diff --git a/test/js/bun/glob/leak.test.ts b/test/js/bun/glob/leak.test.ts
index b9795bf80e70..554972464856 100644
--- a/test/js/bun/glob/leak.test.ts
+++ b/test/js/bun/glob/leak.test.ts
@@ -1,103 +1,63 @@
 import { describe, expect, test } from "bun:test";
-import { bunEnv, bunExe, isASAN, tempDir } from "harness";
+import { bunEnv, bunExe, isASAN, isDebug, isMacOS, tempDir } from "harness";
 
-// ASAN's quarantine retains freed allocations (default 256 MB) so RSS deltas
-// run far higher under bun-asan; widen the threshold there.
-const thresholdMB = isASAN ? 400 : 100;
-const timeout = 60_000;
+// Each scan()/scanSync() allocates a Box<GlobWalker> whose dominant owned
+// allocation is a PathBuffer (4 KB on Linux, 1 KB on macOS, ~96 KB on
+// Windows). When #29379 regresses, 10k iterations leak ~75-90 MB under a
+// Linux ASAN build (quarantine disabled) and 30k leak ~40 MB on macOS
+// release, versus a ~15 MB / ~7 MB noise floor with the fix in place.
+// macOS keeps 30k even under debug/ASAN: at 1 KB per iteration a 10k run
+// would only leak ~13-26 MB and slip under the 30 MB bound locally.
+const iterations = (isASAN || isDebug) && !isMacOS ? 10_000 : 30_000;
+const warmup = 500;
+const thresholdMB = 30;
 
-async function run(dir: string, code: string) {
-  await using proc = Bun.spawn({
-    cmd: [bunExe(), "--smol", "-e", code],
-    cwd: dir,
-    env: bunEnv,
-    stdio: ["inherit", "inherit", "inherit"],
-  });
-  expect(await proc.exited).toBe(0);
-}
+const cases = [
+  { name: "scanSync", pattern: "**/*", files: { "a.txt": "", "b.txt": "", "sub/c.txt": "" }, sync: true },
+  { name: "scan", pattern: "**/*", files: { "a.txt": "", "b.txt": "", "sub/c.txt": "" }, sync: false },
+  { name: "scanSync does not leak GlobWalker struct", pattern: "*.txt", files: { "a.txt": "" }, sync: true },
+  { name: "scan does not leak GlobWalker struct", pattern: "*.txt", files: { "a.txt": "" }, sync: false },
+] as const;
 
 describe("leaks", () => {
-  test.concurrent(
-    "scanSync",
-    async () => {
-      using dir = tempDir("glob-leak-scansync", { "a.txt": "", "b.txt": "", "sub/c.txt": "" });
-      await run(
-        String(dir),
-        /* ts */ `
-        const glob = new Bun.Glob("**/*");
-        for (let i = 0; i < 1000; i++) Array.from(glob.scanSync());
-        Bun.gc(true);
-        const before = process.memoryUsage.rss();
-        for (let i = 0; i < 100000; i++) Array.from(glob.scanSync());
-        Bun.gc(true);
-        const growthMB = (process.memoryUsage.rss() - before) / 1024 / 1024;
-        if (growthMB > ${thresholdMB}) throw new Error("leaked " + growthMB.toFixed(2) + "MB");
-      `,
-      );
-    },
-    timeout,
-  );
-
-  test.concurrent(
-    "scan",
-    async () => {
-      using dir = tempDir("glob-leak-scan", { "a.txt": "", "b.txt": "", "sub/c.txt": "" });
-      await run(
-        String(dir),
-        /* ts */ `
-        const glob = new Bun.Glob("**/*");
-        for (let i = 0; i < 1000; i++) await Array.fromAsync(glob.scan());
-        Bun.gc(true);
-        const before = process.memoryUsage.rss();
-        for (let i = 0; i < 100000; i++) await Array.fromAsync(glob.scan());
-        Bun.gc(true);
-        const growthMB = (process.memoryUsage.rss() - before) / 1024 / 1024;
-        if (growthMB > ${thresholdMB}) throw new Error("leaked " + growthMB.toFixed(2) + "MB");
-      `,
-      );
-    },
-    timeout,
-  );
-
-  test.concurrent(
-    "scanSync does not leak GlobWalker struct",
-    async () => {
-      using dir = tempDir("glob-struct-leak-sync", { "a.txt": "" });
-      await run(
-        String(dir),
-        /* ts */ `
-        const glob = new Bun.Glob("*.txt");
-        for (let i = 0; i < 1000; i++) Array.from(glob.scanSync());
-        Bun.gc(true);
-        const before = process.memoryUsage.rss();
-        for (let i = 0; i < 100000; i++) Array.from(glob.scanSync());
-        Bun.gc(true);
-        const growthMB = (process.memoryUsage.rss() - before) / 1024 / 1024;
-        if (growthMB > ${thresholdMB}) throw new Error("leaked " + growthMB.toFixed(2) + "MB");
-      `,
-      );
-    },
-    timeout,
-  );
-
-  test.concurrent(
-    "scan does not leak GlobWalker struct",
-    async () => {
-      using dir = tempDir("glob-struct-leak-async", { "a.txt": "" });
-      await run(
-        String(dir),
-        /* ts */ `
-        const glob = new Bun.Glob("*.txt");
-        for (let i = 0; i < 1000; i++) await Array.fromAsync(glob.scan());
-        Bun.gc(true);
-        const before = process.memoryUsage.rss();
-        for (let i = 0; i < 100000; i++) await Array.fromAsync(glob.scan());
-        Bun.gc(true);
-        const growthMB = (process.memoryUsage.rss() - before) / 1024 / 1024;
-        if (growthMB > ${thresholdMB}) throw new Error("leaked " + growthMB.toFixed(2) + "MB");
-      `,
-      );
-    },
-    timeout,
-  );
+  for (const { name, pattern, files, sync } of cases) {
+    test.concurrent(
+      name,
+      async () => {
+        using dir = tempDir(`glob-leak-${name.replace(/\W+/g, "-")}`, files);
+        const drain = sync ? "Array.from(glob.scanSync())" : "await Array.fromAsync(glob.scan())";
+        await using proc = Bun.spawn({
+          cmd: [
+            bunExe(),
+            "--smol",
+            "-e",
+            /* ts */ `
+              const glob = new Bun.Glob(${JSON.stringify(pattern)});
+              for (let i = 0; i < ${warmup}; i++) ${drain};
+              Bun.gc(true);
+              const before = process.memoryUsage.rss();
+              for (let i = 0; i < ${iterations}; i++) ${drain};
+              Bun.gc(true);
+              console.log(((process.memoryUsage.rss() - before) / 1024 / 1024).toFixed(2));
+            `,
+          ],
+          cwd: String(dir),
+          env: {
+            ...bunEnv,
+            // ASAN parks freed allocations in a quarantine (~256 MB by default)
+            // which swamps the RSS signal; disable it so one threshold holds for
+            // every build. Harmless when the binary is not ASAN-instrumented.
+            ASAN_OPTIONS: [bunEnv.ASAN_OPTIONS, "quarantine_size_mb=0"].filter(Boolean).join(":"),
+          },
+          stdout: "pipe",
+          stderr: "pipe",
+        });
+        const [stdout, stderr, exitCode] = await Promise.all([proc.stdout.text(), proc.stderr.text(), proc.exited]);
+        const growthMB = Number(stdout.trim());
+        expect({ stderr, growthMB, exitCode }).toEqual({ stderr: "", growthMB: expect.any(Number), exitCode: 0 });
+        expect(growthMB).toBeLessThan(thresholdMB);
+      },
+      60_000,
+    );
+  }
 });