JUnit test with dynamic number of tests

Question

In our project I have several JUnit tests that e.g. take every file from a directory and run a test on it. If I implement a testEveryFileInDirectory method in t

Answer 1

Junit 5 Parameterized Tests

JUnit 5 parameterized tests support this by allowing the use of a method as data source:

@ParameterizedTest
@MethodSource("fileProvider")
void testFile(File f) {
    // Your test comes here
}

static Stream fileProvider() {
    return Arrays.asList(new File(".").list()).stream();
}

JUnit 5 DynamicTests

JUnit 5 also supports this through the notion of a DynamicTest, which is to be generated in a @TestFactory, by means of the static method dynamicTest.

import org.junit.jupiter.api.DynamicTest;
import org.junit.jupiter.api.TestFactory;
import static org.junit.jupiter.api.DynamicTest.dynamicTest;

import java.util.stream.Stream;

@TestFactory
public Stream testFiles() {
    return Arrays.asList(new File(".").list())
            .stream()
            .map((file) -> dynamicTest(
                    "Test for file: " + file,
                    () -> { /* Your test comes here */ }));
}

The tests run in your IDE (IntelliJ here) will be displayed like this: