diff --git a/skimage/io/inherited_config.py b/skimage/io/inherited_config.py
index 6b989b66..446e6db7 100644
--- a/skimage/io/inherited_config.py
+++ b/skimage/io/inherited_config.py
@@ -116,44 +116,7 @@ class InheritedConfig(dict):
             return False
 
 
-def test_get_non_existent():
-    config = InheritedConfig()
-    assert config.get('size') is None
-
-
-def test_get_simple():
-    config = InheritedConfig({'imread': 'matplotlib'})
-    assert config.get('imread') == 'matplotlib'
-
-
-def test_get_default():
-    config = InheritedConfig()
-    assert config.get('size', 10) == 10
-
-
-def test_get_best():
-    config = InheritedConfig({'size': 0, 'size.text': 1})
-    assert config.get('size.text') == 1
-
-
-def test_get_multi_level():
-    config = InheritedConfig({'size': 0})
-    assert config.get('size.text.title') == 0
-    config['size.text'] = 1
-    assert config.get('size.text.title') == 1
-    config['size.text.title'] = 2
-    assert config.get('size.text.title') == 2
-
-
-def test_contains():
-    config = InheritedConfig({'imread': 'matplotlib'})
-    assert 'imread' in config
-    assert 'imread.jpg' in config
-
-
 if __name__ == '__main__':
     import doctest
-    from numpy import testing
 
     doctest.testmod()
-    testing.run_module_suite()
diff --git a/skimage/io/tests/test_inherited_config.py b/skimage/io/tests/test_inherited_config.py
new file mode 100644
index 00000000..5521da0b
--- /dev/null
+++ b/skimage/io/tests/test_inherited_config.py
@@ -0,0 +1,41 @@
+from skimage.io.inherited_config import InheritedConfig
+
+
+def test_get_non_existent():
+    config = InheritedConfig()
+    assert config.get('size') is None
+
+
+def test_get_simple():
+    config = InheritedConfig({'imread': 'matplotlib'})
+    assert config.get('imread') == 'matplotlib'
+
+
+def test_get_default():
+    config = InheritedConfig()
+    assert config.get('size', 10) == 10
+
+
+def test_get_best():
+    config = InheritedConfig({'size': 0, 'size.text': 1})
+    assert config.get('size.text') == 1
+
+
+def test_get_multi_level():
+    config = InheritedConfig({'size': 0})
+    assert config.get('size.text.title') == 0
+    config['size.text'] = 1
+    assert config.get('size.text.title') == 1
+    config['size.text.title'] = 2
+    assert config.get('size.text.title') == 2
+
+
+def test_contains():
+    config = InheritedConfig({'imread': 'matplotlib'})
+    assert 'imread' in config
+    assert 'imread.jpg' in config
+
+
+if __name__ == '__main__':
+    from numpy import testing
+    testing.run_module_suite()