diff --git a/lib/specs/spec_0_1.js b/lib/specs/spec_0_1.js
index 3933e40..30465f4 100644
--- a/lib/specs/spec_0_1.js
+++ b/lib/specs/spec_0_1.js
@@ -57,7 +57,28 @@ Spec_0_1.prototype.time = function(_time){
   return this;
 }
 
-//TODO another attributes . . .
+Spec_0_1.prototype.schemaurl = function(_schemaurl){
+  this.payload['schemaURL'] = _schemaurl;
+  return this;
+}
+
+Spec_0_1.prototype.contenttype = function(_contenttype){
+  this.payload['contentType'] = _contenttype;
+  return this;
+}
+
+Spec_0_1.prototype.data = function(_data){
+  this.payload['data'] = _data;
+  return this;
+}
+
+Spec_0_1.prototype.addExtension = function(key, value){
+  if(!this.payload['extensions']){
+    this.payload['extensions'] = {};
+  }
+  this.payload['extensions'][key] = value;
+  return this;
+}
 
 module.exports = Spec_0_1;
 
diff --git a/test/cloudevent_spec_0_1.js b/test/cloudevent_spec_0_1.js
index 66bf5b1..a7c060c 100644
--- a/test/cloudevent_spec_0_1.js
+++ b/test/cloudevent_spec_0_1.js
@@ -4,6 +4,10 @@ var Cloudevent   = require("../index.js");
 const type   = "com.github.pull.create";
 const source = "urn:event:from:myapi/resourse/123";
 const time   = new Date();
+const schemaurl = "http://example.com/registry/myschema.json";
+const contenttype = "application/json";
+const data = {};
+const extensions = {};
 
 var cloudevent = new Cloudevent()
                        .type(type)
@@ -18,6 +22,11 @@ describe("CloudEvents Spec 0.1 - JavaScript SDK", () => {
         expect(cloudevent.format()).to.have.property('eventType');
       });
 
+      it("requires 'eventTypeVersion'", () => {
+        cloudevent.eventTypeVersion("1.0");
+        expect(cloudevent.format()).to.have.property('eventTypeVersion');
+      });
+
       it("requires 'cloudEventsVersion'", () => {
         expect(cloudevent.format()).to.have.property('cloudEventsVersion');
       });
@@ -31,11 +40,38 @@ describe("CloudEvents Spec 0.1 - JavaScript SDK", () => {
       });
     });
 
-    describe("Backward compatibility", () => {
-      it("should have 'eventTypeVersion'", () => {
-        cloudevent.eventTypeVersion("1.0");
-        expect(cloudevent.format()).to.have.property('eventTypeVersion');
+    describe("Optional context attributes", () => {
+      it("contains 'eventTime'", () => {
+        cloudevent.time(time);
+        expect(cloudevent.format()).to.have.property('eventTime');
       });
+
+      it("contains 'schemaURL'", () => {
+        cloudevent.schemaurl(schemaurl);
+        expect(cloudevent.format()).to.have.property('schemaURL');
+      });
+
+      it("contains 'contentType'", () => {
+        cloudevent.contenttype(contenttype);
+        expect(cloudevent.format()).to.have.property('contentType');
+      });
+
+      it("contains 'data'", () => {
+        cloudevent.data(data);
+        expect(cloudevent.format()).to.have.property('data');
+      });
+      
+      it("contains 'extensions'", () => {
+        cloudevent.addExtension('foo', 'value');
+        expect(cloudevent.format()).to.have.property('extensions');
+      });
+
+      it("'extensions' should have 'bar' extension", () => {
+        cloudevent.addExtension('bar', 'value');
+        expect(cloudevent.format().extensions)
+          .to.have.property('foo');
+      });
+    
     });
 
     describe("The Constraint check", () => {