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Assertions in Junit 5

 

Junit has more assertion type methods than Junit 4. Several have been added and they work very well together with the lambda expressions in Java 8. All these types of methods are static and come from the org.junit.jupiter.api.Assertions class.

 

The comparison between assertions in Junit 4 and Junit 5 look like this:

 

JUnit 4	JUnit 5
Assert Class The optional message is the first parameter	Assertions Class The optional message is the last parameter The assertThat method has been removed New methods: assertAll and assertThrows

 

The message in assertions is the last parameter of the methods:

 

 

The supplier allows for lazy initialization in case of complex messages. A chunk of code which uses possible assertions looks like this:

 

Tudose, Florin-Catalin Tudose

Java Champion; Java Chapter Lead; Author at Pluralsight and Manning