Generate baseline when it does exist (even without --update)

src/matchers.test.ts

@@ -73,5 +73,17 @@ describe('matchers.ts', () => {
       expect(result.pass).toBe(false);
       expect(writeFileMock).toHaveBeenCalledTimes(1);
     });
+
+    it('should return early, skipping the comparison if the latestPath is the baseline path (fresh screenshot)', () => {
+      const latestPath = 'baseline/ios/screen.png';
+
+      const result = toMatchBaseline(latestPath);
+
+      expect(result.message()).toBe(
+        'Generated a fresh baseline, skipping comparison.'
+      );
+      expect(result.pass).toBe(true);
+      expect(writeFileMock).toHaveBeenCalledTimes(0);
+    });
   });
 });

src/matchers.ts

@@ -24,6 +24,13 @@ export const toMatchBaseline = (latestPath: string) => {
     path.basename(latestPath)
   );
 
+  if (latestPath === baselinePath) {
+    return {
+      message: () => 'Generated a fresh baseline, skipping comparison.',
+      pass: true,
+    };
+  }
+
   const diffPath = path.join(
     screenshotsDir,
     'diff',

src/take-screenshot.test.ts

@@ -2,6 +2,7 @@ import execa from 'execa';
 import path from 'path';
 
 import { takeScreenshot } from './take-screenshot';
+import * as fileExistsHelpers from './utils/file-exists';
 
 const SCREENSHOT_FILENAME = 'screen';
 
@@ -75,6 +76,8 @@ describe('take-screenshot.ts', () => {
       });
 
       it('should take a screenshot', async () => {
+        jest.spyOn(fileExistsHelpers, 'fileExists').mockResolvedValueOnce(true);
+
         await takeScreenshot(SCREENSHOT_FILENAME);
 
         expect(commandMock).toHaveBeenCalledWith(
@@ -86,6 +89,19 @@ describe('take-screenshot.ts', () => {
           }
         );
       });
+
+      it('should take a screenshot - baseline does not exist', async () => {
+        await takeScreenshot(SCREENSHOT_FILENAME);
+
+        expect(commandMock).toHaveBeenCalledWith(
+          'xcrun simctl io booted screenshot screen.png',
+          {
+            cwd: path.join(process.cwd(), '.owl', 'baseline', 'ios'),
+            shell: false,
+            stdio: 'ignore',
+          }
+        );
+      });
     });
 
     describe('Android', () => {
@@ -95,6 +111,8 @@ describe('take-screenshot.ts', () => {
       });
 
       it('should take a screenshot', async () => {
+        jest.spyOn(fileExistsHelpers, 'fileExists').mockResolvedValueOnce(true);
+
         await takeScreenshot(SCREENSHOT_FILENAME);
 
         expect(commandMock).toHaveBeenCalledWith(
@@ -106,6 +124,19 @@ describe('take-screenshot.ts', () => {
           }
         );
       });
+
+      it('should take a screenshot - baseline does not exist', async () => {
+        await takeScreenshot(SCREENSHOT_FILENAME);
+
+        expect(commandMock).toHaveBeenCalledWith(
+          'adb exec-out screencap -p > screen.png',
+          {
+            cwd: path.join(process.cwd(), '.owl', 'baseline', 'android'),
+            shell: true,
+            stdio: 'ignore',
+          }
+        );
+      });
     });
   });
 });

src/take-screenshot.ts

@@ -2,8 +2,9 @@ import execa from 'execa';
 import { promises as fs } from 'fs';
 import path from 'path';
 
-import { Platform } from './cli/types';
+import { fileExists } from './utils/file-exists';
 import { Logger } from './logger';
+import { Platform } from './cli/types';
 
 /**
  * Takes a screenshot from the simulator.
@@ -22,7 +23,10 @@ export const takeScreenshot = async (filename: string): Promise<string> => {
   const screenshotsDirPath = path.join(process.cwd(), '.owl');
   await fs.mkdir(screenshotsDirPath, { recursive: true });
 
-  const DIR_NAME = updateBaseline ? 'baseline' : 'latest';
+  const baselineExist = await fileExists(
+    path.join(screenshotsDirPath, 'baseline', platform, screenshotFilename)
+  );
+  const DIR_NAME = updateBaseline || !baselineExist ? 'baseline' : 'latest';
   const cwd = path.join(screenshotsDirPath, DIR_NAME, platform);
   await fs.mkdir(cwd, { recursive: true });
 

src/utils/file-exists.ts

@@ -0,0 +1,10 @@
+import { promises as fs } from 'fs';
+
+export const fileExists = async (filePath: string): Promise<boolean> => {
+  try {
+    await fs.access(filePath);
+    return true;
+  } catch {
+    return false;
+  }
+};