Fail snapshot test at done()

Author: compulim

packages/test/harness/src/host/common/host/done.js

@@ -35,5 +35,12 @@ module.exports = (webDriver, resolve) =>
       expect(filteredErrors).toHaveLength(0);
     }
 
+    // All `toMatchImageSnapshot()` will pass so we can generate multiple diffs on a single run.
+    // But always fail in `done()` when one of the snapshot test failed.
+    // See /packages/test/harness/src/host/common/host/snapshot.js
+    if ('__snapshotfail__' in webDriver) {
+      throw new Error(webDriver.__snapshotfail__ || 'At least one of the snapshot test failed');
+    }
+
     resolve();
   };

packages/test/harness/src/host/common/host/snapshot.js

@@ -12,18 +12,31 @@ module.exports = webDriver =>
 
     const screenshot = await takeStabilizedScreenshot(webDriver);
 
-    expect(screenshot).toMatchImageSnapshot(
-      mode === 'local'
-        ? {
-            customDiffDir: testRoot,
-            customSnapshotIdentifier: ({ counter, testPath }) => `${relative(testRoot, testPath)}.snap-${counter}`,
-            customSnapshotsDir: testRoot
+    try {
+      expect(screenshot).toMatchImageSnapshot(
+        mode === 'local'
+          ? {
+              customDiffDir: testRoot,
+              customSnapshotIdentifier: ({ counter, testPath }) => `${relative(testRoot, testPath)}.snap-${counter}`,
+              customSnapshotsDir: testRoot
+            }
+          : {
+              // jest-image-snapshot does not support <rootDir>.
+              customSnapshotsDir: join(__dirname, '../../../../../../../__tests__/__image_snapshots__/html/')
+            }
+      );
+    } catch (error) {
+      // Hidden variable to fail the test.
+      if (!('__snapshotfail__' in webDriver)) {
+        Object.defineProperty(webDriver, '__snapshotfail__', {
+          configurable: false,
+          enumerable: true,
+          get() {
+            return error.message;
           }
-        : {
-            // jest-image-snapshot does not support <rootDir>.
-            customSnapshotsDir: join(__dirname, '../../../../../../../__tests__/__image_snapshots__/html/')
-          }
-    );
+        });
+      }
+    }
 
     if (!options?.skipCheckAccessibility) {
       await checkAccessibilty(webDriver)();