Shorten the plan stack.

I'm not sure we need more than a depth of 1.

Author: jamestalmage

lib/test.js

@@ -77,7 +77,7 @@ Test.prototype._setAssertError = function (err) {
 	this.assertError = err;
 };
 
-Test.prototype.plan = function (count) {
+Test.prototype.plan = function (count, planStack) {
 	if (typeof count !== 'number') {
 		throw new TypeError('Expected a number');
 	}
@@ -86,7 +86,7 @@ Test.prototype.plan = function (count) {
 
 	// in case the `planCount` doesn't match `assertCount,
 	// we need the stack of this function to throw with a useful stack
-	this.planStack = new Error().stack;
+	this.planStack = planStack || new Error().stack;
 };
 
 Test.prototype._run = function () {
@@ -265,7 +265,6 @@ Test.prototype._publicApi = function () {
 
 function PublicApi(test) {
 	this._test = test;
-	this.plan = test.plan.bind(test);
 	this.skip = new SkipApi(test);
 }
 
@@ -303,6 +302,17 @@ PublicApi.prototype = enhanceAssert({
 	onError: onAssertionEvent
 });
 
+PublicApi.prototype.plan = plan;
+
+function plan(ct) {
+	var limitBefore = Error.stackTraceLimit;
+	Error.stackTraceLimit = 1;
+	var obj = {};
+	Error.captureStackTrace(obj, plan);
+	Error.stackTraceLimit = limitBefore;
+	this._test.plan(ct, obj.stack);
+}
+
 // Getters
 [
 	'assertCount',