### Question:
Longs { public static Mapper<Float, Long> fromFloatToLong() { return new Mapper<Float, Long>() { @Override public Long map(Float input) { return input.longValue(); } }; } private  Longs(); static Mapper<String, Long> fromStringToLong(); static Mapper<Integer, Long> fromIntegerToLong(); static Mapper<BigInteger, Long> fromBigIntegerToLong(); static Mapper<Float, Long> fromFloatToLong(); static Mapper<Double, Long> fromDoubleToLong(); static Mapper<BigDecimal, Long> fromBigDecimalToLong(); static Long toLongOrNull(String value); static Long toLongOrNull(Integer value); static Long toLongOrNull(BigInteger value); static Long toLongOrNull(Float value); static Long toLongOrNull(Double value); static Long toLongOrNull(BigDecimal value); static Mapper<String, Option<Long>> fromStringToPossibleLong();  }### Answer:
@Test public void returnsMapperFromFloatToLong() { assertThat(fromFloatToLong().map(1234.56F), is(1234L)); }
@Test(expected = NullPointerException.class) public void throwsNullPointerExceptionWhenMapperFromFloatToLongPassedNull() { fromFloatToLong().map(null); }