docs(samples): fix NPE in DeleteMetricDescriptorIT#testDeleteMetricDe…

samples/snippets/src/test/java/com/example/monitoring/CreateAlertPolicyIT.java

@@ -39,6 +39,7 @@ public class CreateAlertPolicyIT {
   private String alertPolicyId;
   private String alertPolicyDisplayName;
   private PrintStream out;
+  private PrintStream originalPrintStream;
 
   private static String requireEnvVar(String varName) {
     String value = System.getenv(varName);
@@ -58,6 +59,7 @@ public void setUp() {
     alertPolicyDisplayName = "alert_policy_name_" + suffix;
     bout = new ByteArrayOutputStream();
     out = new PrintStream(bout);
+    originalPrintStream = System.out;
     System.setOut(out);
   }
 
@@ -66,9 +68,8 @@ public void tearDown() throws IOException {
     // delete an alert policy for clean up
     DeleteAlertPolicy.deleteAlertPolicy(alertPolicyId);
     // restores print statements in the original method
-    bout.reset();
-    out.flush();
     System.out.flush();
+    System.setOut(originalPrintStream);
   }
 
   @Test

samples/snippets/src/test/java/com/example/monitoring/CreateMetricDescriptorIT.java

@@ -39,6 +39,7 @@ public class CreateMetricDescriptorIT {
   private static final String TYPE = "custom.googleapis.com/invoice/paid/amount" + suffix;
   private ByteArrayOutputStream bout;
   private PrintStream out;
+  private PrintStream originalPrintStream;
 
   private static void requireEnvVar(String varName) {
     assertNotNull(
@@ -55,6 +56,7 @@ public static void checkRequirements() {
   public void setUp() {
     bout = new ByteArrayOutputStream();
     out = new PrintStream(bout);
+    originalPrintStream = System.out;
     System.setOut(out);
   }
 
@@ -63,9 +65,8 @@ public void tearDown() throws IOException {
     // clean up
     DeleteMetricDescriptor.deleteMetricDescriptor(PROJECT_ID, TYPE);
     // restores print statements in the original method
-    bout.reset();
-    out.flush();
     System.out.flush();
+    System.setOut(originalPrintStream);
   }
 
   @Test

samples/snippets/src/test/java/com/example/monitoring/DeleteAlertPolicyIT.java

@@ -39,6 +39,7 @@ public class DeleteAlertPolicyIT {
   private String alertPolicyId;
   private String alertPolicyDisplayName;
   private PrintStream out;
+  private PrintStream originalPrintStream;
 
   private static String requireEnvVar(String varName) {
     String value = System.getenv(varName);
@@ -65,15 +66,15 @@ public void setUp() throws IOException {
     alertPolicyId = result.substring(result.indexOf(":") + 1);
     bout.reset();
     out.flush();
+    originalPrintStream = System.out;
     System.setOut(out);
   }
 
   @After
   public void tearDown() {
     // restores print statements in the original method
-    bout.reset();
-    out.flush();
     System.out.flush();
+    System.setOut(originalPrintStream);
   }
 
   @Test

samples/snippets/src/test/java/com/example/monitoring/DeleteMetricDescriptorIT.java

@@ -39,6 +39,7 @@ public class DeleteMetricDescriptorIT {
   private static final String METRIC_TYPE = "custom.googleapis.com/invoice/paid/amount" + suffix;
   private ByteArrayOutputStream bout;
   private PrintStream out;
+  private PrintStream originalPrintStream;
 
   private static void requireEnvVar(String varName) {
     assertNotNull(
@@ -53,18 +54,21 @@ public static void checkRequirements() {
 
   @Before
   public void setUp() throws IOException {
-    CreateMetricDescriptor.createMetricDescriptor(PROJECT_ID, METRIC_TYPE);
     bout = new ByteArrayOutputStream();
     out = new PrintStream(bout);
     System.setOut(out);
+    CreateMetricDescriptor.createMetricDescriptor(PROJECT_ID, METRIC_TYPE);
+    bout.reset();
+    out.flush();
+    originalPrintStream = System.out;
+    System.setOut(out);
   }
 
   @After
   public void tearDown() {
     // restores print statements in the original method
-    bout.reset();
-    out.flush();
     System.out.flush();
+    System.setOut(originalPrintStream);
   }
 
   @Test

samples/snippets/src/test/java/com/example/monitoring/DeleteNotificationChannelIT.java

@@ -41,6 +41,7 @@ public class DeleteNotificationChannelIT {
   private static final String PROJECT_ENV_NAME = "GOOGLE_CLOUD_PROJECT";
   private static String NOTIFICATION_CHANNEL_NAME = "channelname";
   private static NotificationChannel NOTIFICATION_CHANNEL;
+  private PrintStream originalPrintStream;
 
   private static String getProjectId() {
     String projectId = System.getProperty(PROJECT_ENV_NAME, System.getenv(PROJECT_ENV_NAME));
@@ -70,13 +71,16 @@ public static void setupClass() throws IOException {
   public void setUp() {
     bout = new ByteArrayOutputStream();
     out = new PrintStream(bout);
+    originalPrintStream = System.out;
     System.setOut(out);
     System.setProperty("projectId", DeleteNotificationChannelIT.getProjectId());
   }
 
   @After
   public void tearDown() {
-    System.setOut(null);
+    // restores print statements in the original method
+    System.out.flush();
+    System.setOut(originalPrintStream);
   }
 
   @Test

samples/snippets/src/test/java/com/example/monitoring/EnableDisableAlertPolicyIT.java

@@ -36,6 +36,7 @@ public class EnableDisableAlertPolicyIT {
   private String alertPolicyId;
   private String alertPolicyDisplayName;
   private PrintStream out;
+  private PrintStream originalPrintStream;
 
   private static String requireEnvVar(String varName) {
     String value = System.getenv(varName);
@@ -62,6 +63,7 @@ public void setUp() throws IOException {
     alertPolicyId = result.substring(result.indexOf(":") + 1);
     bout.reset();
     out.flush();
+    originalPrintStream = System.out;
     System.setOut(out);
   }
 
@@ -70,9 +72,8 @@ public void tearDown() throws IOException {
     // delete an alert policy for clean up
     DeleteAlertPolicy.deleteAlertPolicy(alertPolicyId);
     // restores print statements in the original method
-    bout.reset();
-    out.flush();
     System.out.flush();
+    System.setOut(originalPrintStream);
   }
 
   @Test

samples/snippets/src/test/java/com/example/monitoring/GetAlertPolicyIT.java

@@ -36,6 +36,7 @@ public class GetAlertPolicyIT {
   private String alertPolicyId;
   private String alertPolicyDisplayName;
   private PrintStream out;
+  private PrintStream originalPrintStream;
 
   private static String requireEnvVar(String varName) {
     String value = System.getenv(varName);
@@ -62,6 +63,7 @@ public void setUp() throws IOException {
     alertPolicyId = result.substring(result.indexOf(":") + 1);
     bout.reset();
     out.flush();
+    originalPrintStream = System.out;
     System.setOut(out);
   }
 
@@ -70,9 +72,8 @@ public void tearDown() throws IOException {
     // delete an alert policy for clean up
     DeleteAlertPolicy.deleteAlertPolicy(alertPolicyId);
     // restores print statements in the original method
-    bout.reset();
-    out.flush();
     System.out.flush();
+    System.setOut(originalPrintStream);
   }
 
   @Test

samples/snippets/src/test/java/com/example/monitoring/GetMonitoredResourceIT.java

@@ -36,6 +36,7 @@ public class GetMonitoredResourceIT {
   private static final String PROJECT_ID = System.getenv("GOOGLE_CLOUD_PROJECT");
   private ByteArrayOutputStream bout;
   private PrintStream out;
+  private PrintStream originalPrintStream;
 
   private static void requireEnvVar(String varName) {
     assertNotNull(
@@ -52,12 +53,15 @@ public static void checkRequirements() {
   public void setUp() {
     bout = new ByteArrayOutputStream();
     out = new PrintStream(bout);
+    originalPrintStream = System.out;
     System.setOut(out);
   }
 
   @After
   public void tearDown() {
+    // restores print statements in the original method
     System.out.flush();
+    System.setOut(originalPrintStream);
   }
 
   @Test

samples/snippets/src/test/java/com/example/monitoring/ListAlertPolicyIT.java

@@ -32,6 +32,7 @@ public class ListAlertPolicyIT {
   private static final String PROJECT_ID = requireEnvVar("GOOGLE_CLOUD_PROJECT");
   private ByteArrayOutputStream bout;
   private PrintStream out;
+  private PrintStream originalPrintStream;
 
   private static String requireEnvVar(String varName) {
     String value = System.getenv(varName);
@@ -50,15 +51,15 @@ public static void checkRequirements() {
   public void setUp() {
     bout = new ByteArrayOutputStream();
     out = new PrintStream(bout);
+    originalPrintStream = System.out;
     System.setOut(out);
   }
 
   @After
   public void tearDown() {
     // restores print statements in the original method
-    bout.reset();
-    out.flush();
     System.out.flush();
+    System.setOut(originalPrintStream);
   }
 
   @Test

samples/snippets/src/test/java/com/example/monitoring/ListMetricDescriptorIT.java

@@ -36,6 +36,7 @@ public class ListMetricDescriptorIT {
   private static final String PROJECT_ID = System.getenv("GOOGLE_CLOUD_PROJECT");
   private ByteArrayOutputStream bout;
   private PrintStream out;
+  private PrintStream originalPrintStream;
 
   private static void requireEnvVar(String varName) {
     assertNotNull(
@@ -52,15 +53,15 @@ public static void checkRequirements() {
   public void setUp() {
     bout = new ByteArrayOutputStream();
     out = new PrintStream(bout);
+    originalPrintStream = System.out;
     System.setOut(out);
   }
 
   @After
   public void tearDown() {
     // restores print statements in the original method
-    bout.reset();
-    out.flush();
     System.out.flush();
+    System.setOut(originalPrintStream);
   }
 
   @Test

samples/snippets/src/test/java/com/example/monitoring/ListMonitoredResourcesIT.java

@@ -36,6 +36,7 @@ public class ListMonitoredResourcesIT {
   private static final String PROJECT_ID = System.getenv("GOOGLE_CLOUD_PROJECT");
   private ByteArrayOutputStream bout;
   private PrintStream out;
+  private PrintStream originalPrintStream;
 
   private static void requireEnvVar(String varName) {
     assertNotNull(
@@ -52,12 +53,15 @@ public static void checkRequirements() {
   public void setUp() {
     bout = new ByteArrayOutputStream();
     out = new PrintStream(bout);
+    originalPrintStream = System.out;
     System.setOut(out);
   }
 
   @After
   public void tearDown() {
-    System.setOut(null);
+    // restores print statements in the original method
+    System.out.flush();
+    System.setOut(originalPrintStream);
   }
 
   @Test

samples/snippets/src/test/java/com/example/monitoring/QuickstartSampleIT.java

@@ -35,6 +35,7 @@ public class QuickstartSampleIT {
   private static final String PROJECT_ID = System.getenv("GOOGLE_CLOUD_PROJECT");
   private ByteArrayOutputStream bout;
   private PrintStream out;
+  private PrintStream originalPrintStream;
 
   private static void requireEnvVar(String varName) {
     assertNotNull(
@@ -51,13 +52,15 @@ public static void checkRequirements() {
   public void setUp() {
     bout = new ByteArrayOutputStream();
     out = new PrintStream(bout);
+    originalPrintStream = System.out;
     System.setOut(out);
   }
 
   @After
   public void tearDown() {
-    // clean up
+    // restores print statements in the original method
     System.out.flush();
+    System.setOut(originalPrintStream);
   }
 
   @Test

samples/snippets/src/test/java/com/example/monitoring/TimeSeriesIT.java

@@ -38,6 +38,7 @@ public class TimeSeriesIT {
       String.format("metric.type=\"compute.googleapis.com/instance/cpu/utilization\"");
   private ByteArrayOutputStream bout;
   private PrintStream out;
+  private PrintStream originalPrintStream;
 
   private static void requireEnvVar(String varName) {
     assertNotNull(
@@ -54,13 +55,15 @@ public static void checkRequirements() {
   public void setUp() {
     bout = new ByteArrayOutputStream();
     out = new PrintStream(bout);
+    originalPrintStream = System.out;
     System.setOut(out);
   }
 
   @After
   public void tearDown() {
-    System.setOut(null);
-    bout.reset();
+    // restores print statements in the original method
+    System.out.flush();
+    System.setOut(originalPrintStream);
   }
 
   @Test

samples/snippets/src/test/java/com/example/monitoring/UpdateAlertPolicyIT.java

@@ -39,6 +39,7 @@ public class UpdateAlertPolicyIT {
   private String alertPolicyId;
   private String alertPolicyDisplayName;
   private PrintStream out;
+  private PrintStream originalPrintStream;
 
   private static String requireEnvVar(String varName) {
     String value = System.getenv(varName);
@@ -65,6 +66,7 @@ public void setUp() throws IOException {
     alertPolicyId = result.substring(result.indexOf(":") + 1);
     bout.reset();
     out.flush();
+    originalPrintStream = System.out;
     System.setOut(out);
   }
 
@@ -73,9 +75,8 @@ public void tearDown() throws IOException {
     // delete an alert policy for clean up
     DeleteAlertPolicy.deleteAlertPolicy(alertPolicyId);
     // restores print statements in the original method
-    bout.reset();
-    out.flush();
     System.out.flush();
+    System.setOut(originalPrintStream);
   }
 
   @Test