public class IntHashSetTest {
    static int passed = 0, failed = 0;

    public static void main(String[] args) {
        testEmpty();
        testAddContains();
        testDuplicates();
        testNegatives();
        testManyForcingResize();
        testCollisions();
        System.out.println();
        System.out.println("Passed: " + passed + " / " + (passed + failed));
    }

    static void testEmpty() {
        IntHashSet s = new IntHashSet();
        checkBool("empty contains(5)", s.contains(5), false);
        checkBool("empty contains(-1)", s.contains(-1), false);
        checkBool("empty contains(0)", s.contains(0), false);
    }

    static void testAddContains() {
        IntHashSet s = new IntHashSet();
        s.add(1); s.add(2); s.add(3);
        checkBool("contains(1)", s.contains(1), true);
        checkBool("contains(2)", s.contains(2), true);
        checkBool("contains(3)", s.contains(3), true);
        checkBool("contains(4)", s.contains(4), false);
    }

    static void testDuplicates() {
        IntHashSet s = new IntHashSet();
        s.add(7); s.add(7); s.add(7); s.add(7);
        checkBool("dup contains(7)", s.contains(7), true);
        // no easy way to inspect size without exposing it; trust it
    }

    static void testNegatives() {
        IntHashSet s = new IntHashSet();
        s.add(-1); s.add(-100); s.add(Integer.MIN_VALUE);
        checkBool("contains(-1)", s.contains(-1), true);
        checkBool("contains(-100)", s.contains(-100), true);
        checkBool("contains(MIN_VALUE)", s.contains(Integer.MIN_VALUE), true);
        checkBool("contains(1) after negs", s.contains(1), false);
    }

    static void testManyForcingResize() {
        // Insert 100 values - capacity starts at 16, will resize multiple times
        IntHashSet s = new IntHashSet();
        for (int i = 0; i < 100; i++) s.add(i);
        for (int i = 0; i < 100; i++) {
            checkBool("post-resize contains(" + i + ")", s.contains(i), true);
        }
        checkBool("post-resize contains(100)", s.contains(100), false);
        checkBool("post-resize contains(-1)", s.contains(-1), false);
    }

    static void testCollisions() {
        // Values that all hash to bucket 0 in capacity 16 (multiples of 16)
        IntHashSet s = new IntHashSet();
        s.add(0); s.add(16); s.add(32); s.add(48);
        checkBool("collision contains(0)", s.contains(0), true);
        checkBool("collision contains(16)", s.contains(16), true);
        checkBool("collision contains(32)", s.contains(32), true);
        checkBool("collision contains(48)", s.contains(48), true);
        checkBool("collision contains(8)", s.contains(8), false);
        checkBool("collision contains(64)", s.contains(64), false);
    }

    static void checkBool(String label, boolean actual, boolean expected) {
        if (actual == expected) { System.out.println("PASS " + label + " = " + actual); passed++; }
        else { System.out.println("FAIL " + label + " expected=" + expected + " actual=" + actual); failed++; }
    }
}
