Add flag to update E2E snapshots (#20514)

The E2E test scripts now have a flag for updating E2E test snapshots.
The flag has been documented as well. This makes it easier to update
snapshots and raises visbility of this feature.

README.md

@@ -97,6 +97,8 @@ Single e2e tests can be run with `yarn test:e2e:single test/e2e/tests/TEST_NAME.
   --leave-running     Leaves the browser running after a test fails, along with
                       anything else that the test used (ganache, the test dapp,
                       etc.)                              [boolean] [default: false]
+  --update-snapshot   Update E2E test snapshots
+                                             [alias: -u] [boolean] [default: false]
 ```
 
 For example, to run the `account-details` tests using Chrome, with debug logging and with the browser set to remain open upon failure, you would use:

test/e2e/run-all.js

@@ -74,12 +74,27 @@ async function main() {
             description:
               'Set how many times the test should be retried upon failure.',
             type: 'number',
+          })
+          .option('update-snapshot', {
+            alias: 'u',
+            default: false,
+            description: 'Update E2E snapshots',
+            type: 'boolean',
           }),
     )
     .strict()
     .help('help');
 
-  const { browser, debug, retries, snaps, mv3, rpc, buildType } = argv;
+  const {
+    browser,
+    debug,
+    retries,
+    snaps,
+    mv3,
+    rpc,
+    buildType,
+    updateSnapshot,
+  } = argv;
 
   let testPaths;
 
@@ -130,6 +145,9 @@ async function main() {
   if (debug) {
     args.push('--debug');
   }
+  if (updateSnapshot) {
+    args.push('--update-snapshot');
+  }
 
   // For running E2Es in parallel in CI
   const currentChunkIndex = process.env.CIRCLE_NODE_INDEX ?? 0;

test/e2e/run-e2e-test.js

@@ -42,6 +42,12 @@ async function main() {
               'Leaves the browser running after a test fails, along with anything else that the test used (ganache, the test dapp, etc.)',
             type: 'boolean',
           })
+          .option('update-snapshot', {
+            alias: 'u',
+            default: false,
+            description: 'Update E2E snapshots',
+            type: 'boolean',
+          })
           .positional('e2e-test-path', {
             describe: 'The path for the E2E test to run.',
             type: 'string',
@@ -58,6 +64,7 @@ async function main() {
     retries,
     retryUntilFailure,
     leaveRunning,
+    updateSnapshot,
   } = argv;
 
   if (!browser) {
@@ -103,6 +110,10 @@ async function main() {
     exit = '--no-exit';
   }
 
+  if (updateSnapshot) {
+    process.env.UPDATE_SNAPSHOTS = 'true';
+  }
+
   const configFile = path.join(__dirname, '.mocharc.js');
   const extraArgs = process.env.E2E_ARGS?.split(' ') || [];