test: split the Android platform test aggregation and share the scripted adb stub

src/__tests__/test-utils/mocked-binaries.ts

@@ -1,6 +1,8 @@
 import { promises as fs } from 'node:fs';
 import os from 'node:os';
 import path from 'node:path';
+import type { DeviceInfo } from '../../kernel/device.ts';
+import { ANDROID_EMULATOR } from './device-fixtures.ts';
 
 /**
  * Creates a temporary stub `adb` binary that logs all args to a file,
@@ -67,3 +69,36 @@ export async function withMockedXcrun(
     await fs.rm(tmpDir, { recursive: true, force: true });
   }
 }
+
+/**
+ * Like {@link withMockedAdb}, but with a caller-provided stub `adb` script so
+ * tests can shape per-subcommand responses instead of only recording args.
+ * The callback also receives the canonical Android emulator device fixture.
+ */
+export async function withScriptedAdb(
+  tempPrefix: string,
+  script: string,
+  run: (ctx: { argsLogPath: string; device: DeviceInfo }) => Promise<void>,
+): Promise<void> {
+  const tmpDir = await fs.mkdtemp(path.join(os.tmpdir(), tempPrefix));
+  const adbPath = path.join(tmpDir, 'adb');
+  const argsLogPath = path.join(tmpDir, 'args.log');
+  await fs.writeFile(adbPath, script, 'utf8');
+  await fs.chmod(adbPath, 0o755);
+
+  const previousPath = process.env.PATH;
+  const previousArgsFile = process.env.AGENT_DEVICE_TEST_ARGS_FILE;
+  process.env.PATH = `${tmpDir}${path.delimiter}${previousPath ?? ''}`;
+  process.env.AGENT_DEVICE_TEST_ARGS_FILE = argsLogPath;
+
+  try {
+    // Fresh copy per call: tests may tailor the device without leaking
+    // mutations into the shared fixture.
+    await run({ argsLogPath, device: { ...ANDROID_EMULATOR } });
+  } finally {
+    process.env.PATH = previousPath;
+    if (previousArgsFile === undefined) delete process.env.AGENT_DEVICE_TEST_ARGS_FILE;
+    else process.env.AGENT_DEVICE_TEST_ARGS_FILE = previousArgsFile;
+    await fs.rm(tmpDir, { recursive: true, force: true });
+  }
+}