### Question:
ClientFunction extends ClientOperator<ClientFunction> { public String getFunctionName() { return functionName; } ClientFunction();  ClientFunction(String functionName, List<ClientExpression> operands);  ClientFunction(ClientFunction source);  ClientFunction(String functionName); String getFunctionName(); ClientFunction setFunctionName(String functionName); ClientFunction addArgument(ClientExpression expr); @Override String toString(); @Override void accept(ClientELVisitor visitor); @Override boolean equals(Object o); @Override int hashCode(); @Override ClientFunction deepClone(); int getPrecedence(); static final String EXPRESSION_ID; }### Answer:
@Test public void instanceCanBeCreatedWithFunctionName() { ClientFunction instance = new ClientFunction(TEST_FUNCTION_NAME); assertEquals(TEST_FUNCTION_NAME, instance.getFunctionName()); assertEquals(ClientOperation.FUNCTION, instance.getOperator()); assertEquals(Collections.emptyList(), instance.getOperands()); }
@Test public void instanceCanBeCreatedByDefaultConstructor() { ClientFunction instance = new ClientFunction(); assertNull(instance.getFunctionName()); assertEquals(Collections.emptyList(), instance.getOperands()); }