feat: US-085 - Add cross-runtime terminal tests: node -e and python3 -c from brush-shell

Author: NathanFlurry

packages/kernel/src/kernel.ts

@@ -400,6 +400,17 @@ class KernelImpl implements Kernel {
 		// Register PID ownership before driver.spawn() so the driver can use it
 		this.driverPids.get(driver.name)?.add(pid);
 
+		// Cross-runtime spawn: parent driver must also track child PID so
+		// it can waitpid/kill/interact with the child process
+		if (callerPid !== undefined) {
+			for (const [name, pids] of this.driverPids) {
+				if (name !== driver.name && pids.has(callerPid)) {
+					pids.add(pid);
+					break;
+				}
+			}
+		}
+
 		// Create FD table — wire pipe FDs when overrides are provided
 		const table = this.createChildFDTable(pid, options, callerPid);
 
@@ -411,15 +422,43 @@ class KernelImpl implements Kernel {
 		const stdoutBuf: Uint8Array[] = [];
 		const stderrBuf: Uint8Array[] = [];
 
+		// Resolve output callbacks: when a child inherits non-piped stdio from
+		// a parent, forward output to the parent's DriverProcess callbacks so
+		// cross-runtime child output reaches the top-level collector.
+		let stdoutCb: ((data: Uint8Array) => void) | undefined;
+		let stderrCb: ((data: Uint8Array) => void) | undefined;
+		if (!stdoutPiped) {
+			if (options?.onStdout) {
+				stdoutCb = options.onStdout;
+			} else if (callerPid !== undefined) {
+				const parent = this.processTable.get(callerPid);
+				if (parent?.driverProcess.onStdout) {
+					stdoutCb = parent.driverProcess.onStdout;
+				}
+			}
+			if (!stdoutCb) stdoutCb = (data) => stdoutBuf.push(data);
+		}
+		if (!stderrPiped) {
+			if (options?.onStderr) {
+				stderrCb = options.onStderr;
+			} else if (callerPid !== undefined) {
+				const parent = this.processTable.get(callerPid);
+				if (parent?.driverProcess.onStderr) {
+					stderrCb = parent.driverProcess.onStderr;
+				}
+			}
+			if (!stderrCb) stderrCb = (data) => stderrBuf.push(data);
+		}
+
 		// Build process context with pre-wired callbacks
 		const ctx: ProcessContext = {
 			pid,
 			ppid: callerPid ?? 0,
 			env: { ...this.env, ...options?.env },
 			cwd: options?.cwd ?? this.cwd,
 			fds: { stdin: 0, stdout: 1, stderr: 2 },
-			onStdout: stdoutPiped ? undefined : (data) => stdoutBuf.push(data),
-			onStderr: stderrPiped ? undefined : (data) => stderrBuf.push(data),
+			onStdout: stdoutCb,
+			onStderr: stderrCb,
 		};
 
 		// Spawn via driver

packages/secure-exec/tests/kernel/cross-runtime-terminal.test.ts

@@ -0,0 +1,113 @@
+/**
+ * Cross-runtime terminal tests — node -e and python3 -c from brush-shell.
+ *
+ * Mounts WasmVM + Node + Python into the same kernel and verifies
+ * interactive output through TerminalHarness.
+ *
+ * Gated: WasmVM binary required for all tests, Pyodide import for Python.
+ */
+
+import { describe, it, expect, afterEach } from 'vitest';
+import { TerminalHarness } from '../../../kernel/test/terminal-harness.ts';
+import {
+  createIntegrationKernel,
+  skipUnlessWasmBuilt,
+  type IntegrationKernelResult,
+} from './helpers.ts';
+
+/** brush-shell interactive prompt. */
+const PROMPT = 'sh-0.4$ ';
+
+const wasmSkip = skipUnlessWasmBuilt();
+
+// Dynamic import check — require.resolve finds pyodide but ESM import may fail
+let pyodideImportable = false;
+try {
+  await import('pyodide');
+  pyodideImportable = true;
+} catch {
+  // pyodide can't be imported as ESM — skip Python tests
+}
+
+// ---------------------------------------------------------------------------
+// Node cross-runtime terminal tests
+// ---------------------------------------------------------------------------
+
+describe.skipIf(wasmSkip)('cross-runtime terminal: node', () => {
+  let harness: TerminalHarness;
+  let ctx: IntegrationKernelResult;
+
+  afterEach(async () => {
+    await harness?.dispose();
+    await ctx?.dispose();
+  });
+
+  it('node -e "console.log(42)" → 42 appears on screen', async () => {
+    ctx = await createIntegrationKernel({ runtimes: ['wasmvm', 'node'] });
+    harness = new TerminalHarness(ctx.kernel);
+
+    await harness.waitFor(PROMPT);
+    await harness.type('node -e "console.log(42)"\n');
+    await harness.waitFor(PROMPT, 2, 10_000);
+
+    const screen = harness.screenshotTrimmed();
+    expect(screen).toContain('42');
+    // Verify prompt returned
+    const lines = screen.split('\n');
+    expect(lines[lines.length - 1]).toBe(PROMPT);
+  }, 15_000);
+
+  it('^C during node -e — shell survives and prompt returns', async () => {
+    ctx = await createIntegrationKernel({ runtimes: ['wasmvm', 'node'] });
+    harness = new TerminalHarness(ctx.kernel);
+
+    await harness.waitFor(PROMPT);
+    // Start a long-running node process
+    harness.shell.write('node -e "setTimeout(() => {}, 60000)"\n');
+
+    // Give it a moment to start, then send ^C
+    await new Promise((r) => setTimeout(r, 500));
+    harness.shell.write('\x03');
+
+    // Wait for prompt to return
+    await harness.waitFor(PROMPT, 2, 10_000);
+
+    // Verify shell is still alive — type another command
+    await harness.type('echo alive\n');
+    await harness.waitFor('alive', 1, 5_000);
+
+    const screen = harness.screenshotTrimmed();
+    expect(screen).toContain('alive');
+  }, 20_000);
+});
+
+// ---------------------------------------------------------------------------
+// Python cross-runtime terminal tests
+// ---------------------------------------------------------------------------
+
+describe.skipIf(wasmSkip || !pyodideImportable)('cross-runtime terminal: python', () => {
+  let harness: TerminalHarness;
+  let ctx: IntegrationKernelResult;
+
+  afterEach(async () => {
+    await harness?.dispose();
+    await ctx?.dispose();
+  });
+
+  it('python3 -c "print(99)" → 99 appears on screen', async () => {
+    ctx = await createIntegrationKernel({
+      runtimes: ['wasmvm', 'python'],
+    });
+    harness = new TerminalHarness(ctx.kernel);
+
+    await harness.waitFor(PROMPT);
+    await harness.type('python3 -c "print(99)"\n');
+    await harness.waitFor(PROMPT, 2, 30_000);
+
+    const screen = harness.screenshotTrimmed();
+    expect(screen).toContain('99');
+    // Verify prompt returned
+    const lines = screen.split('\n');
+    expect(lines[lines.length - 1]).toBe(PROMPT);
+  }, 45_000);
+});