Why fail () call compiles in java class using JUnit

Question

It seems that it should not compile and run, since Object does not have a fail() method. Is something scared going on during compilation? (I am using NetBeans):

 import static org.junit.Assert.*; import org.junit.Test; public class Test { @Test public void hello() { fail(); } } 

Hello,

Guido

Answer 1

Your import static line imports all the static members of the Assert class into the static namespace of your compilation unit. The fail() call refers to Assert.fail() .

The confusion you face regarding the definition of fail() , which is why I usually do not recommend using import static . In my own code, I usually import the class and use it to call static methods:

 import org.junit.Assert; import org.junit.Test; public class Test { @Test public void hello() { Assert.fail(); } } 

Much more readable.

However, as JB Nizet points out , it is a fairly common practice to use import static for JUnit statements; when you write and read enough JUnit tests, knowing where the approval methods come from will become second nature.

Answer 2

This is completely correct and it will be launched and compiled - I already checked with eclipse. The reason is static import:

 import static org.junit.Assert.*; 

which adds all static fields or methods from the org.junit.Assert class, so it includes the fail () method.

However, a problem may occur that the name of your test class matches the name of the annotation

 @Test 

therefore, it will generate an error:

Import error org.junit.Test in conflict with a type defined in the same file

Answer 3

This error occurs because the name of your name and the name of the annotation are the same (Test). Change your class name to "Test1" or something other than Test.