test: move the shell heap snapshot out of the 1 MiB pipe test into a fixture process

test/js/bun/shell/shell-blocking-pipe.test.ts

@@ -1,23 +1,19 @@
-import { $, generateHeapSnapshot } from "bun";
+import { $ } from "bun";
 
-import { test } from "bun:test";
-import { isWindows } from "harness";
+import { expect, test } from "bun:test";
+import { bunEnv, bunExe, isWindows } from "harness";
+import { join } from "node:path";
 
-// We skip this test on Windows becasue:
+// We skip these tests on Windows because:
 // 1. Windows didn't have this problem to begin with
 // 2. We need system cat.
 test.skipIf(isWindows)("writing > send buffer size doesn't block the main thread", async () => {
   const expected = Buffer.alloc(1024 * 1024, "bun!").toString();
   const massiveComamnd = "echo " + expected + " | " + Bun.which("cat");
-  const pendingResult = $`${{
+  const result = await $`${{
     raw: massiveComamnd,
   }}`.text();
 
-  // Ensure that heap snapshot works, to excercise the memoryCost & estimated fields.
-  generateHeapSnapshot("v8");
-
-  const result = await pendingResult;
-
   if (result !== expected + "\n") {
     throw new Error("Expected " + expected + "\n but got " + result);
   }
@@ -31,3 +27,25 @@ test.skipIf(isWindows)("writing > send buffer size (with a variable) doesn't blo
     throw new Error("Expected " + expected + "\n but got " + result);
   }
 });
+
+// The snapshots are taken in a separate process; the fixture explains why.
+test.skipIf(isWindows)("heap snapshots report the script held by a pending shell command", async () => {
+  await using proc = Bun.spawn({
+    cmd: [bunExe(), join(import.meta.dir, "shell-heap-snapshot-fixture.ts")],
+    env: bunEnv,
+    stdout: "pipe",
+    stderr: "pipe",
+  });
+  const [stdout, stderr, exitCode] = await Promise.all([proc.stdout.text(), proc.stderr.text(), proc.exited]);
+
+  expect(stderr).toBe("");
+  const { scriptLength, parsedScriptBeforeRun, interpreterWhileRunning, interpreterAfterExit, stdoutMatches } =
+    JSON.parse(stdout);
+  expect(parsedScriptBeforeRun).toBeGreaterThanOrEqual(scriptLength);
+  expect(interpreterWhileRunning).toBeGreaterThanOrEqual(scriptLength);
+  expect(interpreterAfterExit).toBeLessThan(scriptLength);
+  // The second snapshot ran a full GC underneath the running command; its
+  // output must still come through intact.
+  expect(stdoutMatches).toBe(true);
+  expect(exitCode).toBe(0);
+});