feat(tests): add helper to eval a module

Needed later for unit tests for code gen and runtime code
in #3605

modules/angular2/test/compiler/eval_module.ts

@@ -0,0 +1,33 @@
+import {Promise, PromiseWrapper} from 'angular2/src/core/facade/async';
+import {isPresent, global} from 'angular2/src/core/facade/lang';
+
+var evalCounter = 0;
+
+function nextModuleName() {
+  return `evalScript${evalCounter++}`;
+}
+
+export function evalModule(moduleSource: string, moduleImports: string[][], args: any[]):
+    Promise<any> {
+  var moduleName = nextModuleName();
+  var moduleSourceWithImports = [];
+  var importModuleNames = [];
+  moduleImports.forEach(sourceImport => {
+    var modName = sourceImport[0];
+    var modAlias = sourceImport[1];
+    importModuleNames.push(modName);
+    moduleSourceWithImports.push(`var ${modAlias} = require('${modName}');`);
+  });
+  moduleSourceWithImports.push(moduleSource);
+
+  var moduleBody = new Function('require', 'exports', 'module', moduleSourceWithImports.join('\n'));
+  var System = global['System'];
+  if (isPresent(System) && isPresent(System.registerDynamic)) {
+    System.registerDynamic(moduleName, importModuleNames, false, moduleBody);
+    return <Promise<any>>System.import(moduleName).then((module) => module.run(args));
+  } else {
+    var exports = {};
+    moduleBody(require, exports, {});
+    return PromiseWrapper.resolve(exports['run'](args));
+  }
+}