@Test
public void testTestTextWilcoxonRankSum() {

    double p = ForeignKeys.testTextWilcoxonRankSum(
            new ArrayList<>(Arrays.asList("a", "b", "c", "d", "e")),
            new ArrayList<>(Arrays.asList("a", "b", "c", "d", "e"))
    );
    Assert.assertEquals(.5, p, .001);
    p = ForeignKeys.testTextWilcoxonRankSum(
            new ArrayList<>(Arrays.asList("a", "b", "c", "d")),
            new ArrayList<>(Arrays.asList("a", "b", "c", "d", "e"))
    );
    Assert.assertEquals(8.0 / 20.0, p, .001);
    p = ForeignKeys.testTextWilcoxonRankSum(
            new ArrayList<>(Arrays.asList("b", "b", "c", "c")),
            new ArrayList<>(Arrays.asList("a", "b", "c", "d", "e"))
    );
    Assert.assertEquals(8.0 / 20.0, p, .001);
    p = ForeignKeys.testTextWilcoxonRankSum(
            new ArrayList<>(Collections.singletonList("a")),
            new ArrayList<>(Arrays.asList("b", "c", "d", "e"))
    );
    Assert.assertEquals(0.0, p, .001);
    p = ForeignKeys.testTextWilcoxonRankSum(
            new ArrayList<>(Arrays.asList("f", "g")),
            new ArrayList<>(Arrays.asList("b", "c", "d", "e"))
    );
    Assert.assertEquals(1.0, p, .001);
}