Fix review nit, add test

src/providers/memory.js

@@ -8,10 +8,14 @@ define(function(require) {
   var createDB = (function() {
     var pool = {};
     return function getOrCreate(name) {
-      if(!pool[name]) {
+      var firstAccess = !pool.hasOwnProperty(name);
+      if(firstAccess) {
         pool[name] = {};
       }
-      return pool[name];
+      return {
+        firstAccess: firstAccess, 
+        db: pool[name]
+      };
     };
   }());
 
@@ -62,15 +66,16 @@ define(function(require) {
 
   function Memory(name) {
     this.name = name || FILE_SYSTEM_NAME;
-    this.db = createDB(this.name);
   }
   Memory.isSupported = function() {
     return true;
   };
 
   Memory.prototype.open = function(callback) {
+    var result = createDB(this.name);
+    this.db = result.db;
     asyncCallback(function() {
-      callback(null, true);
+      callback(null, result.firstAccess);
     });
   };
   Memory.prototype.getReadOnlyContext = function() {

tests/spec/providers/providers.memory.spec.js

@@ -12,6 +12,39 @@ define(["Filer"], function(Filer) {
       expect(memoryProvider.getReadWriteContext).to.be.a('function');
     });
 
+    describe("Memory provider DBs are sharable", function() {
+      it("should share a single memory db when name is the same", function(done) {
+        var provider1;
+	var provider2;
+        var provider3;
+        var name1 = 'memory-db';
+        var name2 = 'memory-db2';
+
+        provider1 = new Filer.FileSystem.providers.Memory(name1);
+          provider1.open(function(error, firstAccess) {
+            expect(error).not.to.exist;
+            expect(firstAccess).to.be.true;
+
+            provider2 = new Filer.FileSystem.providers.Memory(name1);
+            provider2.open(function(error, firstAccess) {
+              expect(error).not.to.exist;
+              expect(firstAccess).to.be.false;
+              expect(provider1.db).to.equal(provider2.db);
+
+              provider3 = new Filer.FileSystem.providers.Memory(name2);
+              provider3.open(function(error, firstAccess) {
+                expect(error).not.to.exist;
+                expect(firstAccess).to.be.true;
+                expect(provider3.db).not.to.equal(provider2.db);
+
+                done();
+	      });
+	    });
+	  });
+        });
+      });
+    });
+
     describe("open an Memory provider", function() {
       it("should open a new Memory database", function(done) {
         var provider = new Filer.FileSystem.providers.Memory();