package coffee.liz.lambda.eval;

import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
import org.mockito.Mockito;

import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.Supplier;

public class ThunkTest {
	@Test
	public void testThunkNonNull() {
		final AtomicInteger invok = new AtomicInteger(0);
		final Supplier<Integer> i = () -> {
			invok.incrementAndGet();
			return invok.get();
		};
		final Thunk<Integer> thunk = new Thunk<>(i);
		Assertions.assertEquals(1, thunk.get());
		Assertions.assertEquals(1, thunk.get());
		Assertions.assertEquals(1, thunk.get());
		Assertions.assertEquals(1, invok.get());
	}

	@Test
	public void testThunkNull() {
		final AtomicInteger invok = new AtomicInteger(0);
		final Supplier<Integer> i = () -> {
			invok.incrementAndGet();
			return null;
		};
		final Thunk<Integer> thunk = new Thunk<>(i);
		Assertions.assertNull(thunk.get());
		Assertions.assertNull(thunk.get());
		Assertions.assertNull(thunk.get());
		Assertions.assertEquals(1, invok.get());
	}
}