[Fuchsia] Allows FuchsiaEmulatorCFv2 to start daemon and emulator

This change updates the FuchsiaEmulatorCFv2 to start the daemon and
emulator before executing the tests.

Meanwhile, instead of "dummy", this change uses "echo" as the dummy
command to allow
`FUCHSIA_CFV2=1 tools/test.py --progress=status
-nvm-fuchsia-release-x64 ffi`
running.

This change requires
`"fuchsia_sdk_version": "version:15.20230909.2.1",`
in DEPS to function, which isn't included due to the CFv1
implementation currently running.

Bug: #38752
Change-Id: I5011b6ff39b73955002431650d973d6adcfa6246
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/328766
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Zijie He <zijiehe@google.com>
Reviewed-by: Alexander Thomas <athom@google.com>

DEPS

@@ -646,7 +646,7 @@ Var("dart_root") + "/third_party/pkg/tar":
     "packages": [
       {
       "package": "chromium/fuchsia/test-scripts/fuchsia",
-      "version": "version:2@0d97902a72c9bc224f64630177cf95cd632604a2",
+      "version": "version:2@30ecdcc6666ac09845a2e2d4fe7d8d5714230fba",
       }
     ],
     "condition":
@@ -807,7 +807,7 @@ hooks = [
       'python3',
       'sdk/build/fuchsia/with_envs.py',
       'sdk/third_party/fuchsia/test_scripts/update_product_bundles.py',
-      'terminal.qemu-x64',
+      'terminal.x64',
     ],
     'condition': 'download_fuchsia_deps'
   },

build/fuchsia/with_envs.py

@@ -5,8 +5,18 @@
 
 import os
 import platform
+import signal
 import subprocess
 import sys
+import time
+
+sys.path.insert(
+    0,
+    os.path.abspath(
+        os.path.join(os.path.dirname(__file__),
+                     '../../third_party/fuchsia/test_scripts/test/')))
+
+from common import catch_sigterm, wait_for_sigterm
 
 
 def Main():
@@ -15,6 +25,9 @@ def Main():
     /usr/bin/env, but provides some extra functionality to dynamically set up
     the environment variables.
     """
+    # Ensures the signals can be correctly forwarded to the subprocesses.
+    catch_sigterm()
+
     os.environ['SRC_ROOT'] = os.path.abspath(
         os.path.join(os.path.dirname(__file__), os.pardir, os.pardir))
     os.environ['FUCHSIA_IMAGES_ROOT'] = os.path.join(os.environ['SRC_ROOT'],
@@ -36,7 +49,13 @@ def Main():
         os.path.join(os.environ['FUCHSIA_SDK_ROOT'], 'tools', 'x64', 'ffx'),
         'config', 'set', 'product.experimental', 'true'
     ])
-    subprocess.call(sys.argv[1:])
+
+    with subprocess.Popen(sys.argv[1:]) as proc:
+        try:
+            proc.wait()
+        except:
+            # Use terminate / SIGTERM to allow the subprocess exiting cleanly.
+            proc.terminate()
 
 
 if __name__ == '__main__':

pkg/test_runner/lib/src/fuchsia_cfv2.dart

@@ -3,6 +3,8 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
 
 import 'command.dart';
 import 'fuchsia.dart';
@@ -11,15 +13,67 @@ import 'fuchsia.dart';
 // CFv2 targets.
 // TODO(#38752): Need implementation.
 class FuchsiaEmulatorCFv2 extends FuchsiaEmulator {
-  @override
-  Future<void> publishPackage(
-      String buildDir, String mode, String arch) async {}
+  static const String ffx = "./third_party/fuchsia/sdk/linux/tools/x64/ffx";
+  static const String testScriptRoot =
+      "./third_party/fuchsia/test_scripts/test/";
+
+  Process? daemonProc;
+  Process? emuProc;
+  String? emuName;
 
   @override
-  void stop() {}
+  Future<void> publishPackage(String buildDir, String mode, String arch) async {
+    housekeeping();
+
+    assert(daemonProc == null);
+    daemonProc = await runWithOutput("isolate_daemon.py", []);
+    assert(emuProc == null);
+    emuProc = await run(
+        "start_emulator.py", ["--disable-graphics", "--target-id-only"]);
+    emuName = await emuProc!.stdout.transform(utf8.decoder).first;
+    print("+ Targeting emu name $emuName");
+  }
+
+  @override
+  void stop() {
+    // isolate_daemon.py should respect the sigterm and gracefully stop the
+    // daemon process.
+    assert(daemonProc != null);
+    daemonProc!.kill();
+    emuProc!.kill();
+
+    // In case anything goes wrong, ensure everything is cleaned up.
+    housekeeping();
+  }
 
   @override
   VMCommand getTestCommand(String mode, String arch, List<String> arguments) {
-    return VMCommand("dummy", arguments, <String, String>{});
+    return VMCommand("echo", arguments, <String, String>{});
+  }
+
+  static void housekeeping() {
+    Process.runSync(ffx, ["emu", "stop", "--all"]);
+    Process.runSync(ffx, ["repository", "server", "stop"]);
+    Process.runSync(ffx, ["daemon", "stop", "-t", "10000"]);
+  }
+
+  // Same as run, but capture the stdout and stderr.
+  static Future<Process> runWithOutput(String script, List<String> args) async {
+    return run(script, args).then((proc) {
+      proc.stdout.transform(utf8.decoder).forEach((x) {
+        print("++ [$script] stdout: $x");
+      });
+      proc.stderr.transform(utf8.decoder).forEach((x) {
+        print("++ [$script] stderr: $x");
+      });
+      return proc;
+    });
+  }
+
+  // Executes a test script inside of third_party/fuchsia/test_scripts/test/
+  // with the required environment setup and the arguments.
+  static Future<Process> run(String script, List<String> args) async {
+    return Process.start("./build/fuchsia/with_envs.py",
+        [Uri.directory(testScriptRoot).resolve(script).toString(), ...args]);
   }
 }