diff --git a/tests/test_env_default.py b/tests/test_env_default.py
index 98f7a2d..64622f9 100644
--- a/tests/test_env_default.py
+++ b/tests/test_env_default.py
@@ -6,34 +6,34 @@
 def test_env_default_str():
     os.environ['test_var'] = 'Foo'
     test = EnvDefault('test_var', option_strings='', dest='test_var')
-    assert(test.default == 'Foo')
+    assert test.default == 'Foo'
 
 
 def test_bool_env_default_str():
     os.environ['test_var'] = 'True'
     test = BoolEnvDefault('test_var', option_strings='', dest='test_var')
-    assert(test.default)
+    assert test.default
 
     os.environ['test_var'] = 'true'
     test = BoolEnvDefault('test_var', option_strings='', dest='test_var')
-    assert(test.default)
+    assert test.default
 
     os.environ['test_var'] = '1'
     test = BoolEnvDefault('test_var', option_strings='', dest='test_var')
-    assert(test.default)
+    assert test.default
 
     os.environ['test_var'] = 'False'
     test = BoolEnvDefault('test_var', option_strings='', dest='test_var')
-    assert(not test.default)
+    assert not test.default
 
     os.environ['test_var'] = 'false'
     test = BoolEnvDefault('test_var', option_strings='', dest='test_var')
-    assert(not test.default)
+    assert not test.default
 
     os.environ['test_var'] = '3'
     test = BoolEnvDefault('test_var', option_strings='', dest='test_var')
-    assert(not test.default)
+    assert not test.default
 
     del os.environ['test_var']
     test = BoolEnvDefault('test_var', option_strings='', dest='test_var')
-    assert(not test.default)
+    assert not test.default