JUnit 4 to 5 recipe for JUnit4 Parameterized Tests

[pway99]

Discovered while testing Boot2Junit4to5Migration on spring-batch

create a new recipe for converting JUnit4 Parameterized tests

spring-batch parameterized AlmostStatefulChunkRetryTests

[pway99]

Recipe for @ParameterizedTest with @MethodSource

1. Remove `@RunWith(Parameterized.class)`
2. Replace `@Test` with `@ParameterizedTest` having arguments from `@Parameters` method
3. Add `@MethodSource(...)` with argument equal to `@Parameters` method name to each `@ParameterizedTest`
4. Remove @Parameters annotation
5. Change constructor to an initialization method having a void return type.
6. For each `@ParameterizedTest` Insert statement to Invoke initialization method with test parameters
7. Remove imports
	org.junit.Test;
	org.junit.runner.RunWith;
	org.junit.runners.Parameterized;
	org.junit.runners.Parameterized.Parameters;
8. Add imports
	org.junit.jupiter.params.ParameterizedTest;
	org.junit.jupiter.params.provider.MethodSource;


Before:

@RunWith(Parameterized.class)
public class VetTests {

    private String firstName;
    private String lastName;
    private Integer id;

    public VetTests(String firstName, String lastName, Integer id) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.id = id;
    }

    @Test
    public void testSerialization() {
        Vet vet = new Vet();
        vet.setFirstName(firstName);
        vet.setLastName(lastName);
        vet.setId(id);
        Vet other = (Vet) SerializationUtils
                .deserialize(SerializationUtils.serialize(vet));
        assertEquals(vet.getFirstName(), other.getFirstName());
        assertEquals(vet.getLastName(), other.getLastName());
        assertEquals(vet.getId(), other.getId());
    }

    @Parameters(name="{index}: {0} {1} - {2}")
    public static List<Object[]> parameters() {
        return Arrays.asList(new Object[] {
            new Object[] { "Otis "TheDog", 124 },
            new Object[] { "Garfield", "TheBoss", 126 });
    }

}


After:

public class VetTests {

    private String firstName;
    private String lastName;
    private Integer id;

    public void initVetTests(String firstName, String lastName, Integer id) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.id = id;
    }

    @ParameterizedTest(name = "{index}: {0} {1} {2}")
    @MethodSource("parameters")
    public void testSerialization(String firstName, String lastName, Integer id) {
        initVetTests(firstName, lastName, id);
        Vet vet = new Vet();
        vet.setFirstName(firstName);
        vet.setLastName(lastName);
        vet.setId(id);
        Vet other = (Vet) SerializationUtils
                .deserialize(SerializationUtils.serialize(vet));
        assertEquals(vet.getFirstName(), other.getFirstName());
        assertEquals(vet.getLastName(), other.getLastName());
        assertEquals(vet.getId(), other.getId());
    }

    public static List<Object[]> parameters() {
        return Arrays.asList(new Object[] {
            new Object[] { "Otis "TheDog", 124 },
            new Object[] { "Garfield", "TheBoss", 126 });
    }
}

Reference info

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

  

  Parameterized Test Samples
• 
https://github.com/spring-projects/spring-retry/blob/master/src/test/java/org/springframework/retry/policy/RetryContextSerializationTests.java
• https://github.com/spring-projects/spring-batch/blob/master/spring-batch-core/src/test/java/org/springframework/batch/core/configuration/xml/StepNameTests.java
• https://github.com/antlr/antlr4/blob/master/runtime-testsuite/test/org/antlr/v4/test/runtime/go/TestPerformance.java#L17
• https://github.com/estatio/estatio/blob/master/estatioapp/app/src/test/java/org/estatio/module/capex/platform/pdfmanipulator/ExtractSpecTest_pagesFor.java#L13