test: fixing test for node 7 / 8

package.json

@@ -19,6 +19,7 @@
     "test": "{lib,test}/**/*.js"
   },
   "devDependencies": {
+    "assert-rejects": "^1.0.0",
     "auto-changelog": "^1.8.0",
     "c8": "^3.2.0",
     "coveralls": "^3.0.2",

test/installer.js

@@ -11,6 +11,9 @@ const {
 } = require('../lib/installer');
 const { COMPLETION_DIR } = require('../lib/constants');
 
+// For node 7 / 8
+assert.rejects = require('./utils/rejects');
+
 const readFile = promisify(fs.readFile);
 
 describe('installer', () => {

test/tabtab-install.js

@@ -10,6 +10,9 @@ const { COMPLETION_DIR } = require('../lib/constants');
 
 const readFile = promisify(fs.readFile);
 
+// For node 7 / 8
+assert.rejects = require('./utils/rejects');
+
 // inquirer-test needs a little bit more time, or my setup
 const TIMEOUT = 500;
 const { ENTER } = run;
@@ -19,18 +22,18 @@ describe('tabtab.install()', () => {
     assert.equal(typeof tabtab.install, 'function');
   });
 
-  it('throws on missing options', async () => {
+  it('rejects on missing options', async () => {
     await assert.rejects(async () => tabtab.install(), TypeError);
   });
 
-  it('throws on missing name options', async () => {
+  it('rejects on missing name options', async () => {
     await assert.rejects(
       async () => tabtab.install({}),
       /options\.name is required/
     );
   });
 
-  it('throws on missing completer options', async () => {
+  it('rejects on missing completer options', async () => {
     await assert.rejects(
       async () => tabtab.install({ name: 'foo' }),
       /options\.completer is required/

test/utils/rejects.js

@@ -0,0 +1,27 @@
+// For node 7 / 8
+module.exports = async (promise, error, message = '') => {
+  let toThrow;
+  await promise().catch(err => {
+    if (error instanceof RegExp) {
+      const ok = error.test(err.message);
+      if (!ok) {
+        toThrow = new Error(
+          `AssertionError: ${error} is not validated
+          ${message}`
+        );
+      }
+    } else {
+      const ok = err instanceof error;
+      if (!ok) {
+        toThrow = new Error(
+          `AssertionError: ${err.name} is not an instanceof ${error.name}
+          ${message}`
+        );
+      }
+    }
+  });
+
+  if (toThrow) {
+    throw toThrow;
+  }
+};