Add a test to validate loading.

Author: brendanburns

util/src/main/java/io/kubernetes/client/util/Yaml.java

@@ -360,7 +360,12 @@ protected NodeTuple representJavaBeanProperty(
   }
 
   /** @return An instantiated SnakeYaml Object. */
-  public static org.yaml.snakeyaml.Yaml getSnakeYaml(Class<?> type) {
+  @Deprecated
+  public static org.yaml.snakeyaml.Yaml getSnakeYaml() {
+    return getSnakeYaml(null);
+  }
+
+  private static org.yaml.snakeyaml.Yaml getSnakeYaml(Class<?> type) {
     if (type != null) {
       return new org.yaml.snakeyaml.Yaml(new CustomConstructor(type), new CustomRepresenter());
     }

util/src/test/java/io/kubernetes/client/util/TestPoJ.java

@@ -0,0 +1,25 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package io.kubernetes.client.util;
+
+public class TestPoJ {
+  private static boolean marker = false;
+
+  public TestPoJ() {
+    marker = true;
+  }
+
+  public static boolean hasBeenConstructed() {
+    return marker;
+  }
+}

util/src/test/java/io/kubernetes/client/util/YamlTest.java

@@ -47,6 +47,8 @@ public class YamlTest {
 
   private static final URL CREATED_TIMESTAMP_FILE = Resources.getResource("test-pod.yaml");
 
+  private static final URL TAGGED_FILE = Resources.getResource("pod-tag.yaml");
+
   private static final String[] kinds =
       new String[] {
         "Pod",
@@ -256,4 +258,26 @@ public void testDateTimeRoundTrip() {
       assertNull("Unexpected exception: " + ex.toString(), ex);
     }
   }
+
+  @Test
+  public void testYamlCantConstructObjects() {
+    try {
+      String data = Resources.toString(TAGGED_FILE, UTF_8);
+      Object pod = Yaml.load(data);
+    } catch (Exception ex) {
+      // pass
+    }
+    assertFalse("Object should not be constructed!", TestPoJ.hasBeenConstructed());
+  }
+
+  @Test
+  public void testLoadAsYamlCantConstructObjects() {
+    try {
+      String data = Resources.toString(TAGGED_FILE, UTF_8);
+      V1Pod pod = Yaml.loadAs(data, V1Pod.class);
+    } catch (Exception ex) {
+      // pass
+    }
+    assertFalse("Object should not be constructed!", TestPoJ.hasBeenConstructed());
+  }
 }

util/src/test/resources/pod-tag.yaml

@@ -0,0 +1,12 @@
+!!io.kubernetes.client.util.TestPoJ
+apiVersion: v1
+kind: Pod
+metadata:
+  creationTimestamp: "2018-12-23T01:09:18Z"
+  generateName: test-776d6c86cc-
+  labels:
+    app: test
+    app-version: "19911"
+    pod-template-hash: "3328274277"
+  name: test-776d6c86cc-4zwj5
+  namespace: default