 'A spec-compliant gitignore parser for Python'
-version = 'v1.0.4'
+version = 'v1.0.5'
 url = 'https://github.com/bitranox/igittigitt'
 author = 'Robert Nowotny'
 author_email = 'bitranox@gmail.com'
@@ -14,7 +14,7 @@ def print_info() -> None:
 
     A spec-compliant gitignore parser for Python
 
-    Version : v1.0.4
+    Version : v1.0.5
     Url     : https://github.com/bitranox/igittigitt
     Author  : Robert Nowotny
     Email   : bitranox@gmail.com""")
diff --git a/igittigitt/igittigitt.py b/igittigitt/igittigitt.py
index 9529bfa..b62a980 100644
--- a/igittigitt/igittigitt.py
+++ b/igittigitt/igittigitt.py
@@ -5,8 +5,11 @@
 import re
 import sys
 from types import TracebackType
-from typing import List, Optional, Tuple, Type
+from typing import Any, List, Optional, Tuple, Type, Union
 
+PathLikeOrString = Union[str, 'os.PathLike[Any]']
+
+__all__ = ('IgnoreParser', )
 
 whitespace_re = re.compile(r"(\\ )+$")
 
@@ -75,7 +78,9 @@ def __exit__(
         pass
 
     def parse_rule_file(
-        self, path_rule_file: os.PathLike, base_dir: Optional[os.PathLike] = None
+        self,
+        rule_file: PathLikeOrString,
+        base_dir: Optional[PathLikeOrString] = None,
     ):
         """
         parse a git ignore file, create rules from a gitignore file
@@ -85,12 +90,28 @@ def parse_rule_file(
         full_path
             the full path to the ignore file
         base_dir
-            todo : good description missing
+            optional base dir, for testing purposes only.
+            the base dir is the parent of the rule file,
+            because rules are relative to the directory
+            were the rule file resides
 
         """
+        if isinstance(rule_file, str):
+            path_rule_file = pathlib.Path(rule_file).resolve()
+        elif isinstance(rule_file, pathlib.Path):
+            path_rule_file = rule_file.resolve()
+        else:
+            raise TypeError('wrong type for "rule_file"')
 
         if base_dir is None:
-            base_dir = os.path.dirname(path_rule_file)
+            path_base_dir = path_rule_file.parent
+        elif isinstance(base_dir, str):
+            path_base_dir = pathlib.Path(base_dir).resolve()
+        elif isinstance(base_dir, pathlib.Path):
+            path_base_dir = base_dir.resolve()
+        else:
+            raise TypeError('wrong type for "base_dir"')
+
         with open(path_rule_file) as ignore_file:
             counter = 0
             for line in ignore_file:
@@ -98,7 +119,7 @@ def parse_rule_file(
                 line = line.rstrip("\n")
                 rule = rule_from_pattern(
                     line,
-                    base_path=pathlib.Path(base_dir).resolve(),
+                    base_path=path_base_dir,
                     source=(path_rule_file, counter),
                 )
                 if rule:
@@ -106,8 +127,24 @@ def parse_rule_file(
                     if rule.negation:
                         self.rules_contains_negation_rule = True
 
-    def add_rule(self, pattern: str, base_path: Optional[os.PathLike] = None):
-        rule = rule_from_pattern(pattern, base_path)
+    # add_rule{{{
+    def add_rule(self, pattern: str, base_path: PathLikeOrString):
+        """
+        add a rule as a string
+
+        Parameter
+        ---------
+        pattern
+            the pattern
+        base_path
+            since gitignore patterns are relative to a base
+            directory, that needs to be provided here
+        """
+        # add_rule}}}
+
+        path_base_path = pathlib.Path(base_path).resolve()
+
+        rule = rule_from_pattern(pattern, path_base_path)
         if rule:
             self.rules.append(rule)
             if rule.negation:
diff --git a/setup.py b/setup.py
index 1648e8c..2ee15c4 100644
--- a/setup.py
+++ b/setup.py
@@ -86,7 +86,7 @@ def get_line_data(line: str) -> str:
 
 setup_kwargs: Dict[str, Any] = dict()
 setup_kwargs["name"] = "igittigitt"
-setup_kwargs["version"] = "v1.0.4"
+setup_kwargs["version"] = "v1.0.5"
 setup_kwargs["url"] = "https://github.com/bitranox/igittigitt"
 setup_kwargs["packages"] = find_packages()
 setup_kwargs["package_data"] = {"igittigitt": []}
diff --git a/tests/test_pytest.py b/tests/test_pytest.py
index 9dc8d48..8d670b0 100644
--- a/tests/test_pytest.py
+++ b/tests/test_pytest.py
@@ -1,5 +1,6 @@
 # STDLIB
 import pathlib
+import platform
 import pytest
 
 # PROJ
@@ -7,155 +8,170 @@
 
 
 @pytest.fixture(scope='function')
-def parser_simple_git_rules():
+def base_path():
+    if platform.system() == 'Windows':
+        return pathlib.Path('C:/Users/michael').resolve()
+    else:
+        return pathlib.Path('/home/michael').resolve()
+
+
+@pytest.fixture(scope='function')
+def parser_simple_git_rules(base_path):
     ignore_parser = igittigitt.IgnoreParser()
-    ignore_parser.add_rule('__pycache__', base_path=pathlib.Path('/home/michael'))
-    ignore_parser.add_rule('*.py[cod]', base_path=pathlib.Path('/home/michael'))
-    ignore_parser.add_rule('.venv/', base_path=pathlib.Path('/home/michael'))
+    # add rules with base path as pathlib.Path
+    ignore_parser.add_rule('__pycache__', base_path=base_path)
+    ignore_parser.add_rule('*.py[cod]', base_path=base_path)
+    ignore_parser.add_rule('.venv/', base_path=base_path)
+    # add rules with base path as string
+    ignore_parser.add_rule('__pycache__', base_path=str(base_path))
+    ignore_parser.add_rule('*.py[cod]', base_path=str(base_path))
+    ignore_parser.add_rule('.venv/', base_path=str(base_path))
+
     return ignore_parser
 
 
 @pytest.fixture(scope='function')
-def parser_test_comments():
+def parser_test_comments(base_path):
     ignore_parser = igittigitt.IgnoreParser()
-    ignore_parser.add_rule('somematch', base_path=pathlib.Path('/home/michael'))
-    ignore_parser.add_rule('#realcomment', base_path=pathlib.Path('/home/michael'))
-    ignore_parser.add_rule('othermatch', base_path=pathlib.Path('/home/michael'))
-    ignore_parser.add_rule('\\#imnocomment', base_path=pathlib.Path('/home/michael'))
+    ignore_parser.add_rule('somematch', base_path=base_path)
+    ignore_parser.add_rule('#realcomment', base_path=base_path)
+    ignore_parser.add_rule('othermatch', base_path=base_path)
+    ignore_parser.add_rule('\\#imnocomment', base_path=base_path)
     return ignore_parser
 
 
 @pytest.fixture(scope='function')
-def parser_test_wildcard():
+def parser_test_wildcard(base_path):
     ignore_parser = igittigitt.IgnoreParser()
-    ignore_parser.add_rule('hello.*', base_path=pathlib.Path('/home/michael'))
+    ignore_parser.add_rule('hello.*', base_path=base_path)
     return ignore_parser
 
 
 @pytest.fixture(scope='function')
-def parser_test_anchored_wildcard():
+def parser_test_anchored_wildcard(base_path):
     ignore_parser = igittigitt.IgnoreParser()
-    ignore_parser.add_rule('/hello.*', base_path=pathlib.Path('/home/michael'))
+    ignore_parser.add_rule('/hello.*', base_path=base_path)
     return ignore_parser
 
 
 @pytest.fixture(scope='function')
-def parser_test_trailing_spaces():
+def parser_test_trailing_spaces(base_path):
     """
     is that really necessary ? Because there should be no files to filter
     with a trailing space on the filesystem ?
 
     """
     ignore_parser = igittigitt.IgnoreParser()
-    ignore_parser.add_rule('ignoretrailingspace ', base_path=pathlib.Path('/home/michael'))
-    ignore_parser.add_rule('notignoredspace\\ ', base_path=pathlib.Path('/home/michael'))
-    ignore_parser.add_rule('partiallyignoredspace\\  ', base_path=pathlib.Path('/home/michael'))
-    ignore_parser.add_rule('partiallyignoredspace2 \\  ', base_path=pathlib.Path('/home/michael'))
-    ignore_parser.add_rule('notignoredmultiplespace\\ \\ \\ ', base_path=pathlib.Path('/home/michael'))
+    ignore_parser.add_rule('ignoretrailingspace ', base_path=base_path)
+    ignore_parser.add_rule('notignoredspace\\ ', base_path=base_path)
+    ignore_parser.add_rule('partiallyignoredspace\\  ', base_path=base_path)
+    ignore_parser.add_rule('partiallyignoredspace2 \\  ', base_path=base_path)
+    ignore_parser.add_rule('notignoredmultiplespace\\ \\ \\ ', base_path=base_path)
     return ignore_parser
 
 
 @pytest.fixture(scope='function')
-def parser_negation_git_rules():
+def parser_negation_git_rules(base_path):
     ignore_parser = igittigitt.IgnoreParser()
-    ignore_parser.add_rule('*.ignore', base_path=pathlib.Path('/home/michael'))
-    ignore_parser.add_rule('!keep.ignore', base_path=pathlib.Path('/home/michael'))
+    ignore_parser.add_rule('*.ignore', base_path=base_path)
+    ignore_parser.add_rule('!keep.ignore', base_path=base_path)
     return ignore_parser
 
 
-def test_simple_rules(parser_simple_git_rules):
-    assert not parser_simple_git_rules.match(pathlib.Path('/home/michael/main.py'))
-    assert not parser_simple_git_rules.match(pathlib.Path('/home/bitranox/main.py'))
-    assert parser_simple_git_rules.match(pathlib.Path('/home/michael/main.pyc'))
-    assert parser_simple_git_rules.match(pathlib.Path('/home/michael/dir/main.pyc'))
-    assert parser_simple_git_rules.match(pathlib.Path('/home/michael/__pycache__'))
-    assert parser_simple_git_rules.match(pathlib.Path('/home/michael/.venv/'))
-    assert parser_simple_git_rules.match(pathlib.Path('/home/michael/.venv/folder'))
-    assert parser_simple_git_rules.match(pathlib.Path('/home/michael/.venv/file.txt'))
-
-    assert not parser_simple_git_rules.match('/home/michael/main.py')
-    assert not parser_simple_git_rules.match('/home/bitranox/main.py')
-    assert parser_simple_git_rules.match('/home/michael/main.pyc')
-    assert parser_simple_git_rules.match('/home/michael/dir/main.pyc')
-    assert parser_simple_git_rules.match('/home/michael/__pycache__')
-    assert parser_simple_git_rules.match('/home/michael/.venv/')
-    assert parser_simple_git_rules.match('/home/michael/.venv/folder')
-    assert parser_simple_git_rules.match('/home/michael/.venv/file.txt')
-
-
-def test_comments(parser_test_comments):
-    assert parser_test_comments.match(pathlib.Path('/home/michael/somematch'))
-    assert not parser_test_comments.match(pathlib.Path('/home/michael/#realcomment'))
-    assert parser_test_comments.match(pathlib.Path('/home/michael/othermatch'))
-    assert parser_test_comments.match(pathlib.Path('/home/michael/#imnocomment'))
-
-    assert parser_test_comments.match('/home/michael/somematch')
-    assert not parser_test_comments.match('/home/michael/#realcomment')
-    assert parser_test_comments.match('/home/michael/othermatch')
-    assert parser_test_comments.match('/home/michael/#imnocomment')
-
-
-def test_wildcard(parser_test_wildcard):
-    assert parser_test_wildcard.match(pathlib.Path('/home/michael/hello.txt'))
-    assert parser_test_wildcard.match(pathlib.Path('/home/michael/hello.foobar/'))
-    assert parser_test_wildcard.match(pathlib.Path('/home/michael/dir/hello.txt'))
-    assert parser_test_wildcard.match(pathlib.Path('/home/michael/hello.'))
-    assert not parser_test_wildcard.match(pathlib.Path('/home/michael/hello'))
-    assert not parser_test_wildcard.match(pathlib.Path('/home/michael/helloX'))
-
-    assert parser_test_wildcard.match('/home/michael/hello.txt')
-    assert parser_test_wildcard.match('/home/michael/hello.foobar/')
-    assert parser_test_wildcard.match('/home/michael/dir/hello.txt')
-    assert parser_test_wildcard.match('/home/michael/hello.')
-    assert not parser_test_wildcard.match('/home/michael/hello')
-    assert not parser_test_wildcard.match('/home/michael/helloX')
-
-
-def test_anchored_wildcard(parser_test_anchored_wildcard):
-    assert parser_test_anchored_wildcard.match(pathlib.Path('/home/michael/hello.txt'))
-    assert parser_test_anchored_wildcard.match(pathlib.Path('/home/michael/hello.c'))
-    assert not parser_test_anchored_wildcard.match(pathlib.Path('/home/michael/a/hello.java'))
-
-    assert parser_test_anchored_wildcard.match('/home/michael/hello.txt')
-    assert parser_test_anchored_wildcard.match('/home/michael/hello.c')
-    assert not parser_test_anchored_wildcard.match('/home/michael/a/hello.java')
-
-
-def test_trailing_spaces(parser_test_trailing_spaces):
+def test_simple_rules(parser_simple_git_rules, base_path):
+    assert not parser_simple_git_rules.match(base_path / 'main.py')
+    # test a path that is outside of the base path
+    assert not parser_simple_git_rules.match(base_path.parent / 'bitranox/main.py')
+    assert parser_simple_git_rules.match(base_path / 'main.pyc')
+    assert parser_simple_git_rules.match(base_path / 'dir/main.pyc')
+    assert parser_simple_git_rules.match(base_path / '__pycache__')
+    assert parser_simple_git_rules.match(base_path / '.venv/')
+    assert parser_simple_git_rules.match(base_path / '.venv/folder')
+    assert parser_simple_git_rules.match(base_path / '.venv/file.txt')
+
+    assert not parser_simple_git_rules.match(str(base_path) + '/main.py')
+    assert not parser_simple_git_rules.match(str(base_path.parent) + '/bitranox/main.py')
+    assert parser_simple_git_rules.match(str(base_path) + '/main.pyc')
+    assert parser_simple_git_rules.match(str(base_path) + '/dir/main.pyc')
+    assert parser_simple_git_rules.match(str(base_path) + '/__pycache__')
+    assert parser_simple_git_rules.match(str(base_path) + '/.venv/')
+    assert parser_simple_git_rules.match(str(base_path) + '/.venv/folder')
+    assert parser_simple_git_rules.match(str(base_path) + '/.venv/file.txt')
+
+
+def test_comments(parser_test_comments, base_path):
+    assert parser_test_comments.match(base_path / 'somematch')
+    assert not parser_test_comments.match(base_path / '#realcomment')
+    assert parser_test_comments.match(base_path / 'othermatch')
+    assert parser_test_comments.match(base_path / '#imnocomment')
+
+    assert parser_test_comments.match(str(base_path) + '/somematch')
+    assert not parser_test_comments.match(str(base_path) + '/#realcomment')
+    assert parser_test_comments.match(str(base_path) + '/othermatch')
+    assert parser_test_comments.match(str(base_path) + '/#imnocomment')
+
+
+def test_wildcard(parser_test_wildcard, base_path):
+    assert parser_test_wildcard.match(base_path / 'hello.txt')
+    assert parser_test_wildcard.match(base_path / 'hello.foobar/')
+    assert parser_test_wildcard.match(base_path / 'dir/hello.txt')
+    assert parser_test_wildcard.match(base_path / 'hello.')
+    assert not parser_test_wildcard.match(base_path / 'hello')
+    assert not parser_test_wildcard.match(base_path / 'helloX')
+
+    assert parser_test_wildcard.match(str(base_path) + '/hello.txt')
+    assert parser_test_wildcard.match(str(base_path) + '/hello.foobar/')
+    assert parser_test_wildcard.match(str(base_path) + '/dir/hello.txt')
+    assert parser_test_wildcard.match(str(base_path) + '/hello.')
+    assert not parser_test_wildcard.match(str(base_path) + '/hello')
+    assert not parser_test_wildcard.match(str(base_path) + '/helloX')
+
+
+def test_anchored_wildcard(parser_test_anchored_wildcard, base_path):
+    assert parser_test_anchored_wildcard.match(base_path / 'hello.txt')
+    assert parser_test_anchored_wildcard.match(base_path / 'hello.c')
+    assert not parser_test_anchored_wildcard.match(base_path / 'a/hello.java')
+
+    assert parser_test_anchored_wildcard.match(str(base_path) + '/hello.txt')
+    assert parser_test_anchored_wildcard.match(str(base_path) + '/hello.c')
+    assert not parser_test_anchored_wildcard.match(str(base_path) + '/a/hello.java')
+
+
+def test_trailing_spaces(parser_test_trailing_spaces, base_path):
     """
     is that really necessary ? Because there should be no files to filter
     with a trailing space on the filesystem ?
 
     """
-    assert parser_test_trailing_spaces.match('/home/michael/ignoretrailingspace')
-    assert not parser_test_trailing_spaces.match('/home/michael/ignoretrailingspace ')
+    assert parser_test_trailing_spaces.match(str(base_path) + '/ignoretrailingspace')
+    assert not parser_test_trailing_spaces.match(str(base_path) + '/ignoretrailingspace ')
 
-    assert parser_test_trailing_spaces.match('/home/michael/partiallyignoredspace ')
-    assert not parser_test_trailing_spaces.match('/home/michael/partiallyignoredspace  ')
-    assert not parser_test_trailing_spaces.match('/home/michael/partiallyignoredspace')
+    assert parser_test_trailing_spaces.match(str(base_path) + '/partiallyignoredspace ')
+    assert not parser_test_trailing_spaces.match(str(base_path) + '/partiallyignoredspace  ')
+    assert not parser_test_trailing_spaces.match(str(base_path) + '/partiallyignoredspace')
 
-    assert parser_test_trailing_spaces.match('/home/michael/partiallyignoredspace2  ')
-    assert not parser_test_trailing_spaces.match('/home/michael/partiallyignoredspace2   ')
-    assert not parser_test_trailing_spaces.match('/home/michael/partiallyignoredspace2 ')
-    assert not parser_test_trailing_spaces.match('/home/michael/partiallyignoredspace2')
+    assert parser_test_trailing_spaces.match(str(base_path) + '/partiallyignoredspace2  ')
+    assert not parser_test_trailing_spaces.match(str(base_path) + '/partiallyignoredspace2   ')
+    assert not parser_test_trailing_spaces.match(str(base_path) + '/partiallyignoredspace2 ')
+    assert not parser_test_trailing_spaces.match(str(base_path) + '/partiallyignoredspace2')
 
-    assert parser_test_trailing_spaces.match('/home/michael/notignoredspace ')
-    assert not parser_test_trailing_spaces.match('/home/michael/notignoredspace')
+    assert parser_test_trailing_spaces.match(str(base_path) + '/notignoredspace ')
+    assert not parser_test_trailing_spaces.match(str(base_path) + '/notignoredspace')
 
-    assert parser_test_trailing_spaces.match('/home/michael/notignoredmultiplespace   ')
-    assert not parser_test_trailing_spaces.match('/home/michael/notignoredmultiplespace')
+    assert parser_test_trailing_spaces.match(str(base_path) + '/notignoredmultiplespace   ')
+    assert not parser_test_trailing_spaces.match(str(base_path) + '/notignoredmultiplespace')
 
 
-def test_negation_rules(parser_negation_git_rules):
-    assert parser_negation_git_rules.match(pathlib.Path('/home/michael/trash.ignore'))
-    assert parser_negation_git_rules.match(pathlib.Path('/home/michael/whatever.ignore'))
-    assert not parser_negation_git_rules.match(pathlib.Path('/home/michael/keep.ignore'))
-    assert not parser_negation_git_rules.match(pathlib.Path('/home/bitranox/keep.ignore'))
+def test_negation_rules(parser_negation_git_rules, base_path):
+    assert parser_negation_git_rules.match(base_path / 'trash.ignore')
+    assert parser_negation_git_rules.match(base_path / 'whatever.ignore')
+    assert not parser_negation_git_rules.match(base_path / 'keep.ignore')
+    assert not parser_negation_git_rules.match(base_path.parent / 'bitranox/keep.ignore')
 
-    assert parser_negation_git_rules.match('/home/michael/trash.ignore')
-    assert parser_negation_git_rules.match('/home/michael/whatever.ignore')
-    assert not parser_negation_git_rules.match('/home/michael/keep.ignore')
-    assert not parser_negation_git_rules.match('/home/bitranox/keep.ignore')
+    assert parser_negation_git_rules.match(str(base_path) + '/trash.ignore')
+    assert parser_negation_git_rules.match(str(base_path) + '/whatever.ignore')
+    assert not parser_negation_git_rules.match(str(base_path) + '/keep.ignore')
+    assert not parser_negation_git_rules.match(str(base_path.parent) + '/bitranox/keep.ignore')
 
 
 def doctest_examples():
@@ -176,6 +192,13 @@ def doctest_examples():
 
     # IgnoreParserExamples}}}
 
+    # add_rule_Example{{{
+    >>> parser = igittigitt.IgnoreParser()
+    >>> parser.add_rule('*.py[cod]', base_path='/home/michael')
+
+    # add_rule_Example}}}
+
+
     """
     pass