### Question:
ClientFunction extends ClientOperator<ClientFunction> { @Override public String toString() { final String functionNameString = (functionName != null) ? functionName : ClientExpressions.MISSING_REPRESENTATION; return functionNameString + "(" + operandsToString(getOperands(), ", ") + ")"; } 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 toString_ParenSet_WithoutOperands() { ClientFunction instance = createFullyConfiguredInstance(); assertEquals(TEST_FUNCTION_NAME + "()", instance.toString()); }
@Test public void toString_ParenSet_WithSomeSingleOperand() { ClientFunction instance = createFullyConfiguredInstance(); instance.addOperand(TEST_CLIENT_EXPRESSION); assertEquals(TEST_FUNCTION_NAME + "(" + TEST_INTEGER_VALUE + ")", instance.toString()); }
@Test public void toString_ParenSet_WithSomeMultipleOperands() { ClientFunction instance = createFullyConfiguredInstance(); instance.addOperand(TEST_CLIENT_EXPRESSION); instance.addOperand(TEST_CLIENT_EXPRESSION); assertEquals(TEST_FUNCTION_NAME + "(" + TEST_INTEGER_VALUE + ", " + TEST_INTEGER_VALUE + ")", instance.toString()); }
@Test public void toString_ParenUnSet_WithoutOperands() { ClientFunction instance = new ClientFunction(TEST_FUNCTION_NAME); assertEquals(TEST_FUNCTION_NAME + "()", instance.toString()); }
@Test public void toString_ParenUnSet_WithSomeSingleOperand() { ClientFunction instance = new ClientFunction(TEST_FUNCTION_NAME); instance.addOperand(TEST_CLIENT_EXPRESSION); assertEquals(TEST_FUNCTION_NAME + "(" + TEST_INTEGER_VALUE + ")", instance.toString()); }
@Test public void toString_ParenUnSet_WithSomeMultipleOperands() { ClientFunction instance = new ClientFunction(TEST_FUNCTION_NAME); instance.addOperand(TEST_CLIENT_EXPRESSION); instance.addOperand(TEST_CLIENT_EXPRESSION); assertEquals(TEST_FUNCTION_NAME + "(" + TEST_INTEGER_VALUE + ", " + TEST_INTEGER_VALUE + ")", instance.toString()); }