diff --git a/tests/test_env.py b/tests/test_env.py
index 35b714cb..f2885467 100644
--- a/tests/test_env.py
+++ b/tests/test_env.py
@@ -25,6 +25,7 @@
 @pytest.mark.parametrize(
         'variable,value,raw_value,parse_comments',
         [
+            # parse_comments=True
             ('BOOL_TRUE_STRING_LIKE_BOOL_WITH_COMMENT', 'True', "'True' # comment\n", True),
             ('BOOL_TRUE_BOOL_WITH_COMMENT', 'True ', "True # comment\n", True),
             ('STR_QUOTED_IGNORE_COMMENT', 'foo', " 'foo' # comment\n", True),
@@ -32,6 +33,24 @@
             ('SECRET_KEY_1', '"abc', '"abc#def"\n', True),
             ('SECRET_KEY_2', 'abc', 'abc#def\n', True),
             ('SECRET_KEY_3', 'abc#def', "'abc#def'\n",  True),
+
+            # parse_comments=False
+            ('BOOL_TRUE_STRING_LIKE_BOOL_WITH_COMMENT', "'True' # comment", "'True' # comment\n", False),
+            ('BOOL_TRUE_BOOL_WITH_COMMENT', 'True # comment', "True # comment\n", False),
+            ('STR_QUOTED_IGNORE_COMMENT', " 'foo' # comment", " 'foo' # comment\n", False),
+            ('STR_QUOTED_INCLUDE_HASH', "'foo # with hash' # not comment", "'foo # with hash' # not comment\n", False),
+            ('SECRET_KEY_1', 'abc#def', '"abc#def"\n', False),
+            ('SECRET_KEY_2', 'abc#def', 'abc#def\n', False),
+            ('SECRET_KEY_3', 'abc#def', "'abc#def'\n",  False),
+
+            # parse_comments is not defined (default behavior)
+            ('BOOL_TRUE_STRING_LIKE_BOOL_WITH_COMMENT', "'True' # comment", "'True' # comment\n", None),
+            ('BOOL_TRUE_BOOL_WITH_COMMENT', 'True # comment', "True # comment\n", None),
+            ('STR_QUOTED_IGNORE_COMMENT', " 'foo' # comment", " 'foo' # comment\n", None),
+            ('STR_QUOTED_INCLUDE_HASH', "'foo # with hash' # not comment", "'foo # with hash' # not comment\n", None),
+            ('SECRET_KEY_1', 'abc#def', '"abc#def"\n', None),
+            ('SECRET_KEY_2', 'abc#def', 'abc#def\n', None),
+            ('SECRET_KEY_3', 'abc#def', "'abc#def'\n",  None),
         ],
     )
 def test_parse_comments(variable, value, raw_value, parse_comments):
@@ -46,7 +65,10 @@ def test_parse_comments(variable, value, raw_value, parse_comments):
 
             env = Env()
             Env.ENVIRON = {}
-            env.read_env(env_path, parse_comments=parse_comments)
+            if parse_comments is None:
+                env.read_env(env_path)
+            else:
+                env.read_env(env_path, parse_comments=parse_comments)
 
             assert env(variable) == value