Added the junit test for the ObjectmanagerFactory class.

Author: taojing2002

src/main/java/org/dataone/cn/indexer/object/ObjectManagerFactory.java

@@ -11,7 +11,8 @@
  */
 public class ObjectManagerFactory {
     private static volatile ObjectManager manager = null;
-    private static String className = "org.dataone.cn.indexer.object.hashstore.HashStoreObjManager";
+    private static final String DEFAULT_ClASS_NAME = "org.dataone.cn.indexer.object.hashstore"
+        + ".HashStoreObjManager";
     private static Log logger = LogFactory.getLog(ObjectManagerFactory.class);
     private static final String OBJECT_MANAGER_CLASSNAME_ENV =
         "DATAONE_INDEXER_OBJECT_MANAGER_CLASSNAME";
@@ -32,6 +33,7 @@ public static ObjectManager getObjectManager()
         throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException,
         InstantiationException, IllegalAccessException {
         String classNameFromEnv = System.getenv(OBJECT_MANAGER_CLASSNAME_ENV);
+        String className = DEFAULT_ClASS_NAME;
         if (classNameFromEnv != null && !classNameFromEnv.isBlank()) {
             logger.debug("The ObjectManager class name form env variable "
                             + OBJECT_MANAGER_CLASSNAME_ENV + " is " + classNameFromEnv);
@@ -49,4 +51,11 @@ public static ObjectManager getObjectManager()
         }
         return manager;
     }
+
+    /**
+     * This method is for testing only
+     */
+    protected static void resetManagerNull() {
+        manager = null;
+    }
 }

src/test/java/org/dataone/cn/indexer/object/ObjectManagerFactoryTest.java

@@ -0,0 +1,48 @@
+package org.dataone.cn.indexer.object;
+
+import org.dataone.cn.indexer.object.hashstore.HashStoreObjManager;
+import org.junit.Rule;
+import org.junit.Test;
+import uk.org.webcompere.systemstubs.rules.EnvironmentVariablesRule;
+
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+/**
+ * A Junit test class for ObjectManagerFactory
+ * @author Tao
+ */
+public class ObjectManagerFactoryTest {
+
+    private static final String envName = "DATAONE_INDEXER_OBJECT_MANAGER_CLASSNAME";
+    @Rule
+    public EnvironmentVariablesRule environmentVariablesClassName =
+        new EnvironmentVariablesRule(envName, null);
+    /**
+     * Test to create a HashStoreObjManager
+     * @throws Exception
+     */
+    @Test
+    public void testHashStoreObjManager() throws Exception {
+        environmentVariablesClassName.set(envName, null);
+        ObjectManagerFactory.resetManagerNull();
+        ObjectManager manager = ObjectManagerFactory.getObjectManager();
+        assertTrue(manager instanceof HashStoreObjManager);
+    }
+
+    /**
+     * Test the failure with a wrong class name
+     * @throws Exception
+     */
+    @Test
+    public void testWrongClassName() throws Exception {
+        environmentVariablesClassName.set(envName, "foo.foo1.className");
+        ObjectManagerFactory.resetManagerNull();
+        try {
+            ObjectManager manager = ObjectManagerFactory.getObjectManager();
+            fail("Test shouldn't get here since the class doesn't exist with the given name.");
+        } catch (Exception e) {
+            assertTrue( e instanceof ClassNotFoundException);
+        }
+    }
+}