utils/misc/src/test/java/org/onlab/util/RetryingFunctionTest.java

/*
 * Copyright 2015-present Open Networking Laboratory
 *
 * 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.
 */
package org.onlab.util;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;

/**
 * Unit tests for RetryingFunction.
 *
 */
public class RetryingFunctionTest {

    private int round;

    @Before
    public void setUp() {
        round = 1;
    }

    @After
    public void tearDown() {
        round = 0;
    }

    @Test(expected = RetryableException.class)
    public void testNoRetries() {
        new RetryingFunction<>(this::succeedAfterOneFailure, RetryableException.class, 0, 10).apply(null);
    }

    @Test
    public void testSuccessAfterOneRetry() {
        new RetryingFunction<>(this::succeedAfterOneFailure, RetryableException.class, 1, 10).apply(null);
    }

    @Test(expected = RetryableException.class)
    public void testFailureAfterOneRetry() {
        new RetryingFunction<>(this::succeedAfterTwoFailures, RetryableException.class, 1, 10).apply(null);
    }

    @Test
    public void testFailureAfterTwoRetries() {
        new RetryingFunction<>(this::succeedAfterTwoFailures, RetryableException.class, 2, 10).apply(null);
    }

    @Test(expected = NonRetryableException.class)
    public void testFailureWithNonRetryableFailure() {
        new RetryingFunction<>(this::failCompletely, RetryableException.class, 2, 10).apply(null);
    }

    private String succeedAfterOneFailure(String input) {
        if (round++ <= 1) {
            throw new RetryableException();
        } else {
            return "pass";
        }
    }

    private String succeedAfterTwoFailures(String input) {
        if (round++ <= 2) {
            throw new RetryableException();
        } else {
            return "pass";
        }
    }

    private String failCompletely(String input) {
        if (round++ <= 1) {
            throw new NonRetryableException();
        } else {
            return "pass";
        }
    }

    private class RetryableException extends RuntimeException {
    }

    private class NonRetryableException extends RuntimeException {
    }
}