Unit testing

Introduction to Unit Testing

Author : Pooya Sagharchi HaJanuary 27, 2015

Agenda

● What is Unit Testing ?

● Why should we Unit Test?

● Isolate units for testing

● UnitTest++ framework

● HippoMocks framework

Unit Testing● The smallest testable parts of an application, are

called units

● Unit Test is a method in which a programmer

tests individual units

● execute a program using artificial data

Unit Testing

input

Main Class Testing Class

output

True or False

Isolate Unit Testing● it goal is to isolate each part of the program and show that the

individual parts are correct

Class 1

Class 2

Class 3

Class 4

Class 3

Testing Class

input

output

True or False

Why Unit Testing?

● helps to find the problems early in the software

development

● Can be used to validate that the code

functionality still works after code change

UnitTest++

● lightweight

● Simplicity

● Portability ( platform Linux, Mac and windows )

● Speed

Getting started:1. Create a header file on UnitTests folder2. Include UnitTest++.h and TestReporterStdout.h3. Write your test in TEST body4. Compile it

UnitTest++

UnitTest++For example : #include "UnitTest++.h"#include "TestReportsStdout.h"TEST(ChechSumTest){

int sum =0;for(int i=0; i < 5; ++i)

sum += i;CHECK_EQUAL(10, sum);}

UnitTest++● Test macro

Define : simply put the following code in a .cpp file of your choice.

Syntax : TEST(YourTestName) { }

UnitTest++● Suit macro

Define : A suite serves as a namespace for test names, so that the same test name can be used in two different contexts.

Syntax : SU ITE(YourSuiteName) { TEST(YourTestName) { }

TEST(YourOtherTestName) { } }

UnitTest++● Check macro

Define : It will fail if the boolean expression evaluates to false and conversely.

Syntax : TEST(YourTestName) {

Check(value); }

UnitTest++● Check Equal macro

Define : It will compare expected argument and actual argument.

Syntax : TEST(YourTestName) {

Check_EQUAL(expected, actual); }

UnitTest++● Check Close macro

Define : It is used for floating-point comparison.

Syntax : TEST(YourTestName) {

Check_CLOSE(expected, actual, tolerance); }

UnitTest++● Array macroThere is a set of check macros for array comparison as well.

Syntax : TEST(YourTestName) {

Check_Array_EQUAL(expected, actual, count);Check_Array_CLOSE(expected, actual, tolerance);Check_Array2D_EQUAL(expected, actual, row, columns, tolerance);

}

UnitTest++

● Exception check macros

Define : which asserts that its enclosed expression throws the specified type.

Syntax : TEST(YourTestName) {

Check_THROW(expression, ExpectedExpectionType); }

HippoMocksGetting started:1. Create a header file on UnitTests folder2. Include UnitTest++.h and TestReporterStdout.h

and hippmocks.h3. Write your test in TEST body4. Compile it

HippoMocks● MockRepository class

Define : Create a MockRepository on the stack.

Syntax : TEST(YourTestName) {

MockRepository mocks; }

HippoMocks● Interface Mock

Define : Used to create an instance of a class that implements a given interface.

Syntax : TEST(YourTestName) {

MockRepository mocks;ClassName *classnameMock = mocks.Mock<ClassName>(); }

HippoMocks● Expected Call

Define : Indicates that the given method on the mock will be called. If the method is not called before the Repository destructs, a runtime error is generated.

Syntax : TEST(YourTestName) {

MockRepository mocks;ClassName *classnameMock = mocks.Mock<ClassName>();mock.ExpectCall(obj, func); }

HippoMocks● Expected Call

Define : AutoExpect can be called prior to calls to ExpectCall but the order of your program increase.

Syntax : TEST(YourTestName) {

MockRepository mocks;ClassName *classnameMock = mocks.Mock<ClassName>();mocks.autoExpect = false or true; }

HippoMocks● On Call

Define : Similar to ExpectCall, except that it's okay if the method doesn't get called.

Syntax : TEST(YourTestName) {

MockRepository mocks;ClassName *classnameMock = mocks.Mock<ClassName>();mock.OnCall(obj, func); }

HippoMocks● Never Call

Define : Similar to ExpectCall, except that it sets up expectation that the method will never be called.

Syntax : TEST(YourTestName) {

MockRepository mocks;ClassName *classnameMock = mocks.Mock<ClassName>();mock.NeverCall(obj, func); }

HippoMocks● TCall class

Define : This class is not instantiated directly. It's returned by MockRepository::ExpectCall The TCall class can be used to further refine the expectations of the method call.

HippoMocks● With

Define : When used, indicates what parameters expected to be passed in.

Syntax : TEST(YourTestName) {

MockRepository mocks;ClassName *classnameMock = mocks.Mock<ClassName>();mock.ExpectCall(obj, func).With(value); }

HippoMocks● Return

Define : When used, indicates what value the method will return.

Syntax : TEST(YourTestName) {

MockRepository mocks;ClassName *classnameMock = mocks.Mock<ClassName>();mock.ExpectCall(obj, func).Return(obj); }

HippoMocks● Throw

Define : When used, indicates that the method must throw an exception.

Syntax : TEST(YourTestName) {

MockRepository mocks;ClassName *classnameMock = mocks.Mock<ClassName>();mock.ExpectCall(obj, func).Throw(exception); }

HippoMocks● Do

Define : When used, indicates what the method will do by passing in a function pointer.

Syntax : TEST(YourTestName) {

MockRepository mocks;ClassName *classnameMock = mocks.Mock<ClassName>();mock.ExpectCall(obj, func).Do(function); }