Added coverage

.gitignore

@@ -3,3 +3,4 @@
 *.swo
 node_modules
 npm-debug.log
+test/.coverage

.npmignore

@@ -3,3 +3,4 @@ example
 node_modules
 .gitignore
 .npmignore
+test/.coverage

README.md

@@ -144,10 +144,26 @@ arguments that was passed to the final callback.
 
 `npm test`
 
-or 
+Test scripts also support TAP when executed individually. You can use a tap consumer (such as [node-tap](https://github.com/isaacs/node-tap)) to consume 
+all tests:
 
 `tap test`
 
-or
+# test coverage
 
-`jasmine-node test`
+Test coverage reporting requires you to have [istanbul](https://github.com/gotwarlost/istanbul) installed. 
+
+`npm install -g istanbul`
+
+Then you can run the coverage report:
+
+`npm run-script coverage`
+
+```
+=============================== Coverage summary ===============================
+Statements   : 100% ( 39/39 )
+Branches     : 100% ( 8/8 )
+Functions    : 100% ( 12/12 )
+Lines        : 100% ( 39/39 )
+================================================================================
+```

package.json

@@ -18,7 +18,8 @@
         ],
         "main": "./index.js",
         "scripts": {
-            "test": "jasmine-node test; echo >&2 'Tests support TAP. Use node-tap and consume TAP output with \"tap test\".'"
+            "test": "jasmine-node test",
+            "coverage": "istanbul cover --print summary --dir ./test/.coverage jasmine-node -- test 2> /dev/null || echo 'Istanbul required for test coverage reports: npm install -g istanbul'"
         },
         "engine": {
             "node": ">=0.8.8"