1 files changed, 27 insertions, 0 deletions
diff --git a/file_utils.py b/file_utils.py
index 525a1af..7270e30 100644
--- a/file_utils.py
+++ b/file_utils.py
@@ -50,26 +50,48 @@ def create_path_if_not_exist(path, on_error=None):
 
 
 def does_file_exist(filename: str) -> bool:
+    """Returns True if a file exists and is a normal file.
+
+    >>> does_file_exist(__file__)
+    True
+    """
     return os.path.exists(filename) and os.path.isfile(filename)
 
 
 def does_directory_exist(dirname: str) -> bool:
+    """Returns True if a file exists and is a directory.
+
+    >>> does_directory_exist('/tmp')
+    True
+    """
     return os.path.exists(dirname) and os.path.isdir(dirname)
 
 
 def does_path_exist(pathname: str) -> bool:
+    """Just a more verbose wrapper around os.path.exists."""
     return os.path.exists(pathname)
 
 
 def get_file_size(filename: str) -> int:
+    """Returns the size of a file in bytes."""
     return os.path.getsize(filename)
 
 
 def is_normal_file(filename: str) -> bool:
+    """Returns True if filename is a normal file.
+
+    >>> is_normal_file(__file__)
+    True
+    """
     return os.path.isfile(filename)
 
 
 def is_directory(filename: str) -> bool:
+    """Returns True if filename is a directory.
+
+    >>> is_directory('/tmp')
+    True
+    """
     return os.path.isdir(filename)
 
 
@@ -274,3 +296,8 @@ class FileWriter(object):
             if (ret >> 8) != 0:
                 raise Exception(f'{cmd} failed, exit value {ret>>8}')
         return None
+
+
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()