Reject unknown --browsertime.connectivity.engine values

lib/cli/validate.js

@@ -85,6 +85,21 @@ export function validateInput(argv) {
     return 'Error: You have a miss match between number of alias for groups and URLs.';
   }
 
+  const connectivityEngines = ['external', 'throttle', 'humble'];
+  if (
+    argv.browsertime.connectivity &&
+    argv.browsertime.connectivity.engine !== undefined &&
+    !connectivityEngines.includes(argv.browsertime.connectivity.engine)
+  ) {
+    return (
+      'Error: Unknown connectivity engine "' +
+      argv.browsertime.connectivity.engine +
+      '". Choose one of: ' +
+      connectivityEngines.join(', ') +
+      '.'
+    );
+  }
+
   if (
     argv.browsertime.connectivity &&
     argv.browsertime.connectivity.engine === 'humble' &&

test/cliTests.js

@@ -57,3 +57,20 @@ test(`CLI should silently ignore the removed summary boxes options`, async t =>
     'Should not validate the removed summary boxes options'
   );
 });
+
+test(`CLI should reject an unknown connectivity engine`, async t => {
+  let stderr = '';
+  let exitCode = 0;
+  try {
+    await runSitespeed([
+      '--browsertime.connectivity.engine',
+      'tc',
+      'https://www.sitespeed.io'
+    ]);
+  } catch (error) {
+    stderr = error.stderr;
+    exitCode = error.code;
+  }
+  t.not(exitCode, 0, 'Should exit with error code');
+  t.true(stderr.includes('Unknown connectivity engine "tc"'));
+});