Cleanup stack traces for test assertions

spec/env/common.js

@@ -1,11 +1,27 @@
+var AssertError;
+if (Error.captureStackTrace) {
+  AssertError = function AssertError(message, caller) {
+    Error.prototype.constructor.call(this, message);
+    this.message = message;
+
+    if (Error.captureStackTrace) {
+      Error.captureStackTrace(this, caller || AssertError);
+    }
+  };
+
+  AssertError.prototype = new Error();
+} else {
+  AssertError = Error;
+}
+
 global.shouldCompileTo = function(string, hashOrArray, expected, message) {
   shouldCompileToWithPartials(string, hashOrArray, false, expected, message);
 };
 
-global.shouldCompileToWithPartials = function(string, hashOrArray, partials, expected, message) {
+global.shouldCompileToWithPartials = function shouldCompileToWithPartials(string, hashOrArray, partials, expected, message) {
   var result = compileWithPartials(string, hashOrArray, partials);
   if (result !== expected) {
-    throw new Error("'" + result + "' should === '" + expected + "': " + message);
+    throw new AssertError("'" + result + "' should === '" + expected + "': " + message, shouldCompileToWithPartials);
   }
 };
 
@@ -31,9 +47,9 @@ global.compileWithPartials = function(string, hashOrArray, partials) {
 };
 
 
-global.equals = global.equal = function(a, b, msg) {
+global.equals = global.equal = function equals(a, b, msg) {
   if (a !== b) {
-    throw new Error("'" + a + "' should === '" + b + "'" + (msg ? ': ' + msg : ''));
+    throw new AssertError("'" + a + "' should === '" + b + "'" + (msg ? ': ' + msg : ''), equals);
   }
 };
 
@@ -44,13 +60,13 @@ global.shouldThrow = function(callback, type, msg) {
     failed = true;
   } catch (err) {
     if (type && !(err instanceof type)) {
-      throw new Error('Type failure: ' + err);
+      throw new AssertError('Type failure: ' + err);
     }
     if (msg && !(msg.test ? msg.test(err.message) : msg === err.message)) {
       equal(msg, err.message);
     }
   }
   if (failed) {
-    throw new Error('It failed to throw');
+    throw new AssertError('It failed to throw', shouldThrow);
   }
 };