Added a try/except in case the bounds_transformer is not the correct type + test coverage

Author: Albert Alonso

bayes_opt/bayesian_optimization.py

@@ -123,7 +123,11 @@ def __init__(self, f, pbounds, random_state=None, verbose=2,
         self._verbose = verbose
         self._bounds_transformer = bounds_transformer
         if self._bounds_transformer:
-            self._bounds_transformer.initialize(self._space)
+            try:
+                self._bounds_transformer.initialize(self._space)
+            except (AttributeError, TypeError):
+                raise AssertionError('The transformer must be instance of'
+                                     'DomainTransformer')
 
         super(BayesianOptimization, self).__init__(events=DEFAULT_EVENTS)
 

tests/test_bayesian_optimization.py

@@ -157,6 +157,7 @@ def test_prime_subscriptions():
         ])
 
     test_subscriber = "test_subscriber"
+
     def test_callback(event, instance):
         pass
 
@@ -291,6 +292,13 @@ def reset(self):
     assert tracker.end_count == 3
 
 
+def test_define_wrong_transformer():
+    with pytest.raises(AssertionError):
+        optimizer = BayesianOptimization(target_func, PBOUNDS,
+                                         random_state=np.random.RandomState(1),
+                                         bounds_transformer=3)
+
+
 if __name__ == '__main__':
     r"""
     CommandLine: