[#49,query][s]: introduce Query model object and use it in Dataset.

* tests: refactor Memory backend tests so that tests are independent (to avoid issues of carry over of query state)
* TODO: use query stuff in views - NB sorting seems broken in DataTable.

src/model.js

@@ -13,37 +13,31 @@ this.recline.Model = this.recline.Model || {};
 my.Dataset = Backbone.Model.extend({
   __type__: 'Dataset',
   initialize: function(model, backend) {
+    _.bindAll(this, 'query');
     this.backend = backend;
     if (backend && backend.constructor == String) {
       this.backend = my.backends[backend];
     }
     this.currentDocuments = new my.DocumentList();
     this.docCount = null;
-    this.defaultQuery = {
+    this.queryState = new my.Query();
-      size: 100
+    this.queryState.bind('change', this.query);
-      , offset: 0
-    };
-    // this.queryState = {};
   },
 
-  // ### getDocuments
+  // ### query
   //
-  // AJAX method with promise API to get rows (documents) from the backend.
+  // AJAX method with promise API to get documents from the backend.
+  //
+  // It will query based on current query state (given by this.queryState)
+  // updated by queryObj (if provided).
   //
   // Resulting DocumentList are used to reset this.currentDocuments and are
   // also returned.
-  //
-  // :param numRows: passed onto backend getDocuments.
-  // :param start: passed onto backend getDocuments.
-  //
-  // this does not fit very well with Backbone setup. Backbone really expects you to know the ids of objects your are fetching (which you do in classic RESTful ajax-y world). But this paradigm does not fill well with data set up we have here.
-  // This also illustrates the limitations of separating the Dataset and the Backend
   query: function(queryObj) {
     var self = this;
-    this.queryState = queryObj || this.defaultQuery;
+    this.queryState.set(queryObj, {silent: true});
-    this.queryState = _.extend({size: 100, offset: 0}, this.queryState);
     var dfd = $.Deferred();
-    this.backend.query(this, this.queryState).done(function(rows) {
+    this.backend.query(this, this.queryState.toJSON()).done(function(rows) {
       var docs = _.map(rows, function(row) {
         var _doc = new my.Document(row);
         _doc.backend = self.backend;
@@ -79,6 +73,13 @@ my.DocumentList = Backbone.Collection.extend({
   model: my.Document
 });
 
+my.Query = Backbone.Model.extend({
+  defaults: {
+    size: 100
+    , offset: 0
+  }
+});
+
 // ## Backend registry
 //
 // Backends will register themselves by id into this registry

test/model.test.js

@@ -1,13 +1,11 @@
 (function ($) {
 module("Dataset");
 
-test('Memory Backend', function () {
+var memoryData = {
-  var datasetId = 'test-dataset';
-  var inData = {
   metadata: {
     title: 'My Test Dataset'
     , name: '1-my-test-dataset' 
-      , id: datasetId
+    , id: 'test-dataset'
     , headers: ['x', 'y', 'z']
   },
   documents: [
@@ -19,17 +17,31 @@ test('Memory Backend', function () {
     , {id: 5, x: 6, y: 12, z: 18}
   ]
 };
+
+function makeBackendDataset() {
   var backend = new recline.Model.BackendMemory();
-  backend.addDataset(inData);
+  backend.addDataset(memoryData);
-  var dataset = new recline.Model.Dataset({id: datasetId}, backend);
+  var dataset = new recline.Model.Dataset({id: memoryData.metadata.id}, backend);
-  // ### Start testing
+  return dataset;
-  expect(10);
+}
-  // convenience for tests
+
-  var data = backend.datasets[datasetId];
+test('Memory Backend: basics', function () {
+  var dataset = makeBackendDataset();
+  expect(3);
+  // convenience for tests - get the data that should get changed
+  var data = dataset.backend.datasets[memoryData.metadata.id];
   dataset.fetch().then(function(datasetAgain) {
     equal(dataset.get('name'), data.metadata.name);
     deepEqual(dataset.get('headers'), data.metadata.headers);
     equal(dataset.docCount, 6);
+  });
+});
+
+test('Memory Backend: query', function () {
+  var dataset = makeBackendDataset();
+  // convenience for tests - get the data that should get changed
+  var data = dataset.backend.datasets[memoryData.metadata.id];
+  var dataset = makeBackendDataset();
   var queryObj = {
     size: 4
     , offset: 2
@@ -37,6 +49,12 @@ test('Memory Backend', function () {
   dataset.query(queryObj).then(function(documentList) {
     deepEqual(data.documents[2], documentList.models[0].toJSON());
   });
+});
+
+test('Memory Backend: query sort', function () {
+  var dataset = makeBackendDataset();
+  // convenience for tests - get the data that should get changed
+  var data = dataset.backend.datasets[memoryData.metadata.id];
   var queryObj = {
     sort: [
       ['y', 'desc']
@@ -46,6 +64,12 @@ test('Memory Backend', function () {
     var doc0 = dataset.currentDocuments.models[0].toJSON();
     equal(doc0.x, 6);
   });
+});
+ 
+test('Memory Backend: update and delete', function () {
+  var dataset = makeBackendDataset();
+  // convenience for tests - get the data that should get changed
+  var data = dataset.backend.datasets[memoryData.metadata.id];
   dataset.query().then(function(docList) {
     equal(docList.length, Math.min(100, data.documents.length));
     var doc1 = docList.models[0];
@@ -61,8 +85,7 @@ test('Memory Backend', function () {
     // Test Delete
     doc1.destroy().then(function() {
       equal(data.documents.length, 5);
-        equal(data.documents[0].x, inData.documents[1].x);
+      equal(data.documents[0].x, memoryData.documents[1].x);
-      });
     });
   });
 });