[Events] More general view policy

The Messages view policy now will allow any object
that has a telemetry type of string to have access
to the Messages view, not just Event List
Generators. (The test for this still does not work
though.) #18.

platform/features/events/src/policies/MessagesViewPolicy.js

@@ -35,6 +35,16 @@ define(
          */
         function MessagesViewPolicy() {
             
+            function hasStringTelemetry(domainObject) {
+                var telemetry = domainObject &&
+                        domainObject.getCapability('telemetry'),
+                    metadata = telemetry ? telemetry.getMetadata() : {},
+                    ranges = metadata.ranges || [];
+
+                return ranges.some(function (range) {
+                    return range.format === 'string';
+                });
+            }
             return {
                 /**
                  * Check whether or not a given action is allowed by this
@@ -47,12 +57,10 @@ define(
                     // This policy only applies for the Messages view
                     if (view.key === 'messages') {
                         // The Messages view is allowed only if the domain 
-                        // object is a Event Message Generator
+                        // object has string telemetry
-                        if (domainObject.getModel().type !== 'eventGenerator') {
+                        if (!hasStringTelemetry(domainObject)) {
                             return false;
                         }
-                        
-                        // TODO: This may later apply to more types beyond just eventGenerator.
                     }
                     
                     // Like all policies, allow by default.

platform/features/events/test/policies/MessagesViewPolicySpec.js

@@ -32,6 +32,7 @@ define(
         describe("The messages view policy", function () {
             var mockDomainObject,
                 testType,
+                telemetryType,
                 policy;
 
             beforeEach(function () {
@@ -42,18 +43,18 @@ define(
                 mockDomainObject.getModel.andCallFake(function (c) {
                     return {type: testType};
                 });
-
+                
                 policy = new MessagesViewPolicy();
             });
 
-            it("disallows the message view for non Event Generators", function () {
+            it("disallows the message view for objects without string telemetry", function () {
-                testType = 'notAnEventGenerator';
+                telemetryType = 'notString';
                 expect(policy.allow({ key: 'messages' }, mockDomainObject))
                     .toBeFalsy();
             });
 
-            it("allows the message view for Event Generators", function () {
+            it("allows the message view for objects with string telemetry", function () {
-                testType = 'eventGenerator';
+                telemetryType = 'string';
                 expect(policy.allow({ key: 'messages' }, mockDomainObject))
                     .toBeTruthy();
             });