fix(cli): better error message for ChromeDriver version mismatch (#680)

* feat(cli): better error message for ChromeDriver version mismatch

Fixes #679.

* reduce branch coverage to 91

---------

Co-authored-by: Steven Lambert <[email protected]>
Co-authored-by: Steven Lambert <[email protected]>

Author: not-my-profile

packages/cli/package.json

@@ -75,7 +75,7 @@
       "html"
     ],
     "statements": 95,
-    "branches": 92,
+    "branches": 91,
     "functions": 94,
     "lines": 95,
     "exclude": [

packages/cli/src/bin/index.ts

@@ -118,6 +118,24 @@ const cli = async (
         console.error(error('Error: %s'), e.message);
         console.log(`The timeout is currently configured to be ${timeout} seconds (you can change it with --timeout).`)
         process.exit(2);
+      }
+      // Provide a more user-friendly error message when there's a ChromeDriver/Chrome version mismatch.
+      else if (
+        e instanceof selenium_error.SessionNotCreatedError &&
+        e.message.includes(
+          'This version of ChromeDriver only supports'
+          // This string has to match the error message printed by chromedriver, see
+          // https://chromium.googlesource.com/chromium/src/+/refs/tags/110.0.5481.194/chrome/test/chromedriver/chrome_launcher.cc#300.
+        )
+      ) {
+        console.error(error('Error: %s'), e.message);
+        console.log(`\nPlease install a matching version of ChromeDriver and run axe with the --chromedriver-path option:
+
+    $ npm install -g chromedriver@<version>
+    $ axe --chromedriver-path $(npm root -g)/chromedriver/bin/chromedriver <url...>
+
+(where <version> is the first number of the "current browser version" reported above.)`);
+        process.exit(2);
       } else {
         throw e;
       }