Add simple test for bun --hot

test/bun.js/hot-runner-imported.js

@@ -0,0 +1,5 @@
+globalThis.importedCounter ??= 0;
+
+console.log(
+  `[${Date.now()}] [#!imported] Reloaded: ${++globalThis.importedCounter}`,
+);

test/bun.js/hot-runner.js

@@ -0,0 +1,7 @@
+import "./hot-runner-imported";
+
+globalThis.counter ??= 0;
+
+console.log(`[${Date.now()}] [#!root] Reloaded: ${++globalThis.counter}`);
+
+setTimeout(() => {}, 9999999999);

test/bun.js/hot.test.ts

@@ -0,0 +1,44 @@
+import { spawn } from "bun";
+import { expect, it } from "bun:test";
+import { bunEnv } from "bunEnv";
+import { bunExe } from "bunExe";
+import { readFileSync, unlinkSync, writeFileSync } from "fs";
+
+it("should hot reload when file is overwritten", async () => {
+  const root = import.meta.dir + "/hot-runner.js";
+  const runner = spawn({
+    cmd: [bunExe(), "--hot", "run", root],
+    env: bunEnv,
+    stdout: "pipe",
+    stderr: "inherit",
+    stdin: "ignore",
+  });
+
+  var reloadCounter = 0;
+
+  async function onReload() {
+    writeFileSync(root, readFileSync(root, "utf-8"));
+  }
+
+  await (async function () {
+    for await (const line of runner.stdout!) {
+      var str = new TextDecoder().decode(line);
+
+      if (str.includes("[#!root]")) {
+        reloadCounter++;
+
+        if (reloadCounter === 3) {
+          runner.unref();
+          runner.kill();
+          return;
+        }
+
+        expect(str).toContain(`[#!root] Reloaded: ${reloadCounter}`);
+
+        await onReload();
+      }
+    }
+  })();
+
+  expect(reloadCounter).toBe(3);
+});