Add unit test

Author: nezihyigitbasi

parquet-tools/src/main/java/org/apache/parquet/tools/read/SimpleMapRecord.java

@@ -45,10 +45,13 @@ protected Object toJsonObject() {
     return result;
   }
 
-  private String keyToString(Object kvValue) {
+  String keyToString(Object kvValue) {
+    if (kvValue == null) {
+      return "null";
+    }
+
     Class<?> type = kvValue.getClass();
     if (type.isArray()) {
-
       if (type.getComponentType() == boolean.class) {
         return Arrays.toString((boolean[]) kvValue);
       }

parquet-tools/src/test/java/org/apache/parquet/tools/read/TestSimpleMapRecord.java

@@ -0,0 +1,38 @@
+package org.apache.parquet.tools.read;
+
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class TestSimpleMapRecord {
+
+  class TestRecord {
+    private int x;
+    private int y;
+
+    public TestRecord(int x, int y) {
+      this.x = x;
+      this.y = y;
+    }
+
+    @Override
+    public String toString() {
+      return "TestRecord {" + x + "," + y + "}";
+    }
+  }
+
+  @Test
+  public void testBinary() {
+    SimpleMapRecord r = new SimpleMapRecord();
+    Assert.assertEquals("null", r.keyToString(null));
+    Assert.assertEquals("[true, false, true]", r.keyToString(new boolean[]{true, false, true}));
+    Assert.assertEquals("[a, z]", r.keyToString(new char[] { 'a', 'z' }));
+    Assert.assertEquals("[1.0, 3.0]", r.keyToString(new double[]{1.0, 3.0 }));
+    Assert.assertEquals("[2.0, 4.0]", r.keyToString(new double[]{2.0f, 4.0f }));
+    Assert.assertEquals("[100.0, 999.0]", r.keyToString(new double[]{100, 999 }));
+    Assert.assertEquals("[23.0, 37.0]", r.keyToString(new double[] { 23l, 37l }));
+    Assert.assertEquals("[-1.0, -2.0]", r.keyToString(new double[]{(short) -1, (short) -2}));
+    Assert.assertEquals("dGVzdA==", r.keyToString("test".getBytes()));
+    Assert.assertEquals("TestRecord {222,333}", r.keyToString(new TestRecord(222, 333)));
+  }
+}