@Subject
    def comparer = ExhaustiveLinesSearcher.useLcsDiff()

    // region: assertLinesContainedIn
    def "neither expected or actual lines can be empty"() {
        when:
        comparer.assertLinesContainedIn([], ["a"])
        then:
        thrown(AssertionError)

        when:
        comparer.assertLinesContainedIn(["a"], [])
        then:
        thrown(AssertionError)
    }

        List<String> actualLines = Arrays.asList(getOutput().split("\\R"));
        List<String> expectedLines = Arrays.asList(expectedText.split("\\R"));
        searcher.assertLinesContainedIn(expectedLines, actualLines);
        return this;
    }

    /**
     * Specifies different formats for reporting a failure of {@link #assertOutputContains(String)}.
     */

        List<String> actualLines = Arrays.asList(getOutput().split("\\R"));
        List<String> expectedLines = Arrays.asList(expectedText.split("\\R"));
        searcher.assertLinesContainedIn(expectedLines, actualLines);
        return this;
    }

    /**
     * Specifies different formats for reporting a failure of {@link #assertOutputContains(String)}.
     */

     *
     * @return searcher that uses a unified diff output
     */
    public static ExhaustiveLinesSearcher useLcsDiff() {
        return new ExhaustiveLinesSearcher(false);
    }

    public void assertLinesContainedIn(List<String> expectedLines, List<String> actualLines) throws LineSearchFailures.AbstractLineListComparisonFailure {
        assert !expectedLines.isEmpty() : "there must be expected text";