made docs about beforeNotify clearer and tests a little safer

README.md

@@ -240,8 +240,7 @@ Bugsnag.appVersion = "2.0.14";
 
 To have more fine grained control over what errors are sent to Bugsnag, you can
 implement a `beforeNotify` function. If you want to halt the notification completely,
-return `false` from this function. You can also add metaData by editing the `metaData`
-parameter.
+return `false` from this function.
 
 ```javascript
 Bugsnag.beforeNotify = function(payload) {
@@ -251,6 +250,15 @@ Bugsnag.beforeNotify = function(payload) {
 }
 ```
 
+You can modify the `payload` or `metaData` by editing the parameters.
+
+```javascript
+Bugsnag.beforeNotify = function(payload, metaData) {
+  // Filter out sensitive information
+  payload.url = "http://redacted.com";
+}
+```
+
 The `payload` parameter contains the error's `name`, `message`, `file` and
 `lineNumber` where available, as well as some additional fields that we either
 show on your Bugsnag dashboard, or use for grouping.

test/test.bugsnag.js

@@ -223,6 +223,7 @@ describe("Bugsnag", function () {
       Bugsnag.notifyException(new Error("Example error"));
 
       assert.equal(requestData().params.url, "http://redacted.com");
+      assert(Bugsnag.testRequest.called, "Bugsnag.testRequest should have been called");
     });
 
     it("should contain 'warning' as the default severity", function () {