README.md

junit-parameterized-tests

The main goal of this project is to compare parametrized tests in JUnit4 and JUnit5.

Reference: https://github.com/junit-team/junit4/wiki/parameterized-tests
Reference: https://junit.org/junit5/docs/current/user-guide/#writing-tests-parameterized-tests

manual

JUnit 4

• build.gradle

  testCompile group: 'junit', name: 'junit', version: '4.12'
  

• parametrized test

  1. method

     @Test
     public void add() {
         assertEquals(expectedSum, Calculator.add(a, b));
     }    
     

  2. constructor of a test class + fields (matching parameters)

     private int a;
     private int b;
     private int expectedSum;
     
     public CalculatorTest(int a, int b, int expectedSum) {
         this.a = a;
         this.b = b;
         this.expectedSum = expectedSum;
     }    
     

  3. data supplier

     @Parameters(name = "{index}: sum({0} + {1})={2}")
     public static Iterable<Object[]> data() {
         return Arrays.asList(new Object[][] {
                 { 0, 0, 0 }, 
                 { 1, 1, 2 }, 
                 { 2, 1, 3 }, 
                 { 1, 3, 4 }, 
                 { -4, 4, 0 }, 
                 { -5, -5, -10 }, 
                 { -3, 6, 3 }
         });
     }    
     

     where:

     @Parameters(name = "{index}: sum({0} + {1})={2}")
     

     is a label for test cases:

     [0:sum(0+0)=0]
         add[0:sum(0+0)=0]
     [1:sum(1+1)=2]
         add[1:sum(1+1)=2]
     [2:sum(2+1)=3]
         add[2:sum(2+1)=3]
     

Junit 5

• build.gradle

  testCompile group: 'org.junit.jupiter', name: 'junit-jupiter-api', version: '5.2.0'
  testCompile group: 'org.junit.jupiter', name: 'junit-jupiter-params', version: '5.2.0'    
  

• parametrized test

  1. method

     @DisplayName("Test of add method")
     @ParameterizedTest(name = "{index} ==> {0} + {1} = {2}")
     @MethodSource
     void add(int a, int b, int expectedSum) {
         assertEquals(expectedSum, Calculator.add(a, b));
     }    
     

  2. data supplier

     static Stream<Arguments> add() {
             return Stream.of(
                     Arguments.of(0, 0, 0),
                     Arguments.of(1, 1, 2),
                     Arguments.of(2, 1, 3),
                     Arguments.of(1, 3, 4),
                     Arguments.of(-4, 4, 0),
                     Arguments.of(-5, -5, -10),
                     Arguments.of(-3, 6, 3)
             );
         }
     

     Remark: default name for supplier method is same as tested method