### Question:
CaliperConfig { public ImmutableSet<String> getConfiguredInstruments() { ImmutableSet.Builder<String> resultBuilder = ImmutableSet.builder(); for (String key : subgroupMap(properties, "instrument").keySet()) { Matcher matcher = INSTRUMENT_CLASS_PATTERN.matcher(key); if (matcher.matches()) { resultBuilder.add(matcher.group(1)); } } return resultBuilder.build(); } @VisibleForTesting  CaliperConfig(ImmutableMap<String, String> properties); ImmutableMap<String, String> properties(); VmConfig getDefaultVmConfig(); VmConfig getVmConfig(String name); ImmutableSet<String> getConfiguredInstruments(); InstrumentConfig getInstrumentConfig(String name); ImmutableSet<Class<? extends ResultProcessor>> getConfiguredResultProcessors(); ResultProcessorConfig getResultProcessorConfig(
      Class<? extends ResultProcessor> resultProcessorClass); @Override String toString();  }### Answer:
@Test public void getConfiguredInstruments() throws Exception { CaliperConfig configuration = new CaliperConfig(ImmutableMap.of( "instrument.test.class", "test.ClassName", "instrument.test2.class", "test.ClassName", "instrument.test3.options.a", "1", "instrument.test4.class", "test.ClassName", "instrument.test4.options.b", "excited b b excited")); assertEquals(ImmutableSet.of("test", "test2", "test4"), configuration.getConfiguredInstruments()); }