google3/third_party/java_src/junit/main/java/org/junit/internal/requests/FilterRequest.java

package org.junit.internal.requests;

import org.junit.internal.runners.ErrorReportingRunner;
import org.junit.runner.Request;
import org.junit.runner.Runner;
import org.junit.runner.manipulation.Filter;
import org.junit.runner.manipulation.NoTestsRemainException;

/**
 * A filtered {@link Request}.
 */
public final class FilterRequest extends Request {
    private final Request request;
    /*
     * We have to use the f prefix, because IntelliJ's JUnit4IdeaTestRunner uses
     * reflection to access this field. See
     * https://github.com/junit-team/junit4/issues/960
     */
    private final Filter fFilter;

    /**
     * Creates a filtered Request
     *
     * @param request a {@link Request} describing your Tests
     * @param filter {@link Filter} to apply to the Tests described in
     * <code>request</code>
     */
    public FilterRequest(Request request, Filter filter) {
        this.request = request;
        this.fFilter = filter;
    }

    @Override
    public Runner getRunner() {
        try {
            Runner runner = request.getRunner();
            fFilter.apply(runner);
            return runner;
        } catch (NoTestsRemainException e) {
            return new ErrorReportingRunner(Filter.class, new Exception(String
                    .format("No tests found matching %s from %s", fFilter
                            .describe(), request.toString())));
        }
    }
}