Add tests for react version detection

Author: alexzherdev

lib/util/version.js

@@ -9,27 +9,30 @@ const log = require('./log');
 
 let warnedForMissingVersion = false;
 
+function detectReactVersion() {
+  try {
+    const reactPath = resolve.sync('react', {basedir: process.cwd()});
+    const react = require(reactPath);
+    return react.version;
+  } catch (e) {
+    if (e.code === 'MODULE_NOT_FOUND') {
+      log('Warning: React version was set to "detect" in eslint-plugin-react settings, ' +
+        'but the "react" package is not installed. Assuming latest React version for linting.');
+      return '999.999.999';
+    }
+    throw e;
+  }
+}
+
 function getReactVersionFromContext(context) {
   let confVer = '999.999.999';
   // .eslintrc shared settings (http://eslint.org/docs/user-guide/configuring#adding-shared-settings)
   if (context.settings.react && context.settings.react.version) {
-    let settingsVer = context.settings.react.version;
-    if (settingsVer === 'detect') {
-      try {
-        const reactPath = resolve.sync('react', {basedir: process.cwd()});
-        const react = require(reactPath);
-        settingsVer = react.version;
-      } catch (e) {
-        if (e.code === 'MODULE_NOT_FOUND') {
-          log('Warning: React version was set to "detect" in eslint-plugin-react settings, ' +
-            'but the "react" package is not installed. Assuming latest React version for linting.');
-          settingsVer = '999.999.999';
-        } else {
-          throw e;
-        }
-      }
+    let settingsVersion = context.settings.react.version;
+    if (settingsVersion === 'detect') {
+      settingsVersion = detectReactVersion();
     }
-    confVer = settingsVer;
+    confVer = settingsVersion;
   } else if (!warnedForMissingVersion) {
     log('Warning: React version not specified in eslint-plugin-react settings. ' +
       'See https://github.com/yannickcr/eslint-plugin-react#configuration.');

tests/util/version.js

@@ -0,0 +1,34 @@
+/* eslint-env mocha */
+'use strict';
+
+const path = require('path');
+const assert = require('assert');
+const versionUtil = require('../../lib/util/version');
+
+describe('Version', () => {
+  const base = path.resolve(__dirname, '..', 'fixtures', 'version');
+  let cwd;
+
+  beforeEach(() => {
+    cwd = process.cwd();
+    process.chdir(base);
+  });
+
+  afterEach(() => {
+    process.chdir(cwd);
+  });
+
+  describe('Detect version', () => {
+    const context = {settings: {react: {version: 'detect'}}};
+
+    it('matches detected version', () => {
+      process.chdir('detect-version');
+      assert.equal(versionUtil.testReactVersion(context, '1.2.3'), true);
+      assert.equal(versionUtil.testReactVersion(context, '1.2.4'), false);
+    });
+
+    it('assumes latest version if react is not installed', () => {
+      assert.equal(versionUtil.testReactVersion(context, '999.999.999'), true);
+    });
+  });
+});