@Test
public void testExpectHeight_Mismatch() {

    DataFrame df = DataFrame.newFrame("a").foldByRow("a", "b");
    try {
        new DataFrameAsserts(df, "a").expectHeight(3);
        throw new RuntimeException("Must have failed comparision");
    } catch (AssertionError f) {
        assertEquals("Unexpected DataFrame height ==> expected: <3> but was: <2>", f.getMessage());
    }
}