feat(rollup-config-pectin): Use advanced multi-config for better ESM …

…output

packages/rollup-config-pectin/.babelrc

@@ -0,0 +1,5 @@
+{
+    "presets": [
+        "@babel/preset-env"
+    ]
+}

packages/rollup-config-pectin/lib/rollup-config-pectin.js

@@ -1,3 +1,10 @@
 'use strict';
 
-module.exports = require('@pectin/core')('package.json');
+const path = require('path');
+const pectin = require('@pectin/core');
+
+const cwd = process.cwd();
+// eslint-disable-next-line zillow/import/no-dynamic-require
+const pkg = require(path.resolve(cwd, 'package.json'));
+
+module.exports = pectin.createMultiConfig(pkg, { cwd });

packages/rollup-config-pectin/test/rollup-config-pectin.test.js

@@ -1,13 +1,49 @@
 'use strict';
 
-const pectinCore = require('@pectin/core');
+const path = require('path');
 
-jest.mock('@pectin/core', () => jest.fn(() => 'I am tested elsewhere!'));
+const REPO_ROOT = path.resolve(__dirname, '../../..');
+const CONFIG_FILE = path.resolve(__dirname, '../lib/rollup-config-pectin');
+
+expect.addSnapshotSerializer({
+    test(val) {
+        return typeof val === 'string' && val.indexOf(REPO_ROOT) > -1;
+    },
+    serialize(val, config, indentation, depth) {
+        const str = val.replace(REPO_ROOT, '<REPO_ROOT>');
+
+        // top-level strings don't need quotes, but nested ones do (object properties, etc)
+        return depth ? `"${str}"` : str;
+    },
+});
 
 describe('rollup-config-pectin', () => {
-    it('exports rollup config from cwd', () => {
-        // eslint-disable-next-line global-require
-        expect(require('../')).toBe('I am tested elsewhere!');
-        expect(pectinCore).lastCalledWith('package.json');
+    it('exports rollup config from cwd', async () => {
+        // config file expects to operate in CWD
+        process.chdir(path.resolve(__dirname, '..'));
+
+        // eslint-disable-next-line global-require, zillow/import/no-dynamic-require
+        const config = await require(CONFIG_FILE);
+
+        expect(config).toHaveLength(1);
+        expect(config[0]).toMatchInlineSnapshot(
+            {
+                plugins: expect.any(Array),
+            },
+            `
+Object {
+  "experimentalCodeSplitting": false,
+  "input": "<REPO_ROOT>/packages/rollup-config-pectin/src/rollup-config-pectin.js",
+  "output": Array [
+    Object {
+      "exports": "auto",
+      "file": "<REPO_ROOT>/packages/rollup-config-pectin/lib/rollup-config-pectin.js",
+      "format": "cjs",
+    },
+  ],
+  "plugins": Any<Array>,
+}
+`
+        );
     });
 });