### Question:
NMEAMappers { public static final UnaryOperator<NMEASample> driftAngleMap() { return new DriftAngleMap(); }  static final UnaryOperator<NMEASample> driftAngleMap();  }### Answer:
@Test public void testDriftAngleMap1() { NMEAStream.Builder builder = new NMEAStream.Builder(); builder.addSample() .setProperty("trackMadeGood", 350) .setProperty("trueHeading", 340); NMEASample sample = builder.build().map(NMEAMappers.driftAngleMap()).findFirst().get(); assertEquals(10, sample.getProperty("driftAngle"), Epsilon); }
@Test public void testDriftAngleMap2() { NMEAStream.Builder builder = new NMEAStream.Builder(); builder.addSample() .setProperty("trueHeading", 340); NMEASample sample = builder.build().map(NMEAMappers.driftAngleMap()).findFirst().get(); assertEquals(0, sample.getProperty("driftAngle"), Epsilon); }