demo.MongoTestSupport.java Source code

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Here is the source code for demo.MongoTestSupport.java

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/*
 * Copyright 2013 the original author or authors.
 *
 * 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 demo;

import static org.junit.Assert.fail;

import org.junit.Assume;
import org.junit.Rule;
import org.junit.rules.TestRule;
import org.junit.runner.Description;
import org.junit.runners.model.Statement;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.Assert;

import com.mongodb.MongoClient;
import com.mongodb.MongoClientOptions;

/**
 * Abstract base class for JUnit {@link Rule}s that detect the presence of some external resource. If the resource is
 * indeed present, it will be available during the test lifecycle through {@link #getResource()}. If it is not, tests
 * will either fail or be skipped, depending on the value of system property {@value #EXTERNAL_SERVERS_REQUIRED}.
 *
 * @author Eric Bottard
 * @author Gary Russell
 */
public class MongoTestSupport implements TestRule {

    public static final String EXTERNAL_SERVERS_REQUIRED = "EXTERNAL_SERVERS_REQUIRED";

    protected MongoClient resource;

    private String resourceDescription;

    protected final Logger logger = LoggerFactory.getLogger(this.getClass());

    protected MongoTestSupport(String resourceDescription) {
        Assert.hasText(resourceDescription, "resourceDescription is required");
        this.resourceDescription = resourceDescription;
    }

    @Override
    public Statement apply(final Statement base, Description description) {
        try {
            obtainResource();
        } catch (Exception e) {
            maybeCleanup();

            return failOrSkip(e);
        }

        return new Statement() {

            @Override
            public void evaluate() throws Throwable {
                try {
                    base.evaluate();
                } finally {
                    try {
                        cleanupResource();
                    } catch (Exception ignored) {
                        MongoTestSupport.this.logger.warn("Exception while trying to cleanup proper resource",
                                ignored);
                    }
                }
            }

        };
    }

    private Statement failOrSkip(final Exception e) {
        String serversRequired = System.getenv(EXTERNAL_SERVERS_REQUIRED);
        if ("true".equalsIgnoreCase(serversRequired)) {
            this.logger.error(this.resourceDescription + " IS REQUIRED BUT NOT AVAILABLE", e);
            fail(this.resourceDescription + " IS NOT AVAILABLE");
            // Never reached, here to satisfy method signature
            return null;
        } else {
            this.logger.error(this.resourceDescription + " IS NOT AVAILABLE, SKIPPING TESTS", e);
            return new Statement() {

                @Override
                public void evaluate() throws Throwable {
                    Assume.assumeTrue("Skipping test due to " + MongoTestSupport.this.resourceDescription
                            + " not being available " + e, false);
                }
            };
        }
    }

    private void maybeCleanup() {
        if (this.resource != null) {
            try {
                cleanupResource();
            } catch (Exception ignored) {
                this.logger.warn("Exception while trying to cleanup failed resource", ignored);
            }
        }
    }

    public MongoClient getResource() {
        return this.resource;
    }

    /**
     * Perform cleanup of the {@link #resource} field, which is guaranteed to be non null.
     *
     * @throws Exception any exception thrown by this method will be logged and swallowed
     */
    protected void cleanupResource() throws Exception {
        this.resource.close();
    }

    /**
     * Try to obtain and validate a resource. Implementors should either set the {@link #resource} field with a valid
     * resource and return normally, or throw an exception.
     */
    protected void obtainResource() throws Exception {
        this.resource = new MongoClient("localhost", MongoClientOptions.builder().connectTimeout(300).build());
        this.resource.getDatabaseNames();
    }

}