Fixes #50 - summary() fails if called a second time. (#107)

* Fixes #50 - summary() fails if called a second time.

Author: pieths

src/python/nimbusml/base_predictor.py

@@ -139,7 +139,7 @@ def summary(self):
         """
         Returns model summary.
         """
-        if hasattr(self, 'model_summary_') and self.model_summary_:
+        if hasattr(self, 'model_summary_') and self.model_summary_ is not None:
             return self.model_summary_
 
         if not hasattr(

src/python/nimbusml/tests/model_summary/test_model_summary.py

@@ -112,6 +112,17 @@ def test_model_summary_not_supported(self):
             pipeline.fit(train_stream, label_column)
             assert_raises(TypeError, pipeline.summary)
 
+    def test_summary_called_back_to_back_on_predictor(self):
+        """
+        When a predictor is fit without using a Pipeline,
+        calling summary() more than once should not throw
+        an exception.
+        """
+        ols = OrdinaryLeastSquaresRegressor()
+        ols.fit([1,2,3,4], [2,4,6,7])
+        ols.summary()
+        ols.summary()
+
 
 if __name__ == '__main__':
     unittest.main()