### Question:
NIFSSupport implements ITccInstrumentSupport { public String getWavelength() { InstNIFS inst = (InstNIFS) _oe.getInstrument(); NIFSParams.Disperser d = inst.getDisperser(); NIFSParams.Filter f = inst.getFilter(); double wl = inst.getCentralWavelength(); if ((d == null) || (f == null)) { return String.valueOf(InstNIFS.DEF_CENTRAL_WAVELENGTH); } String res = InstNIFS.calcWavelength(d, f, wl); if ((res == null) || "".equals(res)) { return String.valueOf(InstNIFS.DEF_CENTRAL_WAVELENGTH); } return res; } private  NIFSSupport(ObservationEnvironment oe); static ITccInstrumentSupport create(ObservationEnvironment oe); String getWavelength(); String getPositionAngle(); void addGuideDetails(ParamSet p); String getTccConfigInstrument(); String getTccConfigInstrumentOrigin(); String getFixedRotatorConfigName(); String getChopState();  }### Answer:
@Test public void testWavelength() throws Exception { InstNIFS nifs = getInstrument(); nifs.setDisperser(NIFSParams.Disperser.MIRROR); nifs.setFilter(NIFSParams.Filter.JH_FILTER); setInstrument(nifs); assertEquals(NIFSParams.Filter.JH_FILTER.getWavelength(), getWavelength(getSouthResults())); }