### Question:
SpeedCalculator { public String instantSpeed() { return getSpeedWithSIAndFlush(); }  synchronized void reset(); synchronized void downloading(long increaseBytes); synchronized void flush(); long getInstantBytesPerSecondAndFlush(); synchronized long getBytesPerSecondAndFlush(); synchronized long getBytesPerSecondFromBegin(); synchronized void endTask(); String instantSpeed(); String speed(); String lastSpeed(); synchronized long getInstantSpeedDurationMillis(); String getSpeedWithBinaryAndFlush(); String getSpeedWithSIAndFlush(); String averageSpeed(); String speedFromBegin();  }### Answer:
@Test public void instantSpeed() { doReturn("1").when(calculator).getSpeedWithSIAndFlush(); assertThat(calculator.instantSpeed()).isEqualTo("1"); }