diff --git a/sknn/ae.py b/sknn/ae.py
index 1c16e57..3298cde 100644
--- a/sknn/ae.py
+++ b/sknn/ae.py
@@ -25,7 +25,7 @@ def __init__(self,
                  units=None,
                  cost='msre',
                  tied_weights=False,
-                 corruption_level=None):
+                 corruption_level=0.5):
 
         assert warning is None, \
             "Specify layer parameters as keyword arguments, not positional arguments."
diff --git a/sknn/tests/test_ae.py b/sknn/tests/test_ae.py
index 0c7f44b..dd5fd80 100644
--- a/sknn/tests/test_ae.py
+++ b/sknn/tests/test_ae.py
@@ -21,12 +21,16 @@ def test_FitData(self):
 class TestParameters(unittest.TestCase):
     
     def test_CostFunctions(self):
+        X = numpy.zeros((8,4))
         for t in ['msre', 'mbce']:
-            AE(layers=[L("Sigmoid", units=8, cost=t)])
+            ae = AE(layers=[L("Sigmoid", units=8, cost=t)], n_iter=1)
+            ae.fit(X)
 
     def test_LayerTypes(self):
+        X = numpy.zeros((8,4))
         for l in ['autoencoder', 'denoising']:
-            AE(layers=[L("Sigmoid", type=l, units=8)])
+            ae = AE(layers=[L("Sigmoid", type=l, units=8)])
+            ae.fit(X)
 
     def test_UnknownCostFunction(self):
         assert_raises(NotImplementedError, L, "Sigmoid", cost="unknown")