test: add e2e test proving Python<->Node JSON-RPC protocol works

- Python spawns Node plugin subprocess (same as flyto-core runtime)
- Tests handshake, invoke (echo/add), context passing, error handling, ping, shutdown
- 9 tests, all passing

Author: ChesterHsu

packages/sdk/src/echo-test-plugin.ts

@@ -0,0 +1,20 @@
+// Minimal test plugin for e2e testing with flyto-core
+import { createPlugin } from "./index.js";
+
+const plugin = createPlugin({ id: "test/echo", version: "0.1.0" });
+
+plugin.step("echo", async (input) => ({
+  ok: true,
+  data: { echo: input.message, reversed: String(input.message).split("").reverse().join("") },
+}));
+
+plugin.step("add", async (input) => ({
+  ok: true,
+  data: { result: Number(input.a) + Number(input.b) },
+}));
+
+plugin.step("fail", async () => {
+  throw new Error("intentional test failure");
+});
+
+plugin.start();

tests/test_e2e_core.py

@@ -0,0 +1,167 @@
+#!/usr/bin/env python3
+"""
+End-to-end test: flyto-core Python ↔ Node.js plugin via JSON-RPC stdio.
+
+Spawns the echo test plugin as a subprocess (same as flyto-core runtime would),
+sends handshake + invoke + ping + shutdown, verifies responses.
+"""
+
+import asyncio
+import json
+import os
+import sys
+from pathlib import Path
+
+PLUGIN_JS = Path(__file__).parent.parent / "packages" / "sdk" / "dist" / "echo-test-plugin.js"
+
+async def send_recv(proc, method, params=None, msg_id=1):
+    """Send a JSON-RPC request and read the response."""
+    request = {"jsonrpc": "2.0", "method": method, "id": msg_id}
+    if params:
+        request["params"] = params
+
+    line = json.dumps(request) + "\n"
+    proc.stdin.write(line.encode())
+    await proc.stdin.drain()
+
+    raw = await asyncio.wait_for(proc.stdout.readline(), timeout=5.0)
+    return json.loads(raw.decode().strip())
+
+
+async def run_tests():
+    assert PLUGIN_JS.exists(), f"Build first: {PLUGIN_JS}"
+
+    # Spawn plugin — same as flyto-core runtime/process.py does
+    proc = await asyncio.create_subprocess_exec(
+        "node", str(PLUGIN_JS),
+        stdin=asyncio.subprocess.PIPE,
+        stdout=asyncio.subprocess.PIPE,
+        stderr=asyncio.subprocess.PIPE,
+    )
+
+    passed = 0
+    failed = 0
+
+    try:
+        # ── Test 1: Handshake ────────────────────────────
+        res = await send_recv(proc, "handshake", {
+            "protocolVersion": "0.1.0",
+            "pluginId": "test/echo",
+            "executionId": "e2e-test",
+        }, msg_id=1)
+
+        assert res["id"] == 1, f"Wrong id: {res}"
+        result = res["result"]
+        assert result["pluginVersion"] == "0.1.0", f"Wrong version: {result}"
+        assert "echo" in result["steps"], f"Missing echo step: {result}"
+        assert "add" in result["steps"], f"Missing add step: {result}"
+        print("  PASS: handshake")
+        passed += 1
+
+        # ── Test 2: Invoke echo ──────────────────────────
+        res = await send_recv(proc, "invoke", {
+            "step": "echo",
+            "input": {"message": "hello flyto"},
+        }, msg_id=2)
+
+        result = res["result"]
+        assert result["ok"] is True, f"Not ok: {result}"
+        assert result["data"]["echo"] == "hello flyto", f"Wrong echo: {result}"
+        assert result["data"]["reversed"] == "otylf olleh", f"Wrong reverse: {result}"
+        print("  PASS: invoke echo")
+        passed += 1
+
+        # ── Test 3: Invoke add ───────────────────────────
+        res = await send_recv(proc, "invoke", {
+            "step": "add",
+            "input": {"a": 17, "b": 25},
+        }, msg_id=3)
+
+        result = res["result"]
+        assert result["ok"] is True, f"Not ok: {result}"
+        assert result["data"]["result"] == 42, f"Wrong sum: {result}"
+        print("  PASS: invoke add")
+        passed += 1
+
+        # ── Test 4: Invoke with context ──────────────────
+        res = await send_recv(proc, "invoke", {
+            "step": "echo",
+            "input": {"message": "ctx-test"},
+            "context": {
+                "execution_id": "exec-999",
+                "browser_ws_endpoint": "ws://localhost:9222",
+            },
+        }, msg_id=4)
+
+        result = res["result"]
+        assert result["ok"] is True, f"Not ok: {result}"
+        assert result["data"]["echo"] == "ctx-test", f"Wrong echo: {result}"
+        print("  PASS: invoke with context")
+        passed += 1
+
+        # ── Test 5: Invoke unknown step ──────────────────
+        res = await send_recv(proc, "invoke", {
+            "step": "nonexistent",
+            "input": {},
+        }, msg_id=5)
+
+        result = res["result"]
+        assert result["ok"] is False, f"Should fail: {result}"
+        assert result["error"]["code"] == "STEP_NOT_FOUND", f"Wrong error: {result}"
+        print("  PASS: invoke unknown step returns error")
+        passed += 1
+
+        # ── Test 6: Invoke step that throws ──────────────
+        res = await send_recv(proc, "invoke", {
+            "step": "fail",
+            "input": {},
+        }, msg_id=6)
+
+        result = res["result"]
+        assert result["ok"] is False, f"Should fail: {result}"
+        assert "intentional" in result["error"]["message"], f"Wrong error msg: {result}"
+        print("  PASS: invoke throwing step returns error")
+        passed += 1
+
+        # ── Test 7: Ping ─────────────────────────────────
+        res = await send_recv(proc, "ping", msg_id=7)
+
+        result = res["result"]
+        assert result["status"] == "ok", f"Ping failed: {result}"
+        print("  PASS: ping")
+        passed += 1
+
+        # ── Test 8: Shutdown ─────────────────────────────
+        res = await send_recv(proc, "shutdown", msg_id=8)
+
+        result = res["result"]
+        assert result["status"] == "shutdown", f"Shutdown failed: {result}"
+        print("  PASS: shutdown")
+        passed += 1
+
+        # Wait for process to exit
+        await asyncio.wait_for(proc.wait(), timeout=3.0)
+        assert proc.returncode == 0, f"Non-zero exit: {proc.returncode}"
+        print("  PASS: clean exit")
+        passed += 1
+
+    except Exception as e:
+        print(f"  FAIL: {e}")
+        failed += 1
+        # Kill if still running
+        if proc.returncode is None:
+            proc.kill()
+            await proc.wait()
+
+    print(f"\n{'='*50}")
+    print(f"E2E Results: {passed} passed, {failed} failed")
+    print(f"{'='*50}")
+
+    return 1 if failed > 0 else 0
+
+
+if __name__ == "__main__":
+    print("E2E Test: Python (flyto-core) <-> Node.js (@flyto/plugin-sdk)")
+    print("="*50)
+    exit_code = asyncio.run(run_tests())
+    sys.exit(exit_code)