test(config-lerna-scopes): add regression tests (#979)

* test(config-lerna-scopes): add regression tests

* test(config-lerna-scopes): do not break tests in case of lerna update

* test(config-lerna-scopes): improve tests for lerna 2 and split tests

@commitlint/config-lerna-scopes/fixtures/lerna-two/packages/a2/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "a2",
+  "version": "1.0.0"
+}

@commitlint/config-lerna-scopes/fixtures/lerna-two/packages/b2/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "b2",
+  "version": "1.0.0"
+}

@commitlint/config-lerna-scopes/index.test.js

@@ -1,5 +1,6 @@
 import {lerna} from '@commitlint/test';
 import config from '.';
+import semver from 'semver';
 
 test('exports rules key', () => {
 	expect(config).toHaveProperty('rules');
@@ -70,5 +71,27 @@ test('returns expected value for scoped lerna repository', async () => {
 test('works with lerna version < 3', async () => {
 	const {'scope-enum': fn} = config.rules;
 	const cwd = await lerna.bootstrap('lerna-two', __dirname);
-	await expect(fn({cwd})).resolves.toBeTruthy();
+	const [, , value] = await fn({cwd});
+	expect(value).toEqual(['a2', 'b2']);
+});
+
+test('uses lerna version < 3 if installed', async () => {
+	const semverLt = jest.spyOn(semver, 'lt');
+	const cwd = await lerna.bootstrap('lerna-two', __dirname);
+	const packages = await config.utils.getPackages({cwd});
+
+	expect(packages).toEqual(['a2', 'b2']);
+	expect(semverLt).toHaveBeenLastCalledWith('2.11.0', '3.0.0');
+	expect(semverLt).toHaveLastReturnedWith(true);
+});
+
+test('uses lerna version >= 3 if installed', async () => {
+	const semverLt = jest.spyOn(semver, 'lt');
+	const cwd = await lerna.bootstrap('basic', __dirname);
+
+	const packages = await config.utils.getPackages({cwd});
+
+	expect(packages).toEqual(['a', 'b']);
+	expect(semverLt).toHaveBeenLastCalledWith('3.20.2', '3.0.0');
+	expect(semverLt).toHaveLastReturnedWith(false);
 });

@packages/test/package.json

@@ -35,6 +35,7 @@
     "execa": "0.11.0",
     "fs-extra": "^8.1.0",
     "pkg-dir": "4.2.0",
+    "resolve-pkg": "2.0.0",
     "tmp": "0.1.0"
   }
 }