001package org.junit.runner;
002
003import java.util.Comparator;
004
005import org.junit.internal.builders.AllDefaultPossibilitiesBuilder;
006import org.junit.internal.requests.ClassRequest;
007import org.junit.internal.requests.FilterRequest;
008import org.junit.internal.requests.SortingRequest;
009import org.junit.internal.runners.ErrorReportingRunner;
010import org.junit.runner.manipulation.Filter;
011import org.junit.runners.model.InitializationError;
012
013/**
014 * <p>A <code>Request</code> is an abstract description of tests to be run. Older versions of
015 * JUnit did not need such a concept--tests to be run were described either by classes containing
016 * tests or a tree of {@link  org.junit.Test}s. However, we want to support filtering and sorting,
017 * so we need a more abstract specification than the tests themselves and a richer
018 * specification than just the classes.</p>
019 *
020 * <p>The flow when JUnit runs tests is that a <code>Request</code> specifies some tests to be run ->
021 * a {@link org.junit.runner.Runner} is created for each class implied by the <code>Request</code> ->
022 * the {@link org.junit.runner.Runner} returns a detailed {@link org.junit.runner.Description}
023 * which is a tree structure of the tests to be run.</p>
024 *
025 * @since 4.0
026 */
027public abstract class Request {
028    /**
029     * Create a <code>Request</code> that, when processed, will run a single test.
030     * This is done by filtering out all other tests. This method is used to support rerunning
031     * single tests.
032     *
033     * @param clazz the class of the test
034     * @param methodName the name of the test
035     * @return a <code>Request</code> that will cause a single test be run
036     */
037    public static Request method(Class<?> clazz, String methodName) {
038        Description method = Description.createTestDescription(clazz, methodName);
039        return Request.aClass(clazz).filterWith(method);
040    }
041
042    /**
043     * Create a <code>Request</code> that, when processed, will run all the tests
044     * in a class. The odd name is necessary because <code>class</code> is a reserved word.
045     *
046     * @param clazz the class containing the tests
047     * @return a <code>Request</code> that will cause all tests in the class to be run
048     */
049    public static Request aClass(Class<?> clazz) {
050        return new ClassRequest(clazz);
051    }
052
053    /**
054     * Create a <code>Request</code> that, when processed, will run all the tests
055     * in a class. If the class has a suite() method, it will be ignored.
056     *
057     * @param clazz the class containing the tests
058     * @return a <code>Request</code> that will cause all tests in the class to be run
059     */
060    public static Request classWithoutSuiteMethod(Class<?> clazz) {
061        return new ClassRequest(clazz, false);
062    }
063
064    /**
065     * Create a <code>Request</code> that, when processed, will run all the tests
066     * in a set of classes.
067     *
068     * @param computer Helps construct Runners from classes
069     * @param classes the classes containing the tests
070     * @return a <code>Request</code> that will cause all tests in the classes to be run
071     */
072    public static Request classes(Computer computer, Class<?>... classes) {
073        try {
074            AllDefaultPossibilitiesBuilder builder = new AllDefaultPossibilitiesBuilder(true);
075            Runner suite = computer.getSuite(builder, classes);
076            return runner(suite);
077        } catch (InitializationError e) {
078            throw new RuntimeException(
079                    "Bug in saff's brain: Suite constructor, called as above, should always complete");
080        }
081    }
082
083    /**
084     * Create a <code>Request</code> that, when processed, will run all the tests
085     * in a set of classes with the default <code>Computer</code>.
086     *
087     * @param classes the classes containing the tests
088     * @return a <code>Request</code> that will cause all tests in the classes to be run
089     */
090    public static Request classes(Class<?>... classes) {
091        return classes(JUnitCore.defaultComputer(), classes);
092    }
093
094
095    /**
096     * Not used within JUnit.  Clients should simply instantiate ErrorReportingRunner themselves
097     */
098    @Deprecated
099    public static Request errorReport(Class<?> klass, Throwable cause) {
100        return runner(new ErrorReportingRunner(klass, cause));
101    }
102
103    /**
104     * @param runner the runner to return
105     * @return a <code>Request</code> that will run the given runner when invoked
106     */
107    public static Request runner(final Runner runner) {
108        return new Request() {
109            @Override
110            public Runner getRunner() {
111                return runner;
112            }
113        };
114    }
115
116    /**
117     * Returns a {@link Runner} for this Request
118     *
119     * @return corresponding {@link Runner} for this Request
120     */
121    public abstract Runner getRunner();
122
123    /**
124     * Returns a Request that only contains those tests that should run when
125     * <code>filter</code> is applied
126     *
127     * @param filter The {@link Filter} to apply to this Request
128     * @return the filtered Request
129     */
130    public Request filterWith(Filter filter) {
131        return new FilterRequest(this, filter);
132    }
133
134    /**
135     * Returns a Request that only runs contains tests whose {@link Description}
136     * equals <code>desiredDescription</code>
137     *
138     * @param desiredDescription {@link Description} of those tests that should be run
139     * @return the filtered Request
140     */
141    public Request filterWith(final Description desiredDescription) {
142        return filterWith(Filter.matchMethodDescription(desiredDescription));
143    }
144
145    /**
146     * Returns a Request whose Tests can be run in a certain order, defined by
147     * <code>comparator</code>
148     *
149     * For example, here is code to run a test suite in alphabetical order:
150     *
151     * <pre>
152     * private static Comparator<Description> forward() {
153     * return new Comparator<Description>() {
154     * public int compare(Description o1, Description o2) {
155     * return o1.getDisplayName().compareTo(o2.getDisplayName());
156     * }
157     * };
158     * }
159     *
160     * public static main() {
161     * new JUnitCore().run(Request.aClass(AllTests.class).sortWith(forward()));
162     * }
163     * </pre>
164     *
165     * @param comparator definition of the order of the tests in this Request
166     * @return a Request with ordered Tests
167     */
168    public Request sortWith(Comparator<Description> comparator) {
169        return new SortingRequest(this, comparator);
170    }
171}