TDD in Java using JUnit Theories

FeatureTest.java

@DataPoints
public static String[] usernames() {
    return new String[] {
        "user1", "user2", "user3", "user4", "user5", "", null
    };
}

@Theory
public void shouldDenyAccessToUsersWhenExceptionsAreUnspecified(String username) {
    FeatureFilter featureFilter = FeatureFilter
        .describeFeature()
        .addFeatureRef("myFeature",
                       thatIsAvailable()
                       .atEndpoint("/myEndpoint")
                       .andDisable());

    assumeThat("Username should not be null nor empty", username, not(isEmptyOrNullString()));
    assertThat(featureFilter.isAllowed("/myEndpoint", username, "myFeature"), is(false));
}

@Theory
public void shouldAllowAccessToUserWhenExceptionIsSpecified(String username) {
    FeatureFilter featureFilter = FeatureFilter
        .describeFeature()
        .addFeatureRef("myFeature",
                       thatIsAvailable()
                       .atEndpoint("/myEndpoint")
                       .andDisable()
                       .exceptForUser(username));

    assumeThat("Username should not be null nor empty", username, not(isEmptyOrNullString()));
    assertThat(featureFilter.isAllowed("/myEndpoint", username, "myFeature"), is(true));
}

@Theory
public void shouldDisallowAccessToInvalidUserWhenExceptionIsSpecified(String validUser, String invalidUser) {
    FeatureFilter featureFilter = FeatureFilter
        .describeFeature()
        .addFeatureRef("myFeature",
                       thatIsAvailable()
                       .atEndpoint("/myEndpoint")
                       .andDisable()
                       .exceptForUser(validUser));

    assumeThat("Username should not be null nor empty", validUser, not(isEmptyOrNullString()));
    assumeThat("Username should not be null nor empty", invalidUser, not(isEmptyOrNullString()));
    assumeThat("Users should be different", validUser, not(equalTo(invalidUser)));
    assertThat(featureFilter.isAllowed("/myEndpoint", invalidUser, "myFeature"), is(false));
}