Then create the test itself:

  • Java

  • Kotlin

Create the src/test/java/org/acme/schooltimetabling/solver/TimetableConstraintProviderTest.java class:

package org.acme.schooltimetabling.solver;

import java.time.DayOfWeek;
import java.time.LocalTime;

import {wiringannotationfq};

import {testannotationfq};
import org.acme.schooltimetabling.domain.Lesson;
import org.acme.schooltimetabling.domain.Room;
import org.acme.schooltimetabling.domain.Timetable;
import org.acme.schooltimetabling.domain.Timeslot;
import org.junit.jupiter.api.Test;
import ai.timefold.solver.test.api.score.stream.ConstraintVerifier;

{testannotation}
class TimetableConstraintProviderTest {

    private static final Room ROOM = new Room("Room1");
    private static final Timeslot TIMESLOT1 = new Timeslot(DayOfWeek.MONDAY, LocalTime.of(9,0), LocalTime.NOON);
    private static final Timeslot TIMESLOT2 = new Timeslot(DayOfWeek.TUESDAY, LocalTime.of(9,0), LocalTime.NOON);

    {wiringannotation}
    ConstraintVerifier<TimetableConstraintProvider, Timetable> constraintVerifier;

    @Test
    void roomConflict() {
        Lesson firstLesson = new Lesson("1", "Subject1", "Teacher1", "Group1", TIMESLOT1, ROOM1);
        Lesson conflictingLesson = new Lesson("2", "Subject2", "Teacher2", "Group2", TIMESLOT1, ROOM1);
        Lesson nonConflictingLesson = new Lesson("3", "Subject3", "Teacher3", "Group3", TIMESLOT2, ROOM1);
        constraintVerifier.verifyThat(TimetableConstraintProvider::roomConflict)
                .given(firstLesson, conflictingLesson, nonConflictingLesson)
                .penalizesBy(1);
    }

}

Create the src/test/kotlin/org/acme/schooltimetabling/solver/TimetableConstraintProviderTest.kt class:

package org.acme.schooltimetabling.solver

import ai.timefold.solver.test.api.score.stream.ConstraintVerifier
import {testannotationfq}
import {wiringannotationfq}
import org.acme.schooltimetabling.domain.Lesson
import org.acme.schooltimetabling.domain.Room
import org.acme.schooltimetabling.domain.Timeslot
import org.acme.schooltimetabling.domain.Timetable
import org.junit.jupiter.api.Test
import java.time.DayOfWeek
import java.time.LocalTime

{testannotation}
class TimetableConstraintProviderTest {

    val ROOM1: Room = Room(1, "Room1")
    private val TIMESLOT1: Timeslot = Timeslot(1, DayOfWeek.MONDAY, LocalTime.NOON)
    private val TIMESLOT2: Timeslot = Timeslot(2, DayOfWeek.TUESDAY, LocalTime.NOON)

    {wiringannotation}
    lateinit var constraintVerifier: ConstraintVerifier<TimeTableConstraintProvider, Timetable>

    @Test
    fun roomConflict() {
        val firstLesson = Lesson("1", "Subject1", "Teacher1", "Group1", TIMESLOT1, ROOM1)
        val conflictingLesson = Lesson("2", "Subject2", "Teacher2", "Group2", TIMESLOT1, ROOM1)
        val nonConflictingLesson = Lesson("3", "Subject3", "Teacher3", "Group3", TIMESLOT2, ROOM1)
        constraintVerifier.verifyThat(TimeTableConstraintProvider::roomConflict)
            .given(firstLesson, conflictingLesson, nonConflictingLesson)
            .penalizesBy(1)
    }

}

This test verifies that the constraint TimetableConstraintProvider::roomConflict, when given three lessons in the same room, where two lessons have the same timeslot, it penalizes with a match weight of 1. So with a constraint weight of 10hard it would reduce the score by -10hard.

Notice how ConstraintVerifier ignores the constraint weight during testing - even if those constraint weights are hard coded in the ConstraintProvider - because constraints weights change regularly before going into production. This way, constraint weight tweaking does not break the unit tests.