Add unit test for UsageManagerImpl.configureUsageManagerServicePid()

Author: GabrielBrascher

usage/src/main/java/com/cloud/usage/UsageManagerImpl.java

@@ -183,7 +183,7 @@ public class UsageManagerImpl extends ManagerBase implements UsageManager, Runna
     private boolean  usageSnapshotSelection = false;
 
     /**
-     * File "/var/run/cloudstack-usage.service.pid" that stores a string corresponding to the cloudstack-usage.service process id (pid).
+     * File "/var/run/cloudstack-usage.service.pid" that stores a string corresponding to the cloudstack-usage.service process identified (PID).
      */
     private static final String CLOUDSTACK_USAGE_SERVER_SERVICE_PID_FILE = "/var/run/cloudstack-usage.service.pid";
 
@@ -283,20 +283,20 @@ public boolean configure(String name, Map<String, Object> params) throws Configu
             throw new ConfigurationException("Unhandled exception configuring UsageManager " + e.toString());
         }
 
-        configureUsageManagerServicePid();
+        _pid = retrieveUsageManagerServicePid();
         return true;
     }
 
     /**
-     * Sets the '_pid' variable based on the cloudstack-usage.service process id (pid) according to the file /var/run/cloudstack-usage.service.pid. </br>
+     * Retrieves the cloudstack-usage.service PID according to the file /var/run/cloudstack-usage.service.pid.</br>
      * It throws a CloudRuntimeException in the following cases:
      * <ul>
-     *  <li>Cannot find the pid file</li>
-     *  <li>Cannot read the pid file</li>
-     *  <li>NumberUtils.toInt returns 0 (zero) if the conversion fails (pid is null or "")</li>
+     *  <li>Cannot find the PID file</li>
+     *  <li>Cannot read the PID file</li>
+     *  <li>NumberUtils.toInt returns 0 (zero) if the conversion fails (PID is null or "")</li>
      * </ul>
      */
-    protected void configureUsageManagerServicePid() {
+    protected int retrieveUsageManagerServicePid() {
         File usageServicePid = new File(CLOUDSTACK_USAGE_SERVER_SERVICE_PID_FILE);
         if (!usageServicePid.exists()) {
             throw new CloudRuntimeException(String.format("Cannot find file [%s].", CLOUDSTACK_USAGE_SERVER_SERVICE_PID_FILE));
@@ -306,12 +306,13 @@ protected void configureUsageManagerServicePid() {
         }
         try {
             String pidAsString = FileUtils.readFileToString(usageServicePid, Charset.defaultCharset());
-            String pidAsStringWithoutLineSeparator = pidAsString.replace(System.getProperty("line.separator"), "");
-            _pid = NumberUtils.toInt(pidAsStringWithoutLineSeparator);
-            if (_pid == 0) {
+            String pidAsStringWithoutLineSeparator = pidAsString.trim();
+            int pid = NumberUtils.toInt(pidAsStringWithoutLineSeparator);
+            if (pid == 0) {
                 throw new CloudRuntimeException(
                         String.format("Failed to retrieve a valid cloudstack-usage.service pid [file:%s, pid at file:%s]", CLOUDSTACK_USAGE_SERVER_SERVICE_PID_FILE, pidAsString));
             }
+            return pid;
         } catch (IOException e) {
             throw new CloudRuntimeException(e);
         }

usage/src/test/java/com/cloud/usage/UsageManagerImplTest.java

@@ -0,0 +1,84 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// 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 com.cloud.usage;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.charset.Charset;
+
+import org.apache.commons.io.FileUtils;
+import org.apache.commons.lang3.math.NumberUtils;
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.InOrder;
+import org.mockito.Mockito;
+import org.powermock.api.mockito.PowerMockito;
+import org.powermock.core.classloader.annotations.PrepareForTest;
+import org.powermock.modules.junit4.PowerMockRunner;
+
+import com.cloud.utils.exception.CloudRuntimeException;
+
+@RunWith(PowerMockRunner.class)
+@PrepareForTest({FileUtils.class, UsageManagerImpl.class, NumberUtils.class})
+public class UsageManagerImplTest {
+
+    private static final String CLOUDSTACK_USAGE_SERVER_SERVICE_PID_FILE = "/var/run/cloudstack-usage.service.pid";
+    private UsageManagerImpl usageManagerImpl = new UsageManagerImpl();
+
+    @Test
+    public void retrieveUsageManagerServicePidTestCompleteExecutionFlow() throws Exception {
+        prepareAndVerifyTestRetrieveUsageManagerServicePidTest(true, true, 1, 1234, "1234" + System.getProperty("line.separator"));
+    }
+
+    @Test(expected=CloudRuntimeException.class)
+    public void retrieveUsageManagerServicePidTestFileDoesNotExist() throws Exception {
+        prepareAndVerifyTestRetrieveUsageManagerServicePidTest(false, true, 0, 1234, "1234" + System.getProperty("line.separator"));
+    }
+
+    @Test(expected = CloudRuntimeException.class)
+    public void retrieveUsageManagerServicePidTestCannotReadFile() throws Exception {
+        prepareAndVerifyTestRetrieveUsageManagerServicePidTest(true, false, 1, 1234, "1234" + System.getProperty("line.separator"));
+    }
+
+    @Test(expected = CloudRuntimeException.class)
+    public void retrieveUsageManagerServicePidTestPidEqualsToZero() throws Exception {
+        prepareAndVerifyTestRetrieveUsageManagerServicePidTest(true, true, 1, 0, "abc");
+    }
+
+    private void prepareAndVerifyTestRetrieveUsageManagerServicePidTest(boolean fileExists, boolean canReadFile, int timesCanReadIsExecuted, int expectedPid,
+            String readedStringFromFile)
+            throws Exception, IOException {
+        File usageServicePid = Mockito.mock(File.class);
+        PowerMockito.whenNew(File.class).withArguments(CLOUDSTACK_USAGE_SERVER_SERVICE_PID_FILE).thenReturn(usageServicePid);
+
+        Mockito.when(usageServicePid.exists()).thenReturn(fileExists);
+        Mockito.when(usageServicePid.canRead()).thenReturn(canReadFile);
+
+        PowerMockito.mockStatic(FileUtils.class);
+        Mockito.when(FileUtils.readFileToString(usageServicePid, Charset.defaultCharset())).thenReturn(readedStringFromFile);
+
+        int result = usageManagerImpl.retrieveUsageManagerServicePid();
+
+        InOrder inOrder = Mockito.inOrder(usageServicePid);
+        inOrder.verify(usageServicePid).exists();
+        inOrder.verify(usageServicePid, Mockito.times(timesCanReadIsExecuted)).canRead();
+
+        Assert.assertEquals(expectedPid, result);
+    }
+
+}