diff --git a/skimage/__init__.py b/skimage/__init__.py
index 5a84dd68..1435892c 100644
--- a/skimage/__init__.py
+++ b/skimage/__init__.py
@@ -71,7 +71,7 @@ except ImportError:
         """This would invoke the skimage test suite, but nose couldn't be
         imported so the test suite can not run.
         """
-        raise ImportError("Could not load nose.  Unit tests not available.")
+        raise ImportError("Could not load nose. Unit tests not available.")
 else:
     def test(verbose=False):
         """Invoke the skimage test suite."""