Mark the bottom of the stack everytime we start a new self test.

tmeasday · tmeasday · commit 1344228a51e5 · 2016-05-06T15:11:32.000-07:00
Because longjohn was collecting frames across runs of self test in the loop, we were actually seeing frame lists that applied to more than one test. 

This wasn't actually causing problems except in our frame parsing tests, but you can imagine that it would be quite unhelpful.
diff --git a/tools/tests/parse-stack-test.js b/tools/tests/parse-stack-test.js
@@ -12,11 +12,8 @@ selftest.define("parse-stack - parse stack traces without fibers", () => {
   const firstFilePath = files.convertToStandardPath(parsedStack[0].file);
   selftest.expectEqual(_.last(firstFilePath.split("/")), "parse-stack-test.js");
 
-  // This is no longer true as longjohn adds a bunch of pre-app frames to the
-  // call stack. However it doesn't seem we actually rely on this behavior
-  // anywhere
-  // const lastFilePath = files.convertToStandardPath(_.last(parsedStack).file);
-  // selftest.expectEqual(_.last(lastFilePath.split("/")), "main.js");
+  const lastFilePath = files.convertToStandardPath(_.last(parsedStack).file);
+  selftest.expectEqual(_.last(lastFilePath.split("/")), "selftest.js");
 
   markBottom(() => {
     const markedErr = new Error();
diff --git a/tools/tool-testing/selftest.js b/tools/tool-testing/selftest.js
@@ -1851,7 +1851,10 @@ var runTests = function (options) {
     try {
       runningTest = test;
       var startTime = +(new Date);
-      test.f(options);
+      // ensure we mark the bottom of the stack each time we start a new test
+      parseStack.markBottom(() => {
+        test.f(options);
+      })();
     } catch (e) {
       failure = e;
     } finally {
