public void testConjunctionVariable() {
PrologEngine engine = setupConjunction();
Variable variableX = new Variable("X");
Variable variableY = new Variable("Y");
Variable variableZ = new Variable("Z");
Predicate question = new Predicate("three", 3, variableX, variableY, variableZ);
Result answer = engine.askQuestion(question);
assertTrue(answer.hasAnswer());
assertEquals(new Constant("one"), variableX.getBinding());
assertEquals(new Constant("two"), variableY.getBinding());
assertEquals(new Constant("two"), variableZ.getBinding());
answer.next();
assertFalse(answer.hasAnswer());
}
public void testDisjunctionVariable() {
PrologEngine engine = setupDisjunction();
Variable variableY = new Variable("Y");
Result result3 = engine.askQuestion(new Predicate("hello", 1, variableY));
assertTrue(result3.hasAnswer());
assertEquals(new Constant("world"), variableY.getBinding());
result3.next();
assertTrue(result3.hasAnswer());
assertEquals(new Constant("mars"), variableY.getBinding());
result3.next();
assertTrue(result3.hasAnswer());
assertEquals(new Constant("venus"), variableY.getBinding());
}
public void testConjunctionBacktrackingVariable() {
PrologEngine engine = setupConjunctionBacktracking();
Variable variableX = new Variable("X");
Predicate question = new Predicate("suitable", 1, variableX);
Result answer = engine.askQuestion(question);
assertTrue(answer.hasAnswer());
assertEquals(new Constant("Eric"), variableX.getBinding());
answer.next();
assertFalse("Only one answer expected", answer.hasAnswer());
}