diff --git a/lib/assets.js b/lib/assets.js
index 8c31703..d69b101 100644
--- a/lib/assets.js
+++ b/lib/assets.js
@@ -137,7 +137,7 @@ AssetsExpander.YamlSyntaxError = function(message) {
   Error.call(this);
   Error.captureStackTrace(this, this.constructor);
 
-  this.name = this.constructor.name;
+  this.name = 'YamlSyntaxError';
   this.message = message;
 };
 AssetsExpander.YamlSyntaxError.prototype.__proto__ = Error.prototype;
@@ -146,7 +146,7 @@ AssetsExpander.UnknownGroupError = function(message) {
   Error.call(this);
   Error.captureStackTrace(this, this.constructor);
 
-  this.name = this.constructor.name;
+  this.name = 'UnknownGroupError';
   this.message = message;
 };
 AssetsExpander.UnknownGroupError.prototype.__proto__ = Error.prototype;
@@ -155,7 +155,7 @@ AssetsExpander.UnknownTypeError = function(message) {
   Error.call(this);
   Error.captureStackTrace(this, this.constructor);
 
-  this.name = this.constructor.name;
+  this.name = 'UnknownTypeError';
   this.message = message;
 };
 AssetsExpander.UnknownTypeError.prototype.__proto__ = Error.prototype;
diff --git a/test/assets-test.js b/test/assets-test.js
index d9cdf46..2bfae37 100644
--- a/test/assets-test.js
+++ b/test/assets-test.js
@@ -28,7 +28,11 @@ exports.yamlSuite = vows.describe('incorrect yaml').addBatch({
     'should give YAML error': function(topic) {
       assert.throws(function() {
         expanderFor(topic);
-      }, AssetsExpander.YamlSyntaxError);
+      }, function(err) {
+        if ((err instanceof AssetsExpander.YamlSyntaxError) && err.name == 'YamlSyntaxError' && /dedented/.test(err.message)) {
+          return true;
+        }
+      });
     }
   }
 });
@@ -151,14 +155,22 @@ exports.groupsSuite = vows.describe('expanding assets groups').addBatch({
     'should not fail': function(expanded) {
       assert.throws(function() {
         expanderFor('assets.yml').processGroup('unknown', 'type1', { type: 'css' });
-      }, AssetsExpander.UnknownTypeError);
+      }, function(err) {
+        if ((err instanceof AssetsExpander.UnknownTypeError) && err.name == 'UnknownTypeError' && /unknown/.test(err.message)) {
+          return true;
+        }
+      });
     }
   },
   'expand unknown group': {
     'should not fail': function(expanded) {
       assert.throws(function() {
         expanderFor('assets.yml').processGroup('stylesheets', 'type1', { type: 'css' });
-      }, AssetsExpander.UnknownGroupError);
+      }, function(err) {
+        if ((err instanceof AssetsExpander.UnknownGroupError) && err.name == 'UnknownGroupError' && /stylesheets/.test(err.message) && /type1/.test(err.message)) {
+          return true;
+        }
+      });
     }
   },
   'expanding group #1 from assets.yml': {