Gain insights into JUnit 5, explore its advantages over JUnit 4, and delve into its features like assertions, parameterized tests, dependency injection, and test execution order. Discover hands-on projects to cement your skills.

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JUnit 5 is a standard framework for unit testing in Java. Released in 2017, JUnit 5 is a major improvement over JUnit 4 and supports a lot of new methods. Many projects have migrated from JUnit 4 to JUnit 5. JUnit 5 is also the default test framework for new projects. JUnit 5 is composed of three sub-projects: JUnit Platform, JUnit Jupiter, and JUnit Vintage. Details of these sub-projects are discussed in the course.

This course first discusses the advantages of JUnit 5 over the previous versions and then jumps directly into tests. The course includes discussion on assertions, assumptions, tagging and filtering, nested tests, dependency injection, repeated tests, parameterized tests, dynamic tests, test instance lifecycle, extension model, JUnit 4 migration, JUnit platform, and test execution order. 

By the end of this course, you’ll be deeply familiar with unit testing in JUnit 5. There’s also a little project for you at the end to put your newly acquired skills to the test.

All About JUnit5

# What are assertions?
**Assertions** verify that expected conditions are met. JUnit 5 adds more assertion methods. All JUnit 5 assertions are static methods of the class `org.junit.jupiter.Assertions`. Some assertions already exist in JUnit 4. These assertions have been updated in JUnit 5. Each assertion has different overloaded methods to accept different parameters.



# The `assertTrue()` method
The `assertTrue()` method asserts that the given condition is `true`.
- If the given condition is `true`, the test case passes.
- If the given condition is `false`, the test case fails.


# Examples of `assertTrue()`
It has the following overloaded methods:

public static void assertTrue(boolean condition)
  
public static void assertTrue(boolean condition, String message)

public static void assertTrue(boolean condition, Supplier<String> messageSupplier)

public static void assertTrue(BooleanSupplier booleanSupplier)
  
public static void assertTrue(BooleanSupplier booleanSupplier, String message)
  
public static void assertTrue(BooleanSupplier booleanSupplier, Supplier<String> messageSupplier)


* The `assertTrue(boolean condition)` method is the simplest form, which only accepts a single boolean parameter. Examples of this function can be seen in **lines 5–9** and **11–15** in the code below. Note that the function `testAssertTrueWithTrueCondition()` passes because it’s passed a `true` value, whereas the function `testAssertTrueWithFalseCondition()` doesn’t pass because `false` is passed.
 
*  For the `assertTrue(boolean condition, String message)` method, when the condition isn’t met, it fails with the given message. Examples of the function can be seen in **lines 17–22** and **24–29** in the code below. Note that the function `testAssertTrueWithFalseConditionAndMessage()`, doesn’t pass as it is it’s passed a `false` value, whereas the function `testAssertTrueWithTrueConditionAndMessage()` does pass because `true` is passed.






Learn about the assertTrue() and assertFalse() methods in JUnit 5.

Getting Started

Writing Basic Tests

Annotations, Tagging, and Filtering

Nested tests in JUnit 5

Dependency Injections

Parameterized and Dynamic Tests

Test Instance Lifecycle in JUnit 5

Extension Model

JUnit Platform

Test Execution Order

Conclusion

Library Management System

Assertions: assertTrue() and assertFalse()

What are assertions?

The `assertTrue()` method

Examples of `assertTrue()`

Library Management System

Assertions: assertTrue() and assertFalse()

What are assertions?

The assertTrue() method

Examples of assertTrue()

The `assertTrue()` method

Examples of `assertTrue()`