Add topic checker

Added a method to check the readiness of a bidirectional topic.

Issue-ID: POLICY-3531
Change-Id: I2fefae7ba1ea5ed9ed33140717d05828e6dec94d
Signed-off-by: Jim Hahn <jrh3@att.com>

1 files changed, 264 insertions, 0 deletions

diff --git a/policy-endpoints/src/test/java/org/onap/policy/common/endpoints/event/comm/client/BidirectionalTopicClientTest.java b/policy-endpoints/src/test/java/org/onap/policy/common/endpoints/event/comm/client/BidirectionalTopicClientTest.java
index cfb65e16..2605c14b 100644
--- a/policy-endpoints/src/test/java/org/onap/policy/common/endpoints/event/comm/client/BidirectionalTopicClientTest.java
+++ b/policy-endpoints/src/test/java/org/onap/policy/common/endpoints/event/comm/client/BidirectionalTopicClientTest.java
@@ -20,6 +20,7 @@
 
 package org.onap.policy.common.endpoints.event.comm.client;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
@@ -28,16 +29,24 @@ import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertTrue;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.atLeast;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 import java.util.Arrays;
 import java.util.Properties;
+import java.util.concurrent.Semaphore;
+import java.util.concurrent.TimeUnit;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+import org.junit.After;
 import org.junit.AfterClass;
 import org.junit.Before;
 import org.junit.BeforeClass;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
 import org.mockito.Mock;
 import org.mockito.junit.MockitoJUnitRunner;
 import org.onap.policy.common.endpoints.event.comm.Topic.CommInfrastructure;
@@ -46,11 +55,18 @@ import org.onap.policy.common.endpoints.event.comm.TopicEndpointManager;
 import org.onap.policy.common.endpoints.event.comm.TopicListener;
 import org.onap.policy.common.endpoints.event.comm.TopicSink;
 import org.onap.policy.common.endpoints.event.comm.TopicSource;
+import org.onap.policy.common.utils.coder.Coder;
+import org.onap.policy.common.utils.coder.CoderException;
+import org.onap.policy.common.utils.coder.StandardCoder;
 
 @RunWith(MockitoJUnitRunner.class)
 public class BidirectionalTopicClientTest {
+    private static final Coder coder = new StandardCoder();
+    private static final long MAX_WAIT_MS = 5000;
+    private static final long SHORT_WAIT_MS = 1;
     private static final String SINK_TOPIC = "my-sink-topic";
     private static final String SOURCE_TOPIC = "my-source-topic";
+    private static final String MY_TEXT = "my-text";
 
     private static final CommInfrastructure SINK_INFRA = CommInfrastructure.UEB;
     private static final CommInfrastructure SOURCE_INFRA = CommInfrastructure.NOOP;
@@ -64,7 +80,10 @@ public class BidirectionalTopicClientTest {
     @Mock
     private TopicListener listener;
 
+    private MyMessage theMessage;
+
     private BidirectionalTopicClient client;
+    private Context context;
 
     /**
      * Configures the endpoints.
@@ -104,7 +123,16 @@ public class BidirectionalTopicClientTest {
         when(endpoint.getTopicSources(any())).thenReturn(Arrays.asList());
         when(endpoint.getTopicSources(Arrays.asList(SOURCE_TOPIC))).thenReturn(Arrays.asList(source));
 
+        theMessage = new MyMessage(MY_TEXT);
+
         client = new BidirectionalTopicClient2(SINK_TOPIC, SOURCE_TOPIC);
+
+        context = new Context();
+    }
+
+    @After
+    public void tearDown() {
+        context.stop();
     }
 
     @Test
@@ -169,6 +197,151 @@ public class BidirectionalTopicClientTest {
         assertNotSame(source, client.getSource());
     }
 
+    @Test
+    public void testAwaitReceipt() throws Exception {
+        context.start(theMessage);
+        assertThat(context.awaitSend(1)).isTrue();
+
+        verify(source).register(any());
+        verify(sink, atLeast(1)).send(any());
+        assertThat(context.checker.isReady()).isFalse();
+
+        inject(theMessage);
+
+        verifyReceipt();
+    }
+
+    @Test
+    public void testAwaitReceipt_AlreadyDone() throws Exception {
+        context.start(theMessage);
+        assertThat(context.awaitSend(1)).isTrue();
+
+        inject(theMessage);
+
+        verifyReceipt();
+
+        // calling again should result in "true" again, without injecting message
+        context.start(theMessage);
+        verifyReceipt();
+    }
+
+    @Test
+    public void testAwaitReceipt_MessageDoesNotMatch() throws Exception {
+        context.start(theMessage);
+        assertThat(context.awaitSend(1)).isTrue();
+
+        // non-matching message
+        inject("{}");
+
+        // wait for a few more calls to "send" and then inject a matching message
+        assertThat(context.awaitSend(3)).isTrue();
+        inject(theMessage);
+
+        verifyReceipt();
+    }
+
+    @Test
+    public void testAwaitReceipt_DecodeFails() throws Exception {
+        context.start(theMessage);
+        assertThat(context.awaitSend(1)).isTrue();
+
+        // force a failure and inject the message
+        context.forceDecodeFailure = true;
+        inject(theMessage);
+
+        assertThat(context.awaitDecodeFailure()).isTrue();
+
+        // no more failures
+        context.forceDecodeFailure = false;
+        inject(theMessage);
+
+        verifyReceipt();
+    }
+
+    @Test
+    public void testAwaitReceipt_Interrupted() throws InterruptedException {
+        context.start(theMessage);
+        assertThat(context.awaitSend(1)).isTrue();
+
+        context.interrupt();
+
+        verifyNoReceipt();
+    }
+
+    @Test
+    public void testAwaitReceipt_MultipleLoops() throws Exception {
+        context.start(theMessage);
+
+        // wait for multiple "send" calls
+        assertThat(context.awaitSend(3)).isTrue();
+
+        inject(theMessage);
+
+        verifyReceipt();
+    }
+
+    @Test
+    public void testStop() throws InterruptedException {
+        context.start(theMessage);
+        assertThat(context.awaitSend(1)).isTrue();
+
+        context.stop();
+
+        verifyNoReceipt();
+    }
+
+    /**
+     * Verifies that awaitReceipt() returns {@code true}.
+     *
+     * @throws InterruptedException if interrupted while waiting for the thread to
+     *         terminate
+     */
+    private void verifyReceipt() throws InterruptedException {
+        assertThat(context.join()).isTrue();
+        assertThat(context.result).isTrue();
+        assertThat(context.exception).isNull();
+        assertThat(context.checker.isReady()).isTrue();
+
+        verify(source).unregister(any());
+    }
+
+    /**
+     * Verifies that awaitReceipt() returns {@code false}.
+     *
+     * @throws InterruptedException if interrupted while waiting for the thread to
+     *         terminate
+     */
+    private void verifyNoReceipt() throws InterruptedException {
+        assertThat(context.join()).isTrue();
+        assertThat(context.result).isFalse();
+        assertThat(context.exception).isNull();
+        assertThat(context.checker.isReady()).isFalse();
+
+        verify(source).unregister(any());
+    }
+
+    /**
+     * Injects a message into the source topic.
+     *
+     * @param message message to be injected
+     * @throws CoderException if the message cannot be encoded
+     */
+    private void inject(MyMessage message) throws CoderException {
+        inject(coder.encode(message));
+    }
+
+    /**
+     * Injects a message into the source topic.
+     *
+     * @param message message to be injected
+     */
+    private void inject(String message) {
+        ArgumentCaptor<TopicListener> cap = ArgumentCaptor.forClass(TopicListener.class);
+        verify(source).register(cap.capture());
+
+        cap.getValue().onTopicEvent(SOURCE_INFRA, SOURCE_TOPIC, message);
+    }
+
 
     /**
      * BidirectionalTopicClient with some overrides.
@@ -185,4 +358,95 @@ public class BidirectionalTopicClientTest {
             return endpoint;
         }
     }
+
+    private class Context {
+        private Thread thread;
+        private boolean result;
+        private Exception exception;
+        private boolean forceDecodeFailure;
+
+        // released every time the checker publishes a message
+        private final Semaphore sendSem = new Semaphore(0);
+
+        // released every time a message-decode fails
+        private final Semaphore decodeFailedSem = new Semaphore(0);
+
+        private final BidirectionalTopicClient2 checker;
+
+        public Context() throws BidirectionalTopicClientException {
+
+            checker = new BidirectionalTopicClient2(SINK_TOPIC, SOURCE_TOPIC) {
+
+                @Override
+                public boolean send(String messageText) {
+                    boolean result = super.send(messageText);
+                    sendSem.release();
+                    return result;
+                }
+
+                @Override
+                protected <T> T decode(String msg, Class<? extends T> clazz) throws CoderException {
+                    if (forceDecodeFailure) {
+                        throw new CoderException("expected exception");
+                    }
+
+                    return super.decode(msg, clazz);
+                }
+
+                @Override
+                protected void decodeFailed() {
+                    super.decodeFailed();
+                    decodeFailedSem.release();
+                }
+            };
+        }
+
+        /**
+         * Starts the thread.
+         *
+         * @param message message to be sent to the sink topic
+         */
+        public void start(MyMessage message) {
+            thread = new Thread() {
+                @Override
+                public void run() {
+                    try {
+                        result = checker.awaitReady(message, SHORT_WAIT_MS);
+                    } catch (Exception e) {
+                        exception = e;
+                    }
+                }
+            };
+            thread.setDaemon(true);
+            thread.start();
+        }
+
+        public void stop() {
+            checker.stopWaiting();
+        }
+
+        public boolean join() throws InterruptedException {
+            thread.join(MAX_WAIT_MS);
+            return !thread.isAlive();
+        }
+
+        public void interrupt() {
+            thread.interrupt();
+        }
+
+        public boolean awaitSend(int npermits) throws InterruptedException {
+            return sendSem.tryAcquire(npermits, MAX_WAIT_MS, TimeUnit.MILLISECONDS);
+        }
+
+        public boolean awaitDecodeFailure() throws InterruptedException {
+            return decodeFailedSem.tryAcquire(MAX_WAIT_MS, TimeUnit.MILLISECONDS);
+        }
+    }
+
+    @Data
+    @NoArgsConstructor
+    @AllArgsConstructor
+    public static class MyMessage {
+        private String text;
+    }
 }