1 files changed, 14 insertions, 0 deletions
diff --git a/mllib/src/test/scala/org/apache/spark/ml/classification/DecisionTreeClassifierSuite.scala b/mllib/src/test/scala/org/apache/spark/ml/classification/DecisionTreeClassifierSuite.scala
index 10de50306a..964fcfbdd8 100644
--- a/mllib/src/test/scala/org/apache/spark/ml/classification/DecisionTreeClassifierSuite.scala
+++ b/mllib/src/test/scala/org/apache/spark/ml/classification/DecisionTreeClassifierSuite.scala
@@ -385,6 +385,20 @@ class DecisionTreeClassifierSuite
     testEstimatorAndModelReadWrite(dt, continuousData, allParamSettings ++ Map("maxDepth" -> 0),
       allParamSettings ++ Map("maxDepth" -> 0), checkModelData)
   }
+
+  test("SPARK-20043: " +
+       "ImpurityCalculator builder fails for uppercase impurity type Gini in model read/write") {
+    val rdd = TreeTests.getTreeReadWriteData(sc)
+    val data: DataFrame =
+      TreeTests.setMetadata(rdd, Map.empty[Int, Int], numClasses = 2)
+
+    val dt = new DecisionTreeClassifier()
+      .setImpurity("Gini")
+      .setMaxDepth(2)
+    val model = dt.fit(data)
+
+    testDefaultReadWrite(model)
+  }
 }
 
 private[ml] object DecisionTreeClassifierSuite extends SparkFunSuite {