metro-bundler/src/ModuleGraph: test image asset transform

Reviewed By: davidaurelio

Differential Revision: D6039836

fbshipit-source-id: 0fc022b72892f8a7064482f63e19b9fa5a3d5b00

packages/metro-bundler/src/ModuleGraph/worker/__tests__/__snapshots__/transform-module-test.js.snap

@@ -1,3 +1,39 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`transforming JS modules: assets extract image sizes, platform, scale 1`] = `
+Object {
+  "details": Object {
+    "assetPath": "foo.png",
+    "contentBase64": "eyJfX3NpemUiOnsid2lkdGgiOjMwLCJoZWlnaHQiOjIwfX0=",
+    "contentType": "png",
+    "filePath": "foo.png",
+    "physicalSize": Object {
+      "height": 20,
+      "width": 30,
+    },
+    "platform": null,
+    "scale": 1,
+  },
+  "type": "asset",
+}
+`;
+
+exports[`transforming JS modules: assets extract image sizes, platform, scale 2`] = `
+Object {
+  "details": Object {
+    "assetPath": "foo.png",
+    "contentBase64": "eyJfX3NpemUiOnsid2lkdGgiOjMwLCJoZWlnaHQiOjIwfX0=",
+    "contentType": "png",
+    "filePath": "foo@2x.ios.png",
+    "physicalSize": Object {
+      "height": 20,
+      "width": 30,
+    },
+    "platform": "ios",
+    "scale": 2,
+  },
+  "type": "asset",
+}
+`;
+
 exports[`transforming JS modules: assets throws on empty images 1`] = `"Image asset \`foo.png\` cannot be an empty file."`;

packages/metro-bundler/src/ModuleGraph/worker/__tests__/transform-module-test.js

@@ -21,6 +21,10 @@ const {parse} = require('babylon');
 const generate = require('babel-generator').default;
 const {traverse} = require('babel-core');
 
+jest.mock('image-size', () => buffer => {
+  return JSON.parse(buffer.toString('utf8')).__size;
+});
+
 describe('transforming JS modules:', () => {
   const filename = 'arbitrary';
 
@@ -212,6 +216,18 @@ describe('transforming JS modules:', () => {
   });
 
   describe('assets', () => {
+    it('extract image sizes, platform, scale', () => {
+      const image = {__size: {width: 30, height: 20}};
+      ['foo.png', 'foo@2x.ios.png'].forEach(filePath => {
+        expect(
+          transformModule(new Buffer(JSON.stringify(image), 'utf8'), {
+            ...options(),
+            filename: filePath,
+          }),
+        ).toMatchSnapshot();
+      });
+    });
+
     it('throws on empty images', () => {
       expect(() =>
         transformModule(new Buffer(0), {...options(), filename: 'foo.png'}),