Test that ESM modules can be imported from npm packages.

With appropriate meteor.nodeModules.recompile configuration, that is.

tools/tests/apps/modules/package-lock.json

@@ -185,6 +185,14 @@
         "to-fast-properties": "^2.0.0"
       }
     },
+    "@polymer/lit-element": {
+      "version": "0.7.1",
+      "resolved": "https://registry.npmjs.org/@polymer/lit-element/-/lit-element-0.7.1.tgz",
+      "integrity": "sha512-aYSzVhC19l7xSm73aHI06VPcD/H+GxpFNZrhbJ+zVIpgAveOgGp5Ga7UtTBHQCdHlJbZ0dMlaBXMZ3twgXCokg==",
+      "requires": {
+        "lit-html": "^1.0.0-rc.2"
+      }
+    },
     "@wry/context": {
       "version": "0.4.0",
       "resolved": "https://registry.npmjs.org/@wry/context/-/context-0.4.0.tgz",
@@ -658,6 +666,11 @@
         "react": "16.4.1"
       }
     },
+    "lit-html": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/lit-html/-/lit-html-1.1.0.tgz",
+      "integrity": "sha512-ZDJHpJi09yknMpjwPI8fuSl5sUG7+pF+eE5WciFtgyX7zebvgMDBgSLq4knXa7grxM00RkQ7PBd7UZQiruA78Q=="
+    },
     "lodash": {
       "version": "4.17.11",
       "resolved": "https://registry.npmjs.org/lodash/-/lodash-4.17.11.tgz",

tools/tests/apps/modules/package.json

@@ -8,6 +8,7 @@
     "@babel/plugin-proposal-do-expressions": "^7.2.0",
     "@babel/plugin-proposal-optional-chaining": "^7.2.0",
     "@babel/runtime": "^7.4.5",
+    "@polymer/lit-element": "0.7.1",
     "@wry/context": "^0.4.0",
     "acorn": "file:imports/links/acorn",
     "aws-sdk": "^2.2.41",
@@ -36,6 +37,12 @@
     "test-packages": "TEST_BROWSER_DRIVER=puppeteer meteor test-packages --driver-package meteortesting:mocha packages/modules-test-package"
   },
   "meteor": {
-    "testModule": "tests.js"
+    "testModule": "tests.js",
+    "nodeModules": {
+      "recompile": {
+        "pify": "legacy",
+        "@polymer/lit-element": true
+      }
+    }
   }
 }

tools/tests/apps/modules/tests.js

@@ -371,6 +371,47 @@ describe("local node_modules", () => {
     assert.strictEqual(typeof parse, "function");
     assert.strictEqual(parse, nestedParse);
   });
+
+  Meteor.isClient && it("can import @polymer/lit-element", () => {
+    // This import is enabled by the meteor.nodeModules.recompile section of
+    // the package.json file for the modules test application.
+    const litElement = require("@polymer/lit-element");
+    const typeofMap = {};
+    Object.keys(litElement).forEach(key => {
+      typeofMap[key] = typeof litElement[key];
+    });
+
+    assert.deepEqual(typeofMap, {
+      defaultConverter: "object",
+      notEqual: "function",
+      UpdatingElement: "function",
+      customElement: "function",
+      property: "function",
+      query: "function",
+      queryAll: "function",
+      eventOptions: "function",
+      html: "function",
+      svg: "function",
+      TemplateResult: "function",
+      SVGTemplateResult: "function",
+      supportsAdoptingStyleSheets: "boolean",
+      CSSResult: "function",
+      css: "function",
+      LitElement: "function"
+    });
+  });
+
+  it("can import @babel/runtime/helpers/esm/*", () => {
+    function check(exports) {
+      assert.strictEqual(typeof exports.default, "function");
+    }
+    check(require("@babel/runtime/helpers/esm/asyncIterator.js"));
+    check(require("@babel/runtime/helpers/esm/createClass.js"));
+    check(require("@babel/runtime/helpers/esm/getPrototypeOf.js"));
+    check(require("@babel/runtime/helpers/esm/inherits.js"));
+    check(require("@babel/runtime/helpers/esm/toArray.js"));
+    check(require("@babel/runtime/helpers/esm/typeof.js"));
+  });
 });
 
 describe("Meteor packages", () => {