8 files changed, 123 insertions, 2 deletions
diff --git a/test/js/web/timers/process-setImmediate-fixture.js b/test/js/web/timers/process-setImmediate-fixture.js
new file mode 100644
index 000000000..6ffd91c8d
--- /dev/null
+++ b/test/js/web/timers/process-setImmediate-fixture.js
@@ -0,0 +1,9 @@
+setImmediate(() => {
+  console.log("setImmediate");
+  return {
+    a: 1,
+    b: 2,
+    c: 3,
+    d: 4,
+  };
+});
diff --git a/test/js/web/timers/setImmediate.test.js b/test/js/web/timers/setImmediate.test.js
index 9cd6fa1c9..d00224e0f 100644
--- a/test/js/web/timers/setImmediate.test.js
+++ b/test/js/web/timers/setImmediate.test.js
@@ -1,4 +1,6 @@
 import { it, expect } from "bun:test";
+import { bunExe, bunEnv } from "harness";
+import path from "path";
 
 it("setImmediate", async () => {
   var lastID = -1;
@@ -45,3 +47,28 @@ it("clearImmediate", async () => {
   });
   expect(called).toBe(false);
 });
+
+it("setImmediate should not keep the process alive forever", async () => {
+  let process = null;
+  const success = async () => {
+    process = Bun.spawn({
+      cmd: [bunExe(), "run", path.join(import.meta.dir, "process-setImmediate-fixture.js")],
+      stdout: "ignore",
+      env: {
+        ...bunEnv,
+        NODE_ENV: undefined,
+      },
+    });
+    await process.exited;
+    process = null;
+    return true;
+  };
+
+  const fail = async () => {
+    await Bun.sleep(500);
+    process?.kill();
+    return false;
+  };
+
+  expect(await Promise.race([success(), fail()])).toBe(true);
+});
diff --git a/test/js/web/timers/setTimeout-unref-fixture-2.js b/test/js/web/timers/setTimeout-unref-fixture-2.js
new file mode 100644
index 000000000..6a78f13cd
--- /dev/null
+++ b/test/js/web/timers/setTimeout-unref-fixture-2.js
@@ -0,0 +1,9 @@
+setTimeout(() => {
+  console.log("TEST FAILED!");
+}, 100)
+  .ref()
+  .unref();
+
+setTimeout(() => {
+  // this one should always run
+}, 1);
diff --git a/test/js/web/timers/setTimeout-unref-fixture-3.js b/test/js/web/timers/setTimeout-unref-fixture-3.js
new file mode 100644
index 000000000..41808f5fc
--- /dev/null
+++ b/test/js/web/timers/setTimeout-unref-fixture-3.js
@@ -0,0 +1,7 @@
+setTimeout(() => {
+  setTimeout(() => {}, 999_999);
+}, 100).unref();
+
+setTimeout(() => {
+  // this one should always run
+}, 1);
diff --git a/test/js/web/timers/setTimeout-unref-fixture-4.js b/test/js/web/timers/setTimeout-unref-fixture-4.js
new file mode 100644
index 000000000..9968f3b36
--- /dev/null
+++ b/test/js/web/timers/setTimeout-unref-fixture-4.js
@@ -0,0 +1,5 @@
+setTimeout(() => {
+  console.log("TEST PASSED!");
+}, 1)
+  .unref()
+  .ref();
diff --git a/test/js/web/timers/setTimeout-unref-fixture-5.js b/test/js/web/timers/setTimeout-unref-fixture-5.js
new file mode 100644
index 000000000..e5caa1be4
--- /dev/null
+++ b/test/js/web/timers/setTimeout-unref-fixture-5.js
@@ -0,0 +1,5 @@
+setTimeout(() => {
+  console.log("TEST FAILED!");
+}, 100)
+  .ref()
+  .unref();
diff --git a/test/js/web/timers/setTimeout-unref-fixture.js b/test/js/web/timers/setTimeout-unref-fixture.js
new file mode 100644
index 000000000..97a0f78a2
--- /dev/null
+++ b/test/js/web/timers/setTimeout-unref-fixture.js
@@ -0,0 +1,12 @@
+const timer = setTimeout(() => {}, 999_999_999);
+if (timer.unref() !== timer) throw new Error("Expected timer.unref() === timer");
+
+var ranCount = 0;
+const going2Refresh = setTimeout(() => {
+  if (ranCount < 1) going2Refresh.refresh();
+  ranCount++;
+
+  if (ranCount === 2) {
+    console.log("SUCCESS");
+  }
+}, 1);
diff --git a/test/js/web/timers/setTimeout.test.js b/test/js/web/timers/setTimeout.test.js
index dbe89dea8..eef6bbae0 100644
--- a/test/js/web/timers/setTimeout.test.js
+++ b/test/js/web/timers/setTimeout.test.js
@@ -1,5 +1,7 @@
+import { spawnSync } from "bun";
 import { it, expect } from "bun:test";
-
+import { bunEnv, bunExe } from "harness";
+import path from "node:path";
 it("setTimeout", async () => {
   var lastID = -1;
   const result = await new Promise((resolve, reject) => {
@@ -172,11 +174,56 @@ it.skip("order of setTimeouts", done => {
   Promise.resolve().then(maybeDone(() => nums.push(1)));
 });
 
+it("setTimeout -> refresh", () => {
+  const { exitCode, stdout } = spawnSync({
+    cmd: [bunExe(), path.join(import.meta.dir, "setTimeout-unref-fixture.js")],
+    env: bunEnv,
+  });
+  expect(exitCode).toBe(0);
+  expect(stdout.toString()).toBe("SUCCESS\n");
+});
+
+it("setTimeout -> unref -> ref works", () => {
+  const { exitCode, stdout } = spawnSync({
+    cmd: [bunExe(), path.join(import.meta.dir, "setTimeout-unref-fixture-4.js")],
+    env: bunEnv,
+  });
+  expect(exitCode).toBe(0);
+  expect(stdout.toString()).toBe("TEST PASSED!\n");
+});
+
+it("setTimeout -> ref -> unref works, even if there is another timer", () => {
+  const { exitCode, stdout } = spawnSync({
+    cmd: [bunExe(), path.join(import.meta.dir, "setTimeout-unref-fixture-2.js")],
+    env: bunEnv,
+  });
+  expect(exitCode).toBe(0);
+  expect(stdout.toString()).toBe("");
+});
+
+it("setTimeout -> ref -> unref works", () => {
+  const { exitCode, stdout } = spawnSync({
+    cmd: [bunExe(), path.join(import.meta.dir, "setTimeout-unref-fixture-5.js")],
+    env: bunEnv,
+  });
+  expect(exitCode).toBe(0);
+  expect(stdout.toString()).toBe("");
+});
+
+it("setTimeout -> unref doesn't keep event loop alive forever", () => {
+  const { exitCode, stdout } = spawnSync({
+    cmd: [bunExe(), path.join(import.meta.dir, "setTimeout-unref-fixture-3.js")],
+    env: bunEnv,
+  });
+  expect(exitCode).toBe(0);
+  expect(stdout.toString()).toBe("");
+});
+
 it("setTimeout should refresh N times", done => {
   let count = 0;
   let timer = setTimeout(() => {
     count++;
-    timer.refresh();
+    expect(timer.refresh()).toBe(timer);
   }, 50);
 
   setTimeout(() => {