test: add HTTP2-disabled diagnostic bootstrap

tests/unit/http2-diagnostic-bootstrap.test.ts

@@ -0,0 +1,16 @@
+import { readFileSync } from 'node:fs';
+import { resolve } from 'node:path';
+import { describe, expect, it } from 'vitest';
+
+describe('HTTP/1.1 diagnostic bootstrap', () => {
+  it('disables HTTP/2 before Electron startup and network initialization', () => {
+    const source = readFileSync(resolve(process.cwd(), 'electron/main/index.ts'), 'utf8');
+    const disableHttp2 = source.indexOf("app.commandLine.appendSwitch('disable-http2')");
+    const singleInstanceLock = source.indexOf('app.requestSingleInstanceLock()');
+    const ready = source.indexOf('app.whenReady()');
+
+    expect(disableHttp2).toBeGreaterThan(-1);
+    expect(disableHttp2).toBeLessThan(singleInstanceLock);
+    expect(disableHttp2).toBeLessThan(ready);
+  });
+});