Add unit tests to throttler (#958)

src/test/java/com/uber/cadence/internal/worker/ThrottlerTest.java

@@ -0,0 +1,104 @@
+/**
+ * Copyright 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * <p>Modifications copyright (C) 2017 Uber Technologies, Inc.
+ *
+ * <p>Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file
+ * except in compliance with the License. A copy of the License is located at
+ *
+ * <p>http://aws.amazon.com/apache2.0
+ *
+ * <p>or in the "license" file accompanying this file. This file 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.uber.cadence.internal.worker;
+
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertThrows;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class ThrottlerTest {
+
+  private Throttler throttler;
+
+  @Before
+  public void setUp() {
+    // Initialize Throttler with a name, rate of 10 messages per second, and interval of 1000ms (1
+    // second)
+    throttler = new Throttler("TestResource", 10, 1000);
+  }
+
+  @Test
+  public void testConstructorWithValidParameters() {
+    // Ensure no exceptions are thrown with valid constructor parameters
+    Throttler throttler = new Throttler("ResourceName", 5.0, 1000);
+    assertNotNull(throttler);
+  }
+
+  @Test
+  public void testConstructorWithNullName() {
+    // Ensure that constructing Throttler with a null name throws IllegalArgumentException
+    assertThrows(IllegalArgumentException.class, () -> new Throttler(null, 10, 1000));
+  }
+
+  @Test
+  public void testConstructorWithZeroRate() {
+    // Ensure that a zero max rate throws an IllegalArgumentException
+    assertThrows(IllegalArgumentException.class, () -> new Throttler("ResourceName", 0, 1000));
+  }
+
+  @Test
+  public void testConstructorWithNegativeRate() {
+    // Ensure that a negative max rate throws an IllegalArgumentException
+    assertThrows(IllegalArgumentException.class, () -> new Throttler("ResourceName", -5, 1000));
+  }
+
+  @Test
+  public void testConstructorWithZeroRateInterval() {
+    // Ensure that a zero rate interval throws an IllegalArgumentException
+    assertThrows(IllegalArgumentException.class, () -> new Throttler("ResourceName", 10, 0));
+  }
+
+  @Test
+  public void testConstructorWithNegativeRateInterval() {
+    // Ensure that a negative rate interval throws an IllegalArgumentException
+    assertThrows(IllegalArgumentException.class, () -> new Throttler("ResourceName", 10, -1000));
+  }
+
+  @Test
+  public void testSetMaxRatePerSecond() {
+    // Verify that setting a valid max rate per second does not throw exceptions and changes the
+    // internal rate
+    throttler.setMaxRatePerSecond(0);
+
+    throttler.setMaxRatePerSecond(5.0);
+    // No explicit output to assert; this test checks that no exceptions occur
+  }
+
+  @Test
+  public void testThrottle() throws InterruptedException {
+    // Test throttle by calling the method several times and verifying no exceptions
+    for (int i = 0; i < 10; i++) {
+      throttler.throttle(); // This test will run without explicit assertions
+    }
+  }
+
+  @Test
+  public void testThrottleAtHighRate() throws InterruptedException {
+    throttler.setMaxRatePerSecond(100000.0); // High rate
+    for (int i = 0; i < 100; i++) {
+      throttler.throttle();
+    }
+  }
+
+  @Test
+  public void testThrottleAtLowRate() throws InterruptedException {
+    throttler.setMaxRatePerSecond(1); // Low rate
+    for (int i = 0; i < 10; i++) {
+      throttler.throttle();
+    }
+  }
+}