Ensure only a single task is created

KAFKA-62

Author: rozza

src/integrationTest/java/com/mongodb/kafka/connect/embedded/EmbeddedKafka.java

@@ -238,7 +238,7 @@ public void beforeAll(final ExtensionContext context) throws Exception {
 
     @Override
     public void afterEach(final ExtensionContext context) throws InterruptedException {
-        deleteTopicsAndWait(Duration.ofMinutes(2));
+        deleteTopicsAndWait(Duration.ofMinutes(4));
         deleteSinkConnector();
         deleteSourceConnector();
     }

src/main/java/com/mongodb/kafka/connect/MongoSinkConnector.java

@@ -18,7 +18,8 @@
 
 package com.mongodb.kafka.connect;
 
-import java.util.ArrayList;
+import static java.util.Collections.singletonList;
+
 import java.util.List;
 import java.util.Map;
 
@@ -49,11 +50,7 @@ public Class<? extends Task> taskClass() {
 
     @Override
     public List<Map<String, String>> taskConfigs(final int maxTasks) {
-        List<Map<String, String>> taskConfigs = new ArrayList<>(maxTasks);
-        for (int i = 0; i < maxTasks; i++) {
-            taskConfigs.add(settings);
-        }
-        return taskConfigs;
+        return singletonList(settings);
     }
 
     @Override

src/main/java/com/mongodb/kafka/connect/MongoSourceConnector.java

@@ -16,7 +16,8 @@
 
 package com.mongodb.kafka.connect;
 
-import java.util.ArrayList;
+import static java.util.Collections.singletonList;
+
 import java.util.List;
 import java.util.Map;
 
@@ -43,11 +44,7 @@ public Class<? extends Task> taskClass() {
 
     @Override
     public List<Map<String, String>> taskConfigs(final int maxTasks) {
-        List<Map<String, String>> taskConfigs = new ArrayList<>(maxTasks);
-        for (int i = 0; i < maxTasks; i++) {
-            taskConfigs.add(settings);
-        }
-        return taskConfigs;
+        return singletonList(settings);
     }
 
     @Override

src/test/java/com/mongodb/kafka/connect/MongoSinkConnnectorTest.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2008-present MongoDB, Inc.
+ *
+ * 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.
+ *
+ * Original Work: Apache License, Version 2.0, Copyright 2017 Hans-Peter Grahsl.
+ */
+
+package com.mongodb.kafka.connect;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.platform.runner.JUnitPlatform;
+import org.junit.runner.RunWith;
+
+import com.mongodb.kafka.connect.sink.MongoSinkConfig;
+import com.mongodb.kafka.connect.sink.MongoSinkTask;
+
+@RunWith(JUnitPlatform.class)
+class MongoSinkConnnectorTest {
+
+    @Test
+    @DisplayName("Should return the expected version")
+    void testVersion() {
+        MongoSinkConnector sinkConnector = new MongoSinkConnector();
+
+        assertEquals(Versions.VERSION, sinkConnector.version());
+    }
+
+    @Test
+    @DisplayName("test task class")
+    void testTaskClass() {
+        MongoSinkConnector sinkConnector = new MongoSinkConnector();
+
+        assertEquals(MongoSinkTask.class, sinkConnector.taskClass());
+    }
+
+    @Test
+    @DisplayName("test task configs")
+    void testConfig() {
+        MongoSinkConnector sinkConnector = new MongoSinkConnector();
+
+        assertEquals(MongoSinkConfig.CONFIG, sinkConnector.config());
+    }
+
+    @Test
+    @DisplayName("test task configs")
+    void testTaskConfigs() {
+        MongoSinkConnector sinkConnector = new MongoSinkConnector();
+        Map<String, String> configMap = new HashMap<String, String>() {{
+            put("a", "1");
+            put("b", "2");
+        }};
+        sinkConnector.start(configMap);
+        List<Map<String, String>> taskConfigs = sinkConnector.taskConfigs(100);
+
+        assertEquals(1, taskConfigs.size());
+        assertEquals(configMap, taskConfigs.get(0));
+    }
+}

src/test/java/com/mongodb/kafka/connect/MongoSourceConnnectorTest.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2008-present MongoDB, Inc.
+ *
+ * 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.
+ *
+ * Original Work: Apache License, Version 2.0, Copyright 2017 Hans-Peter Grahsl.
+ */
+
+package com.mongodb.kafka.connect;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.platform.runner.JUnitPlatform;
+import org.junit.runner.RunWith;
+
+import com.mongodb.kafka.connect.source.MongoSourceConfig;
+import com.mongodb.kafka.connect.source.MongoSourceTask;
+
+@RunWith(JUnitPlatform.class)
+class MongoSourceConnnectorTest {
+
+    @Test
+    @DisplayName("Should return the expected version")
+    void testVersion() {
+        MongoSourceConnector sourceConnector = new MongoSourceConnector();
+
+        assertEquals(Versions.VERSION, sourceConnector.version());
+    }
+
+    @Test
+    @DisplayName("test task class")
+    void testTaskClass() {
+        MongoSourceConnector sourceConnector = new MongoSourceConnector();
+
+        assertEquals(MongoSourceTask.class, sourceConnector.taskClass());
+    }
+
+    @Test
+    @DisplayName("test task configs")
+    void testConfig() {
+        MongoSourceConnector sourceConnector = new MongoSourceConnector();
+
+        assertEquals(MongoSourceConfig.CONFIG, sourceConnector.config());
+    }
+
+    @Test
+    @DisplayName("test task configs")
+    void testTaskConfigs() {
+        MongoSourceConnector sourceConnector = new MongoSourceConnector();
+        Map<String, String> configMap = new HashMap<String, String>() {{
+            put("a", "1");
+            put("b", "2");
+        }};
+        sourceConnector.start(configMap);
+        List<Map<String, String>> taskConfigs = sourceConnector.taskConfigs(100);
+
+        assertEquals(1, taskConfigs.size());
+        assertEquals(configMap, taskConfigs.get(0));
+    }
+}