mongodb: fix get pagination count

MongoDatabase.get wasn't returning the right
number of pages and documents.

Since mongodb and connect-mongo upgrade all
documents were counted instead of counting only
the documents matching the filter.

lib/storages/databases/mongodb/MongoDatabase.js

@@ -412,7 +412,7 @@ MongoDatabase.prototype.get = function(collection, filter, fields, limit, page,
     function(error, documents) {
       if (error) return callback(error);
 
-      this.db.collection(collection).countDocuments(function(countError, count) {
+      this.db.collection(collection).countDocuments(filter, function(countError, count) {
         if (countError) return callback(countError);
 
         callback(null, documents || [], {

tests/server/storages/MongoDatabase.js

@@ -99,7 +99,7 @@ describe('MongoDatabase', function() {
 
     // Mock MongoDB Collection
     collection = {
-      countDocuments: chai.spy(function(callback) {
+      countDocuments: chai.spy(function(filter, callback) {
         callback(null, documents.length);
       }),
       find: chai.spy(function() {
@@ -928,10 +928,15 @@ describe('MongoDatabase', function() {
       var expectedFilter = new ResourceFilter().equal('field', 'value');
 
       collection.find = chai.spy(function(filter) {
-        assert.deepEqual(filter, MongoDatabase.buildFilter(expectedFilter), 'Wrong filter');
+        assert.deepEqual(filter, MongoDatabase.buildFilter(expectedFilter), 'Wrong find filter');
         return cursor;
       });
 
+      collection.countDocuments = chai.spy(function(filter, callback) {
+        assert.deepEqual(filter, MongoDatabase.buildFilter(expectedFilter), 'Wrong countDocuments filter');
+        callback(null, documents.length);
+      });
+
       database.get(expectedCollection, expectedFilter, null, null, null, null, function(error, results, pagination) {
         database.db.collection.should.have.been.called.exactly(2);
         database.db.collection.should.have.been.called.with(expectedCollection);
@@ -1107,7 +1112,7 @@ describe('MongoDatabase', function() {
     it('should execute callback with an error if counting documents failed', function(done) {
       var expectedError = new Error('Something went wrong');
 
-      collection.countDocuments = chai.spy(function(callback) {
+      collection.countDocuments = chai.spy(function(filter, callback) {
         callback(expectedError);
       });