[fix] Use of process.env.NODE_ENV

Corrects misspelling in a few locations and adds tests for the Platform module.

Close #2006

packages/dom-event-testing-library/src/domEnvironment.js

@@ -22,7 +22,7 @@ export function hasPointerEvent() {
 export function setPointerEvent(bool) {
   const pointerCaptureFn = (name) => (id) => {
     if (typeof id !== 'number') {
-      if (process.env.NODE_DEV !== 'production') {
+      if (process.env.NODE_ENV !== 'production') {
         console.error('A pointerId must be passed to "%s"', name);
       }
     }

packages/react-native-web/src/exports/Platform/__tests__/index-test.js

@@ -14,4 +14,22 @@ describe('apis/Platform', () => {
       ).toEqual('web');
     });
   });
+
+  describe('isTesting', () => {
+    const NODE_ENV_BACKUP = process.env.NODE_ENV;
+
+    afterEach(() => {
+      process.env.NODE_ENV = NODE_ENV_BACKUP;
+    });
+
+    test('true when NODE_ENV is "test"', () => {
+      process.env.NODE_ENV = 'test';
+      expect(Platform.isTesting).toEqual(true);
+    });
+
+    test('false when NODE_ENV is not "test"', () => {
+      process.env.NODE_ENV = 'development';
+      expect(Platform.isTesting).toEqual(false);
+    });
+  });
 });

packages/react-native-web/src/exports/Platform/index.js

@@ -12,7 +12,7 @@ const Platform = {
   OS: 'web',
   select: (obj: Object): any => ('web' in obj ? obj.web : obj.default),
   get isTesting(): boolean {
-    if (process.env.NODE_DEV === 'test') {
+    if (process.env.NODE_ENV === 'test') {
       return true;
     }
     return false;