README.md

Test With JUnit 5

To create a simple test

Create a class in the class

create a void method use the @Test

use the basics

assertEquals expected / actual

check is a object is not null assertNotNull

check is a object is null assertNull

for boolean values check is actual is false assertFalse

check is actual is true assertTrue

to Array check is one array is same than another assertArrayEquals( expected , actual ); this check all position same equals and the size is the same

the annotation @BeforeEach is execute before (antes) all test if you has 3 test the method is run 3 times

the annotation @AfterEach is execute after (depois) all test if you has 3 test the method is run 3 times

the methods with @BeforeEach and @AfterEach you can use a parameter TestInfo with a instance o TestInfo you can get the name of method

With the JUnit 4 use @Before and @After but the TestInfo not present TestInfo is only in JUnit 5

You can use the @BeforeAll to connect the database for exemple this method need to be static the method is call frist before than all tests

You can use the @AfterAll to close connect the database for exemple this method need to be static the method is call after before than all tests

In JUnit 5 the word public is not required in test's

the annotation @DisplayName show the message that you put in before run the test

@ParameterizedTest you can use multiple values with this annotation use with the @ValueSource sample @ParameterizedTest @ValueSource(strings= { "ABCD" , "ABC", "AB" } ) void lengthMoreThanZeroParametrize(String string) { assertTrue( string.length() > 0 ); }

//Sample to give name to ParameterizedTest I can change the output of test with @ParameterizedTest( name = "the string {0} length is {1}") //change de out put {0} before ',' and {1} after ',

I can repeat many time with RepeatedTest @RepeatedTest( 3 )

I can try de performace with assertTimeout Use a the aegs : aTime, () -> { }
assertTimeout( Duration.ofSeconds(5), () -> { for (int i = 0; i < 100; i++ ) { System.out.println( i ); } });

I can disable a test @Disabled in JUnit 5 with 4 use @Ignored

If I can not run any Test in a class I use @Disable in the class when I use in classe any test not run

the annotation @Nested I can use to use a nested class when a run a test

JUnit 5 x JUnit 4 != @BeforeAll instead of @BeforeClass @AfterAll instead of @AfterClass @BeforeEach instead of @Before @AfterEach instead of @After @Disable instead of @Ignote @Tag instead of @Category assertThrows instead of expected attibute assertTimeout instead of timeout attibute

New in JUnit 5 @Nested for nested tests @RepeatedTest to execute tests mulpiple times

Best pratices for good unit test 1 Readable Look at the test and you know what is begin tested (I can read the class test and know what the test is do in 15 seconds)

2 Fast what happerns if unit tests take a long time to run? (think abaout what the advantage of unit test is lost 2 hours?)

3 Isolated Fails only when there is an issue whith code! (is not good if they star failing because of an external depedency not avaliable then the fail)

4 Run often What is the use having unit test which are note run frenquently? What happens if you do not commit code often?