diff --git a/server/client.test.ts b/server/client.test.ts
index cfbf96a..160f09d 100644
--- a/server/client.test.ts
+++ b/server/client.test.ts
@@ -1,15 +1,58 @@
 import { assertEquals } from "jsr:@std/assert";
 import { createSession } from "#/server/handler.ts";
 import handler from "./handler.ts";
-import { close, connect, flush, href, setup } from "./testSetup.ts";
+import { close, connect, flush, hostname, port, setup } from "./testSetup.ts";
+
+const href = `ws://${hostname}:${port}`;
 
 Deno.test(
-	"test",
+	"needs upgrade header",
+	setup(async () => {
+		const res = await fetch(`http://${hostname}:${port}`);
+		assertEquals(res.status, 426);
+		assertEquals(res.statusText, "Upgrade Required");
+	}, handler),
+);
+
+Deno.test(
+	"needs a session parameter",
+	setup(async () => {
+		const res = await connect(href).catch((reason) => {
+			return reason;
+		});
+
+		assertEquals(
+			res.message,
+			"NetworkError: failed to connect to WebSocket: Invalid status code: 400",
+		);
+	}, handler),
+);
+
+Deno.test(
+	"needs an existing session",
+	setup(async () => {
+		const res = await connect(`${href}?sessionId=DOES_NOT_EXISTS`).catch(
+			(reason) => {
+				return reason;
+			},
+		);
+
+		assertEquals(
+			res.message,
+			"NetworkError: failed to connect to WebSocket: Invalid status code: 401",
+		);
+	}, handler),
+);
+
+Deno.test(
+	"connects to an existing session",
 	setup(async () => {
 		const sessionId = createSession();
 		const [s1, m1] = await connect(`${href}?sessionId=${sessionId}`);
+
 		await flush();
 		assertEquals(m1, []);
+
 		await close(s1);
 	}, handler),
 );
diff --git a/server/handler.ts b/server/handler.ts
index 8c5dfaa..d43999f 100644
--- a/server/handler.ts
+++ b/server/handler.ts
@@ -1,7 +1,5 @@
 import { STATUS_CODE, STATUS_TEXT, type StatusCode } from "jsr:@std/http";
 
-const ALLOWED_ORIGIN = "http://0.0.0.0:8042";
-
 type Session = {
 	id: string;
 	connId: number;
@@ -68,7 +66,7 @@ export default function (request: Request): Response {
 
 	const url = new URL(request.url);
 	const sessionId = url.searchParams.get("sessionId");
-	if (url.origin !== ALLOWED_ORIGIN || sessionId === null) {
+	if (sessionId === null) {
 		return createResponse(STATUS_CODE.BadRequest);
 	}
 
diff --git a/server/testSetup.ts b/server/testSetup.ts
index 8c11808..0c1f38b 100644
--- a/server/testSetup.ts
+++ b/server/testSetup.ts
@@ -2,7 +2,6 @@ import { startServer } from "./server.ts";
 
 export const hostname = "0.0.0.0";
 export const port = 8042;
-export const href = `ws://${hostname}:${port}`;
 
 export function setup(
 	fn: (ctx: Deno.TestContext) => Promise<void>,