"Welcome To Ashok IT"				
			                    "Spring Boot and MicroServices"
                                             Topic : Junit
                                             Date  : 19/01/2025
                                               (Session - 106)                               
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JUnit
======
* Unit testing framework which helps to test piece of code written project.
* Developer level testing framework.

JUnit 5
=======
JUnit 5 is a popular framework for writing and running tests in Java. It is the next generation of JUnit, built to take advantage of Java 8+ features, and consists of three main modules:

JUnit Platform
===============
* Acts as a foundation for launching testing frameworks on the JVM.
* Provides a TestEngine API for developing custom testing frameworks.
* Enables running tests from JUnit 5 and other test engines like Spock or Cucumber.

JUnit Jupiter
=============
* The main module for writing tests in JUnit 5.
* Introduces new annotations and programming models.
* Provides better support for parameterized tests, extensions, and more flexible lifecycle hooks.

JUnit Vintage
=============
* Provides backward compatibility for running JUnit 3 and JUnit 4 tests on the JUnit Platform.
* Useful when migrating existing projects to JUnit 5.

Annotations
============
JUnit 5 introduces new annotations that simplify testing:
1.@Test: Marks a method as a test method.
2.@BeforeEach and @AfterEach: Run before/after each test method.
3.@BeforeAll and @AfterAll: Run once before/after all test methods (must be static).
4.@DisplayName: Customizes test method names for better readability.
5.@Disabled: Disables a test or class.
6.@Nested: Creates nested test classes for better organization.
7.@Tag: Groups tests to control which are executed.

Assertions
==========
* assertEquals(expected, actual), assertTrue(condition), assertNotNull(object), etc.
* Support for grouped and dependent assertions using assertAll.

Parameterized Tests
===================
* Annotations like @ParameterizedTest, @ValueSource, @CsvSource, and @MethodSource allow you to run a test with multiple   inputs.

Example
=======
import org.junit.jupiter.api.*;

import static org.junit.jupiter.api.Assertions.*;

class CalculatorTest {

    private Calculator calculator;

    @BeforeEach
    void setUp() {
        calculator = new Calculator();
    }

    @Test
    @DisplayName("Addition works correctly")
    void testAddition() {
        assertEquals(5, calculator.add(2, 3), "2 + 3 should equal 5");
    }

    @Test
    @Disabled("Not implemented yet")
    void testSubtraction() {
        // Test case to be implemented
    }

    @ParameterizedTest
    @ValueSource(ints = {2, 3, 5, 7, 11})
    void testIsPrime(int number) {
        assertTrue(calculator.isPrime(number), number + " should be prime");
    }

    @AfterEach
    void tearDown() {
        calculator = null;
    }
}

Junit Workshop
==============
https://www.youtube.com/watch?v=3FutI2_Tix8
https://www.youtube.com/watch?v=UhByIkYqHcg       (01:25- Mockito)
https://www.youtube.com/watch?v=xL4OlQ_W3Ek
https://github.com/maheshashokit/JUnit_Workshop_Apps