t = db.group2;
t.drop();

t.save({a: 2});
t.save({b: 5});
t.save({a: 1});

cmd = {
    key: {a: 1},
    initial: {count: 0},
    reduce: function(obj, prev) {
        prev.count++;
    }
};

result = t.group(cmd);

assert.eq(3, result.length, "A");
assert.eq(null, result[1].a, "C");