Make this inside a concatenated module the global object.

Per http://esdiscuss.org/topic/this-if-the-global-object-is-not-in-the-scope-chain.

lib/utils.js

@@ -53,20 +53,24 @@ exports.sourcePosition = sourcePosition;
 
 function IFFE() {
   if (!IFFE.AST) {
-    IFFE.AST = JSON.stringify(recast.parse('(function(){})()', { esprima: esprima }));
+    IFFE.AST = JSON.stringify(
+      recast.parse('(function(){}).call(this)', { esprima: esprima })
+    );
   }
 
   var result = JSON.parse(IFFE.AST);
-  var body = result.program.body[0].expression.callee.body.body;
+  var expression = result.program.body[0].expression;
+  var body = expression.callee.object.body.body;
 
-  Array.prototype.slice.call(arguments).forEach(function(arg) {
+  var args = Array.prototype.slice.call(arguments);
+  args.forEach(function(arg) {
     if (Object.prototype.toString.call(arg) === '[object Array]') {
       body.push.apply(body, arg);
     } else {
       body.push(arg);
     }
   });
 
-  return result.program.body[0].expression;
+  return expression;
 }
 exports.IFFE = IFFE;

test/examples/module-from/importer.js

@@ -8,7 +8,7 @@ assert.deepEqual(Object.keys(things).sort(), ['count', 'incr']);
 // can't add keys
 assert.throws(function() {
   things.iAmNotReal = 1;
-}, TypeError);
+}, /Can't add property iAmNotReal, object is not extensible/);
 
 // can't replace keys
 assert.throws(function() {

test/examples/this-is-global/mod.js

@@ -0,0 +1,8 @@
+/* jshint esnext:true */
+
+assert.strictEqual(
+  this,
+  global,
+  '`this` (keys=' + Object.keys(this) + ') does not equal ' +
+  '`global` (keys=' + Object.keys(global) + ')'
+);

test/runner.js

@@ -148,16 +148,17 @@ function requireTestFile(path, relativeTo, assert) {
 
   if (!testFileGlobal) { testFileGlobal = {}; }
 
-  vm.runInNewContext(code, {
-    assert: assert,
-    global: testFileGlobal,
-
-    module: mod,
-    exports: mod.exports,
-    require: function(requiredPath) {
-      return requireTestFile(requiredPath, Path.dirname(path), assert);
-    }
-  }, path);
+  testFileGlobal.assert = assert;
+  testFileGlobal.global = testFileGlobal;
+  testFileGlobal.module = mod;
+  testFileGlobal.exports = mod.exports;
+  testFileGlobal.require = function(requiredPath) {
+    return requireTestFile(requiredPath, Path.dirname(path), assert);
+  };
+
+  // Hack to work around an issue where vm does not set `this` to the context.
+  code = '(function(){' + code + '}).call(global);';
+  vm.runInNewContext(code, testFileGlobal, path);
 
   testFileCache[path] = mod.exports;
   return mod.exports;