import java.util.Set;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

/**
 * Abstract base class for testing implementations of {@link Graph} interface. Graph instances
 * created for testing should have Integer node and String edge objects.
 *
 * <p>Test cases that should be handled similarly in any graph implementation are included in this
 * class. For example, testing that {@code nodes()} method returns the set of the nodes in the

import java.util.Set;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

/**
 * Abstract base class for testing implementations of {@link Graph} interface. Graph instances
 * created for testing should have Integer node and String edge objects.
 *
 * <p>Test cases that should be handled similarly in any graph implementation are included in this
 * class. For example, testing that {@code nodes()} method returns the set of the nodes in the