Add test demonstrating the config merge behavior that would fail with the bug

Co-authored-by: mrlubos <[email protected]>

Author: Copilot

packages/openapi-ts/src/__tests__/interactive.test.ts

@@ -1,6 +1,7 @@
 import { describe, expect, it } from 'vitest';
 
 import { initConfigs } from '../config/init';
+import { mergeConfigs } from '../config/merge';
 
 describe('interactive config', () => {
   it('should default to false when not provided', async () => {
@@ -31,4 +32,38 @@ describe('interactive config', () => {
 
     expect(result.results[0].config.interactive).toBe(false);
   });
+
+  it('should allow file config to set interactive when CLI does not provide it', () => {
+    // This simulates what happens when:
+    // 1. User has a config file with interactive: false
+    // 2. CLI doesn't provide interactive (undefined)
+    // 3. The bug was: bin script would set interactive = isInteractive (true in TTY)
+
+    const fileConfig = {
+      input: 'test.json',
+      interactive: false,
+      output: './test',
+    };
+
+    // CLI config without interactive (correct behavior after fix)
+    const cliConfigWithoutInteractive = {
+      input: 'test.json',
+      output: './test',
+    };
+
+    // CLI config with interactive set to true (simulating the bug)
+    const cliConfigWithInteractiveBug = {
+      input: 'test.json',
+      interactive: true,
+      output: './test', // Bug: bin script was setting this even when user didn't provide it
+    };
+
+    // After fix: file config's interactive should be preserved
+    const mergedCorrect = mergeConfigs(fileConfig, cliConfigWithoutInteractive);
+    expect(mergedCorrect.interactive).toBe(false);
+
+    // Before fix: CLI's auto-detected interactive would override file config
+    const mergedWithBug = mergeConfigs(fileConfig, cliConfigWithInteractiveBug);
+    expect(mergedWithBug.interactive).toBe(true); // This was the bug - it overrode the file config
+  });
 });