### Question:
BasicRateMeasurement extends BasicMeasurement implements RateMeasurement { @Override public String toString() { return (d_rate == null ? "N/A" : d_rate.toString()) + " / " + (getSampleSize() == null ? "N/A" : getSampleSize().toString()); } BasicRateMeasurement();  BasicRateMeasurement(Integer rate, Integer total); String getLabel(); @Override String toString(); void setRate(Integer rate); Integer getRate(); boolean isOfType(VariableType type); @Override boolean equals(Object o); @Override int hashCode(); @Override BasicMeasurement clone(); @Override boolean isComplete();  }### Answer:
@Test public void testToString() { assertEquals("67 / 101", d_measurement.toString()); d_measurement.setRate(null); assertEquals("N/A / 101", d_measurement.toString()); d_measurement.setRate(10); d_measurement.setSampleSize(null); assertEquals("10 / N/A", d_measurement.toString()); }