@Test
public void simple() {

    assertEquals(Collections.singletonList(
            new NumberElement("10")),
            NumberParser.parse("10"));
    assertEquals(Collections.singletonList(
            new NumberElement("10")),
            NumberParser.parse("  10   "));
    assertEquals(Collections.singletonList(
            new NumberElement("10a")),
            NumberParser.parse("10a"));
    assertEquals(Collections.singletonList(
            new NumberElement("foo")),
            NumberParser.parse("foo"));
}