Toward #3: First crack at throws

test.js

@@ -81,9 +81,17 @@ Test.prototype = {
     this.complete();
     return this.report();
   },
-  /////////////////////////////////////////////////////////////////////
-  pass(message) {
-    this.outcomes.push({type: 'pass', message: message});
+  report() {
+    return this.outcomes;
+  },
+  /**
+   * 
+   * 
+   * @param {string} message
+   * @param {string} operator
+   */
+  pass(message, operator) {
+    this.outcomes.push({type: 'pass', operator: operator, message: message});
   },
   /**
    * 
@@ -150,6 +158,7 @@ Test.prototype = {
       );
     }
   },
+  //////////// Assertions //////////// 
   true(actual, message) {
     // TODO: Check this.isEnded
     message = message || `false`;
@@ -164,15 +173,44 @@ Test.prototype = {
       );
     }
   },
+  false(actual, message) {
+    return this.true(
+      !actual, 
+      message
+    );
+  },
   equal(actual, expected, message) {
     return this.true(
       expected === actual, 
       message
     );
   },
-  report() {
-    return this.outcomes;
-  }
+
+  /**
+   * Assert that the function call fn() throws an exception. expected, if present, 
+   * must be a RegExp or Function. The RegExp matches the string representation of 
+   * the exception, as generated by err.toString(). The Function is the exception 
+   * thrown (e.g. Error). msg is an optional description of the assertion. 
+   * 
+   * @param {function} fn
+   * @param {Error} expected
+   * @param {string} message
+   * @returns void
+   */
+  throws(fn, expected, message) {
+    let actual;
+    try {
+      fn();
+    } catch (error) {
+      if(error instanceof expected) {
+        this.pass(message, 'throws');
+        return;
+      } else {
+        actual = error;
+      }
+    }
+    this.fail(message, expected, actual, StackTrace.parse(actual));
+  },
 }
 
 function test(name, impl) {