### Question:
BigIntegers { public static Mapper<Float, BigInteger> fromFloatToBigInteger() { return new Mapper<Float, BigInteger>() { @Override public BigInteger map(Float input) { return new BigInteger(((Integer) input.intValue()).toString()); } }; }  static Mapper<String, BigInteger> fromStringToBigInteger(); static Mapper<Integer, BigInteger> fromIntegerToBigInteger(); static Mapper<Long, BigInteger> fromLongToBigInteger(); static Mapper<Float, BigInteger> fromFloatToBigInteger(); static Mapper<Double, BigInteger> fromDoubleToBigInteger(); static Mapper<BigDecimal, BigInteger> fromBigDecimalToBigInteger();  }### Answer:
@Test public void returnsMapperFromFloatToBigInteger() { assertThat(fromFloatToBigInteger().map(1234.56F), is(new BigInteger("1234"))); }
@Test(expected = NullPointerException.class) public void throwsNullPointerExceptionWhenMapperFromFloatToBigIntegerPassedNull() { fromFloatToBigInteger().map(null); }