JavaCheck: Property-based testing for JUnit 5

Java library for property-based testing, inpired by Scalacheck.

Quick start

public class SampleTest {

    @Check
    public void absolute_value_should_not_be_negative(int a) {
        assertThat(Math.abs(a)).isGreaterThanOrEqualTo(0);
    }
}

This test method will be executed several times with various values of a. This test method will fail, as Integer.MIN_VALUE as no matching positive value.

This is exactly the kind of thing JavaCheck will demonstrate, by injecting both specific values and random values.

Extension

Specific Generator

Specific Generators can be declared using the @Generated annotation :

@Check
public void absolute_value_should_not_be_negative(@Generated(IntGenerator.class) int a) {
    assertThat(Math.abs(a)).isGreaterThanOrEqualTo(0);
}

Registering Generator

Generators can be registered using the java ServiceLoader mechanism.

Add you custom-made Generator in the file classpath:META-INF/services/com.github.ledoyen.javacheck.ListGenerator to make in available for all @Check marked test method.