Update test suite

- update the packages
- move to broccoli-test-helpers

.eslintrc

@@ -7,5 +7,8 @@
     "node": true,
     "mocha": true,
     "es6": true
+  },
+  "parserOptions": {
+    "ecmaVersion": 2017
   }
 }

package.json

@@ -26,10 +26,10 @@
   },
   "devDependencies": {
     "broccoli-fixture": "^1.0.0",
+    "broccoli-test-helper": "^2.0.0",
     "chai": "^4.1.2",
-    "chai-as-promised": "^7.1.1",
-    "mocha": "^5.0.1",
-    "mocha-eslint": "^4.1.0"
+    "mocha": "^6.2.2",
+    "mocha-eslint": "^5.0.0"
   },
   "scripts": {
     "test": "mocha",

test.js

@@ -1,49 +1,72 @@
 'use strict';
 
-var MergeTrees = require('./');
-var chai = require('chai'), expect = chai.expect;
-var chaiAsPromised = require('chai-as-promised'); chai.use(chaiAsPromised);
-var Fixture = require('broccoli-fixture');
-
-function mergeFixtures(inputFixtures, options) {
-  return Fixture.build(new MergeTrees(inputFixtures.map(inputFixture), options));
-}
-
-function inputFixture(obj) {
-  return new Fixture.Node(obj);
-}
+const MergeTrees = require('./');
+const { createBuilder, createTempDir } = require('broccoli-test-helper');
+const chai = require('chai'), expect = chai.expect;
 
 describe('MergeTrees', function() {
-  it('smoke test', function() {
-    return expect(mergeFixtures([
-      {
-        foo: '1'
-      }, {
-        baz: {}
-      }
-    ])).to.eventually.deep.equal({
-      foo: '1',
-      baz: {}
+  let input, input2, output, subject;
+  beforeEach(async function () {
+    input = await createTempDir();
+    input2 = await createTempDir();
+    subject = new MergeTrees([input.path(), input2.path()]);
+    output = createBuilder(subject);
+  });
+  afterEach(async function() {
+    input.dispose();
+    input2.dispose();
+    output.dispose();
+  });
+
+  it('smoke test', async function() {
+    input.write({
+      'a.log': 'A'
+    });
+    input2.write({
+      'b.log': 'B',
+      'c.log': 'C'
+    });
+    await output.build();
+    expect(output.read()).to.deep.equal({
+      'a.log': 'A',
+      'b.log': 'B',
+      'c.log': 'C'
     });
   });
 
-  it('gives a useful error when merged trees have collisions', function () {
-    return mergeFixtures([
-      {
-        foo: 'hello',
-      }, {
-        foo: 'morehello',
-      }
-    ]).then(v => {
-      throw Error(`Should not fulfill ${v}`);
-    }, err => {
+  it('gives a useful error when merged trees have collisions', async function() {
+    input.write({
+      'a.log': 'A'
+    });
+    input2.write({
+      'a.log': 'A'
+    });
+    try {
+      await output.build();
+    } catch (err) {
       // append input nodes' names
       expect(err.message).to.contain('[BroccoliMergeTrees] error while merging the following');
-      expect(err.message).to.contain('  1.  [Fixturify]');
-      expect(err.message).to.contain('  2.  [Fixturify]');
+      expect(err.message).to.contain(`  1.  ${input.path()}`);
+      expect(err.message).to.contain(`  2.  ${input2.path()}`);
 
       // wrap existing message
-      expect(err.message).to.contain('Merge error: file foo exists in');
+      expect(err.message).to.contain('Merge error: file a.log exists in');
+    }
+  });
+  it(`doesn't error when merged trees have collisions and overwrite is set`, async function() {
+    input.write({
+      'a.log': 'A'
+    });
+    input2.write({
+      'a.log': 'B'
+    });
+    subject = new MergeTrees([input.path(), input2.path()], {
+      overwrite: true,
+    });
+    output = createBuilder(subject);
+    await output.build();
+    expect(output.read()).to.deep.equal({
+      'a.log': 'B',
     });
   });
 });