// Check that $nin is the opposite of $in SERVER-3264

t = db.jstests_nin2;
t.drop();

// Check various operator types.
function checkOperators(array, inMatches) {
    inCount = inMatches ? 1 : 0;
    notInCount = 1 - inCount;
    assert.eq(inCount, t.count({foo: {$in: array}}));
    assert.eq(notInCount, t.count({foo: {$not: {$in: array}}}));
    assert.eq(notInCount, t.count({foo: {$nin: array}}));
    assert.eq(inCount, t.count({foo: {$not: {$nin: array}}}));
}

t.save({});

assert.eq(1, t.count({foo: null}));
assert.eq(0, t.count({foo: {$ne: null}}));
assert.eq(0, t.count({foo: 1}));

// Check matching null against missing field.
checkOperators([null], true);
checkOperators([null, 1], true);
checkOperators([1, null], true);

t.remove({});
t.save({foo: null});

assert.eq(1, t.count({foo: null}));
assert.eq(0, t.count({foo: {$ne: null}}));
assert.eq(0, t.count({foo: 1}));

// Check matching empty set.
checkOperators([], false);

// Check matching null against missing null field.
checkOperators([null], true);
checkOperators([null, 1], true);
checkOperators([1, null], true);

t.remove({});
t.save({foo: 1});

assert.eq(0, t.count({foo: null}));
assert.eq(1, t.count({foo: {$ne: null}}));
assert.eq(1, t.count({foo: 1}));

// Check matching null against 1.
checkOperators([null], false);
checkOperators([null, 1], true);
checkOperators([1, null], true);

t.remove({});
t.save({foo: [0, 1]});
// Check exact match of embedded array.
checkOperators([[0, 1]], true);

t.remove({});
t.save({foo: []});
// Check exact match of embedded empty array.
checkOperators([[]], true);

t.remove({});
t.save({foo: 'foo'});
// Check regex match.
checkOperators([/o/], true);