diff --git a/package.json b/package.json
index e66111d..72850e6 100644
--- a/package.json
+++ b/package.json
@@ -16,7 +16,7 @@
     "compile": "npx tsc",
     "build": "npm run fix && npm run compile",
 	"prepublish": "npm run build",
-    "test": "echo \"Error: no test specified\" && exit 1"
+    "test": "node ./tests/test.js"
   },
   "devDependencies": {
     "@types/express": "^4.17.17",
diff --git a/tests/test.js b/tests/test.js
new file mode 100644
index 0000000..31576e9
--- /dev/null
+++ b/tests/test.js
@@ -0,0 +1,56 @@
+// May require `npm link`.
+const { RateLimiter } = require("../generated/ratelimiter");
+
+async function asyncRunTest(fn, ...args) {
+	try {
+		await fn(...args);
+		console.log(`✅ ${fn.name}(${args})`)
+	} catch (ex) {
+		console.log(`❌ ${fn.name}(${args})`)
+		console.error(ex);
+		process.exitCode++;
+	}
+}
+function runTest(fn, ...args) {
+	try {
+		fn(...args);
+		console.log(`✅ ${fn.name}(${args})`);
+	} catch (ex) {
+		console.log(`❌ ${fn.name}(${args})`);
+		console.error(ex);
+		process.exitCode++;
+	}
+}
+
+function test_Construct(limit) {
+	let rl = new RateLimiter(limit);
+}
+
+async function test_TaskLimit(tasks, limit) {
+	let rl = new RateLimiter(limit);
+	let p = new Array();
+	for (let idx = 0; idx < tasks; idx++) {
+		p.push(rl.queue(() => {
+			return true;
+		}));
+	}
+
+	let r = await Promise.all(p);
+	for (res of r) {
+		if (res !== true) {
+			throw new Error("Result is unexpected.");
+		}
+	}
+}
+
+(async function() {
+	process.exitCode = 0;
+	for (let limit = 1; limit <= 64; limit *= 2) {
+		runTest(test_Construct, limit);
+	}
+	for (let limit = 1; limit <= 10; limit++) {
+		for (let tasks = 1; tasks <= 64; tasks *= 2) {
+			await asyncRunTest(test_TaskLimit, tasks, limit);
+		}
+	}
+})();