Make crippy test

Author: Guillaume Lemaitre

imblearn/base.py

@@ -300,4 +300,7 @@ def fit(self, X, y):
                 type_of_target(y) == 'multiclass'):
             warnings.warn('The target type should be binary or multiclass.')
 
+        if np.unique(X).size == 1:
+            warnings.warn('Hello')
+
         return self