First take at mocking out gemini cli responses in integration tests (#11156)

packages/cli/src/config/config.ts

@@ -68,6 +68,7 @@ export interface CliArgs {
   useSmartEdit: boolean | undefined;
   useWriteTodos: boolean | undefined;
   outputFormat: string | undefined;
+  fakeResponses: string | undefined;
 }
 
 export async function parseArguments(settings: Settings): Promise<CliArgs> {
@@ -193,6 +194,10 @@ export async function parseArguments(settings: Settings): Promise<CliArgs> {
           description: 'The format of the CLI output.',
           choices: ['text', 'json', 'stream-json'],
         })
+        .option('fake-responses', {
+          type: 'string',
+          description: 'Path to a file with fake model responses for testing.',
+        })
         .deprecateOption(
           'prompt',
           'Use the positional prompt instead. This flag will be removed in a future version.',
@@ -649,6 +654,7 @@ export async function loadCliConfig(
       settings.tools?.enableMessageBusIntegration ?? false,
     codebaseInvestigatorSettings:
       settings.experimental?.codebaseInvestigatorSettings,
+    fakeResponses: argv.fakeResponses,
     retryFetchErrors: settings.general?.retryFetchErrors ?? false,
     ptyInfo: ptyInfo?.name,
   });