t = db.find5;
t.drop();

t.save({a: 1});
t.save({b: 5});

assert.eq(2, t.find({}, {b: 1}).count(), "A");

function getIds(f) {
    return t.find({}, f).map(function(z) {
        return z._id;
    });
}

assert.eq(Array.tojson(getIds(null)), Array.tojson(getIds({})), "B1 ");
assert.eq(Array.tojson(getIds(null)), Array.tojson(getIds({a: 1})), "B2 ");
assert.eq(Array.tojson(getIds(null)), Array.tojson(getIds({b: 1})), "B3 ");
assert.eq(Array.tojson(getIds(null)), Array.tojson(getIds({c: 1})), "B4 ");

x = t.find({}, {a: 1})[0];
assert.eq(1, x.a, "C1");
assert.isnull(x.b, "C2");

x = t.find({}, {a: 1})[1];
assert.isnull(x.a, "C3");
assert.isnull(x.b, "C4");

x = t.find({}, {b: 1})[0];
assert.isnull(x.a, "C5");
assert.isnull(x.b, "C6");

x = t.find({}, {b: 1})[1];
assert.isnull(x.a, "C7");
assert.eq(5, x.b, "C8");

t.drop();

t.save({a: 1, b: {c: 2, d: 3, e: 4}});
assert.eq(2, t.find({}, {"b.c": 1}).toArray()[0].b.c, "D");

o = t.find({}, {"b.c": 1, "b.d": 1}).toArray()[0];
assert(o.b.c, "E 1");
assert(o.b.d, "E 2");
assert(!o.b.e, "E 3");

assert(!t.find({}, {"b.c": 1}).toArray()[0].b.d, "F");

t.drop();
t.save({a: {b: {c: 1}}});
assert.eq(1, t.find({}, {"a.b.c": 1})[0].a.b.c, "G");