var a, b, c, col, otherCol, additions, removals, resets;
module('Backbone.Shard', {
    setup: function() {
        a = new Backbone.Model({data: 'a'});
        b = new Backbone.Model({data: 'b'});
        c = new Backbone.Model({data: 'c'});
        col = new Backbone.Collection([a, b, c]);
        otherCol = new Backbone.Collection();
        
        additions = 0;
        removals = 0;
        resets = 0;
    }
});
test('All-exclusive filter function, collection is prepopulated', function() {
    var shard = new Backbone.Shard({
        collection: col,
        filter: function() { return false; }
    });
    
    equal(shard.size(), 0, 'shard is empty');
    equal(shard.first(), undefined, 'nothing is the first element');
    equal(shard.last(), undefined, 'nothing is the last element');
});
test('All-exclusive filter function, collection populated dynamically', function() {
    var shard = new Backbone.Shard({
        collection: otherCol,
        filter: function() { return false; }
    });
    
    shard.on('add', function() {
        additions++;
    }).on('remove', function() {
        removals++;
    }).on('reset', function() {
        resets++;
    });
    
    otherCol.add([a, b, c]);
    equal(additions, 0, 'adding models not matching shard filter to collection does not trigger add events');
    equal(shard.size(), 0, '... and the shard is empty');
    
    otherCol.remove([a, b, c]);
    equal(removals, 0, 'removing models not matching shard filter from collection does not trigger remove events');
    equal(shard.size(), 0, '... and the shard is empty');
    
    otherCol.reset([a, b, c]);
    equal(resets, 1, 'resetting collection triggers reset events');
    equal(shard.size(), 0, '... and the shard is empty');
});
test('All-inclusive filter function, collection is prepopulated', function() {
    var shard = new Backbone.Shard({
        collection: col,
        filter: function() { return true; }
    });
    
    equal(shard.size(), 3, 'shard has 3 items');
    equal(shard.first(), a, 'a is the first element');
    equal(shard.indexOf(b), 1, 'b is the second element');
    equal(shard.last(), c, 'c is the last element');
});
test('All-inclusive filter function, collection populated dynamically', function() {
    var shard = new Backbone.Shard({
        collection: otherCol,
        filter: function() { return true; }
    });
    
    shard.on('add', function() {
        additions++;
    }).on('remove', function() {
        removals++;
    }).on('reset', function() {
        resets++;
    });
    
    otherCol.add([a, b, c]);
    equal(additions, 3, 'adding models matching shard filter to collection triggers add events');
    equal(shard.size(), 3, '... and the shard has 3 items');
    
    otherCol.remove([a, b, c]);
    equal(removals, 3, 'removing models matching shard filter from collection triggers remove events');
    equal(shard.size(), 0, '... and the shard is empty');
    otherCol.reset([a, b, c]);
    equal(resets, 1, 'resetting collection triggers reset events');
    equal(shard.size(), 3, '... and the shard has 3 items');
});