### Question:
FunctionRegistryHolder { public boolean containsJar(String jarName) { try (AutoCloseableLock lock = readLock.open()) { return jars.containsKey(jarName); } } FunctionRegistryHolder(); long getVersion(); void addJars(Map<String, List<FunctionHolder>> newJars, long version); void removeJar(String jarName); List<String> getAllJarNames(); List<String> getFunctionNamesByJar(String jarName); ListMultimap<String, DrillFuncHolder> getAllFunctionsWithHolders(AtomicLong version); ListMultimap<String, DrillFuncHolder> getAllFunctionsWithHolders(); ListMultimap<String, String> getAllFunctionsWithSignatures(); List<DrillFuncHolder> getHoldersByFunctionName(String functionName, AtomicLong version); List<DrillFuncHolder> getHoldersByFunctionName(String functionName); boolean containsJar(String jarName); int functionsSize(); String getJarNameByFunctionSignature(String functionName, String functionSignature);  }### Answer:
@Test public void testContainsJar() { assertTrue("Jar should be present in registry holder", registryHolder.containsJar(built_in)); assertFalse("Jar should be absent in registry holder", registryHolder.containsJar("unknown.jar")); }