io.smartspaces.workbench.project.test.JunitTestClassDetector.java Source code

Introduction

Here is the source code for io.smartspaces.workbench.project.test.JunitTestClassDetector.java

Source

/*
 * Copyright (C) 2016 Keith M. Hughes
 * Copyright (C) 2013 Google 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.
 */

package io.smartspaces.workbench.project.test;

import java.io.File;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.logging.Log;
import org.junit.Test;

/**
 * A detector for classes with JUnit tests in them.
 *
 * @author Keith M. Hughes
 */
public class JunitTestClassDetector {

    /**
     * The separator between a file name and the file extension.
     */
    public static final char FILE_EXTENSION_SEPARATOR = '.';

    /**
     * File extension for class files.
     */
    public static final String CLASS_FILE_EXTENSION = FILE_EXTENSION_SEPARATOR + "class";

    /**
     * The separator between the components of a Java package path.
     */
    public static final char CLASS_PACKAGE_COMPONENT_SEPARATOR = '.';

    /**
     * Find all test classes in the given directory.
     *
     * @param directory
     *          the directory to start looking for classes
     * @param classLoader
     *          the classloader for the test classes
     * @param log
     *          logger for the test run
     *
     * @return list of all test classes in the directory
     */
    public List<Class<?>> findTestClasses(File directory, ClassLoader classLoader, Log log) {
        List<Class<?>> testClasses = new ArrayList<Class<?>>();

        scanDirectory(directory, testClasses, new StringBuilder(), classLoader, log);

        return testClasses;
    }

    /**
     * Get all test classes.
     *
     * @param directory
     *          the directory to scan
     * @param testClasses
     *          a list to put the found classes in
     * @param packagePrefix
     *          the prefix for Java packages for files in this directory
     * @param classLoader
     *          the classloader for the test classes
     * @param log
     *          logger for the test run
     */
    private void scanDirectory(File directory, List<Class<?>> testClasses, StringBuilder packagePrefix,
            ClassLoader classLoader, Log log) {
        File[] contents = directory.listFiles();
        if (contents != null) {
            for (File file : contents) {
                String fileName = file.getName();
                if (file.isFile()) {
                    if (fileName.endsWith(CLASS_FILE_EXTENSION)) {
                        testClassForTests(packagePrefix, fileName, classLoader, testClasses, log);
                    }

                } else if (file.isDirectory()) {
                    int length = packagePrefix.length();
                    if (packagePrefix.length() != 0) {
                        packagePrefix.append(CLASS_PACKAGE_COMPONENT_SEPARATOR);
                    }
                    packagePrefix.append(fileName);
                    scanDirectory(file, testClasses, packagePrefix, classLoader, log);
                    packagePrefix.setLength(length);
                }
            }
        }
    }

    /**
     * Test the specified class for any test methods.
     *
     * <p>
     * Superclasses are searched.
     *
     * @param packagePrefix
     *          the prefix package path
     * @param classFileName
     *          the classname for the potential test class
     * @param classLoader
     *          the classloader for test classes
     * @param testClasses
     *          the growing list of classes to test
     * @param log
     *          the logger to use
     */
    private void testClassForTests(StringBuilder packagePrefix, String classFileName, ClassLoader classLoader,
            List<Class<?>> testClasses, Log log) {
        StringBuilder fullyQualifiedClassName = new StringBuilder(packagePrefix);
        if (fullyQualifiedClassName.length() != 0) {
            fullyQualifiedClassName.append(CLASS_PACKAGE_COMPONENT_SEPARATOR);
        }
        fullyQualifiedClassName.append(classFileName.substring(0, classFileName.indexOf(FILE_EXTENSION_SEPARATOR)));
        try {
            Class<?> potentialTestClass = classLoader.loadClass(fullyQualifiedClassName.toString());

            if (isTestClass(potentialTestClass, log)) {
                testClasses.add(potentialTestClass);
            }
        } catch (Exception e) {
            log.error(String.format("Could not test class %s for test methods", fullyQualifiedClassName));
        }
    }

    /**
     * Is the class a JUnit test class?
     *
     * @param potentialTestClass
     *          the class to test
     * @param log
     *          the logger to use
     *
     * @return {@code true} if the class is testable and can be instantiated
     */
    private boolean isTestClass(Class<?> potentialTestClass, Log log) {
        if (potentialTestClass.isInterface() || !classHasPublicConstructor(potentialTestClass, log)) {
            return false;
        }

        // Do not attempt to run tests on abstract test classes.
        if (Modifier.isAbstract(potentialTestClass.getModifiers())) {
            return false;
        }

        for (Method method : potentialTestClass.getMethods()) {
            if (method.isAnnotationPresent(Test.class)) {

                // No need to check any more if we have 1
                return true;
            }
        }

        return false;
    }

    /**
     * Does the class have a no argument public constructor?
     *
     * @param clazz
     *          the class to test
     * @param log
     *          the logger to use
     *
     * @return {@code true} if the class has a public no arg constructor
     */
    private boolean classHasPublicConstructor(Class<?> clazz, Log log) {
        try {
            clazz.getConstructor();

            return true;
        } catch (NoSuchMethodException e) {
            return false;
        } catch (SecurityException e) {
            log.warn(String.format("Potential test class %s caused a security exception. Ignoring.",
                    clazz.getName()), e);

            return false;
        }
    }
}