### Question:
IntegerOperations implements MathOperations<Integer>, Comparator<Integer> { public Integer keepSignificantFigures( Integer value, int numSigFigs ) { if (numSigFigs < 0) return value; if (numSigFigs == 0) return 0; int currentExp = getExponentInScientificNotation(value); int decimalShift = -currentExp + numSigFigs - 1; return roundUp(value, decimalShift); }  Class<Integer> getOperandClass(); Integer add( Integer value1,
                        Integer value2 ); Integer subtract( Integer value1,
                             Integer value2 ); Integer multiply( Integer value1,
                             Integer value2 ); double divide( Integer value1,
                          Integer value2 ); Integer negate( Integer value ); Integer increment( Integer value ); Integer maximum( Integer value1,
                            Integer value2 ); Integer minimum( Integer value1,
                            Integer value2 ); int compare( Integer value1,
                        Integer value2 ); BigDecimal asBigDecimal( Integer value ); Integer fromBigDecimal( BigDecimal value ); Integer createZeroValue(); Integer create( int value ); Integer create( long value ); Integer create( double value ); double sqrt( Integer value ); Comparator<Integer> getComparator(); Integer random( Integer minimum,
                           Integer maximum,
                           Random rng ); double doubleValue( Integer value ); float floatValue( Integer value ); int intValue( Integer value ); long longValue( Integer value ); short shortValue( Integer value ); int getExponentInScientificNotation( Integer value ); Integer roundUp( Integer value,
                            int decimalShift ); Integer roundDown( Integer value,
                              int decimalShift ); Integer keepSignificantFigures( Integer value,
                                           int numSigFigs );  }### Answer:
@Test public void shouldKeepSignificantFigures() { assertThat(ops.keepSignificantFigures(0, 2), is(0)); assertThat(ops.keepSignificantFigures(1201234, 5), is(1201200)); assertThat(ops.keepSignificantFigures(1201254, 5), is(1201300)); assertThat(ops.keepSignificantFigures(1201234, 4), is(1201000)); assertThat(ops.keepSignificantFigures(1201234, 3), is(1200000)); assertThat(ops.keepSignificantFigures(1201234, 2), is(1200000)); assertThat(ops.keepSignificantFigures(1201234, 1), is(1000000)); assertThat(ops.keepSignificantFigures(-1320, 2), is(-1300)); }