Add test for T3026.

packages/babel-plugin-transform-async-to-generator/test/fixtures/export-async/import-and-export/actual.js

@@ -0,0 +1,3 @@
+import bar from 'bar';
+
+export async function foo () { }

packages/babel-plugin-transform-async-to-generator/test/fixtures/export-async/import-and-export/expected.js

@@ -0,0 +1,17 @@
+'use strict';
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.foo = undefined;
+
+var _bar = require('bar');
+
+var _bar2 = babelHelpers.interopRequireDefault(_bar);
+
+let foo = exports.foo = function () {
+  var ref = babelHelpers.asyncToGenerator(function* () {});
+  return function foo() {
+    return ref.apply(this, arguments);
+  };
+}();

packages/babel-plugin-transform-async-to-generator/test/fixtures/export-async/lone-export/actual.js

@@ -0,0 +1 @@
+export async function foo () { }

packages/babel-plugin-transform-async-to-generator/test/fixtures/export-async/lone-export/expected.js

@@ -0,0 +1,12 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+
+let foo = exports.foo = function () {
+  var ref = babelHelpers.asyncToGenerator(function* () {});
+  return function foo() {
+    return ref.apply(this, arguments);
+  };
+}();

packages/babel-plugin-transform-async-to-generator/test/fixtures/export-async/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["external-helpers", "transform-es2015-modules-commonjs", "transform-async-to-generator"]
+}