Implement ownProperty() and inheritFrom() assertions in should()

third_party/WebKit/LayoutTests/webaudio/resources/audit.js

Index: third_party/WebKit/LayoutTests/webaudio/resources/audit.js
diff --git a/third_party/WebKit/LayoutTests/webaudio/resources/audit.js b/third_party/WebKit/LayoutTests/webaudio/resources/audit.js
index d2946161efbb1f2cd2f707a8d6487db5145ddee8..0ed38805798a3c2959c31154eb7c36f7b53b697e 100644
--- a/third_party/WebKit/LayoutTests/webaudio/resources/audit.js
+++ b/third_party/WebKit/LayoutTests/webaudio/resources/audit.js
@@ -964,6 +964,54 @@ window.Audit = (function () {
                           '${actual} ' + passDetail,
                           '${actual} ' + failDetail);
     }
+
+    /**
+     * Check if |expected| property is truly owned by |actual| object.
+     *
+     * @example
+     *   should(BaseAudioContext.prototype,
+     *          'BaseAudioContext.prototype').ownProperty('createGain');
+     *
+     * @result
+     *   "PASS   BaseAudioContext.prototype has an own property of
+     *       'createGain'."
+     */
+    ownProperty() {

[Raymond Toy, 2017/04/06 23:13:14]

ownProperty or beOwnPropertyOf (as mentioned in the bug)?

[hongchan, 2017/04/07 15:55:36]

I think this is cleaner. Let me know if you think otherwise. (You're the primary
customer!)

[Raymond Toy, 2017/04/07 16:10:58]

Maybe

should(obj).haveOwnProperty(property)

?  beOwnPropertyOf is backwards.

[hongchan, 2017/04/07 17:22:16]

I llke haveOwnProperty().

+      this._processArguments(arguments);
+
+      return this._assert(
+          this._actual.hasOwnProperty(this._expected),
+          '${actual} has an own property of "${expected}".',
+          '${actual} does not own the property of "${expected}".');
+    }
+
+
+    /**
+     * Check if an object is inherited from a class. This looks up the entire
+     * prototype chain of a given object and tries to find a match.
+     *
+     * @example
+     *   should(sourceNode, 'A buffer source node')
+     *       .inheritFrom('AudioScheduledSourceNode');
+     *
+     * @result
+     *   "PASS   A buffer source node inherits from 'AudioScheduledSourceNode'."
+     */
+    inheritFrom() {
+      this._processArguments(arguments);
+
+      let prototypes = [];
+      let currentPrototype = Object.getPrototypeOf(this._actual);
+      while (currentPrototype) {
+        prototypes.push(currentPrototype.constructor.name);
+        currentPrototype = Object.getPrototypeOf(currentPrototype);
+      }
+
+      return this._assert(
+          prototypes.includes(this._expected),
+          '${actual} inherits from "${expected}".',
+          '${actual} does not inherit from "${expected}".');
+    }
   }