org.itsallcode.junit.sysextensions.AssertExit Maven / Gradle / Ivy

Go to download
package org.itsallcode.junit.sysextensions;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.fail;

import java.util.logging.Logger;

import org.itsallcode.junit.sysextensions.security.ExitTrapException;

/**
 * Utility class to assert that a lambda expression calls
 * {@link System#exit(int)}.
 */
public final class AssertExit
{
    private static final Logger LOGGER = Logger.getLogger(AssertExit.class.getName());
    private AssertExit()
    {
        // prevent instantiation
    }

    /**
     * Assert that the code in the given lambda called {@link System#exit(int)}.
     *
     * @param runnable
     *            lambda expression that is expected to call
     *            {@link System#exit(int)}
     */
    public static void assertExit(final Runnable runnable)
    {
        try
        {
            runnable.run();
        }
        catch (final ExitTrapException exception)
        {
            LOGGER.fine(
                    () -> "Caught ExitTrapException " + exception + " with exit status " + exception.getExitStatus());
            return;
        }
        failMissingExit();
    }

    private static void failMissingExit()
    {
        fail("Lambda did not cause a system exit as expected.");
    }

    /**
     * Assert that the code in the given lambda called {@link System#exit(int)}
     * with a the expected exit code.
     *
     * @param expectedExitCode
     *            expected exit status code
     * @param runnable
     *            lambda expression that is expected to call
     *            {@link System#exit(int)}
     */
    public static void assertExitWithStatus(final int expectedExitCode, final Runnable runnable)
    {
        try
        {
            runnable.run();
        }
        catch (final ExitTrapException exception)
        {
            LOGGER.fine(
                    () -> "Caught ExitTrapException " + exception + " with exit status " + exception.getExitStatus());
            assertEquals(expectedExitCode, exception.getExitStatus(), "Expected exit status code");
            return;
        }
        failMissingExit();
    }
}