diff --git a/backend/Cargo.toml b/backend/Cargo.toml
index b44b5ad..cd70bc0 100644
--- a/backend/Cargo.toml
+++ b/backend/Cargo.toml
@@ -20,4 +20,7 @@ base64 = "0.13.0"
 
 [dependencies.rocket_sync_db_pools]
 version = "0.1.0-rc.1"
-features = ["diesel_postgres_pool"]
\ No newline at end of file
+features = ["diesel_postgres_pool"]
+
+[dev-dependencies]
+parking_lot = "0.11"
\ No newline at end of file
diff --git a/backend/migrations/2021-12-13-145111_users/down.sql b/backend/migrations/2021-12-13-145111_users/down.sql
index 441087a..49285a1 100644
--- a/backend/migrations/2021-12-13-145111_users/down.sql
+++ b/backend/migrations/2021-12-13-145111_users/down.sql
@@ -1 +1,2 @@
+DROP INDEX users_username_index
 DROP TABLE users;
\ No newline at end of file
diff --git a/backend/migrations/2021-12-13-145111_users/up.sql b/backend/migrations/2021-12-13-145111_users/up.sql
index 6ec7e01..f35e718 100644
--- a/backend/migrations/2021-12-13-145111_users/up.sql
+++ b/backend/migrations/2021-12-13-145111_users/up.sql
@@ -3,4 +3,6 @@ CREATE TABLE users(
     username VARCHAR(52) NOT NULL,
     password_salt BYTEA NOT NULL,
     password_hash BYTEA NOT NULL
-);
\ No newline at end of file
+);
+
+CREATE UNIQUE INDEX users_username_index ON users(username);
\ No newline at end of file
diff --git a/backend/src/lib.rs b/backend/src/lib.rs
new file mode 100644
index 0000000..0a21850
--- /dev/null
+++ b/backend/src/lib.rs
@@ -0,0 +1,35 @@
+#![feature(proc_macro_hygiene, decl_macro)]
+
+use rocket::{Build, Rocket};
+use rocket_sync_db_pools::database;
+
+#[macro_use]
+extern crate rocket;
+#[macro_use]
+extern crate diesel;
+
+mod db;
+mod routes;
+mod schema;
+
+#[database("postgresql_database")]
+pub struct DbConn(diesel::PgConnection);
+
+#[get("/")]
+fn index() -> &'static str {
+    "Hello, world!"
+}
+
+pub fn rocket() -> Rocket<Build> {
+    rocket::build()
+        .mount(
+            "/",
+            routes![
+                index,
+                routes::users::register,
+                routes::users::login,
+                routes::users::current_user,
+            ],
+        )
+        .attach(DbConn::fairing())
+}
diff --git a/backend/src/main.rs b/backend/src/main.rs
index 6ee54ec..65be48d 100644
--- a/backend/src/main.rs
+++ b/backend/src/main.rs
@@ -1,36 +1,8 @@
-#![feature(proc_macro_hygiene, decl_macro)]
-
-use rocket::{Build, Rocket};
-use rocket_sync_db_pools::database;
-
 #[macro_use]
 extern crate rocket;
-#[macro_use]
-extern crate diesel;
-
-mod db;
-mod routes;
-mod schema;
-
-#[database("postgresql_database")]
-pub struct DbConn(diesel::PgConnection);
-
-#[get("/")]
-fn index() -> &'static str {
-    "Hello, world!"
-}
+extern crate mozaic4_backend;
 
 #[launch]
-fn rocket() -> Rocket<Build> {
-    rocket::build()
-        .mount(
-            "/",
-            routes![
-                index,
-                routes::users::register,
-                routes::users::login,
-                routes::users::current_user,
-            ],
-        )
-        .attach(DbConn::fairing())
+fn launch() -> _ {
+    mozaic4_backend::rocket()
 }
diff --git a/backend/tests/common.rs b/backend/tests/common.rs
index e69de29..8ab68a1 100644
--- a/backend/tests/common.rs
+++ b/backend/tests/common.rs
@@ -0,0 +1,75 @@
+extern crate mozaic4_backend;
+
+use diesel;
+use diesel::prelude::*;
+use mozaic4_backend::DbConn;
+use rocket::http::{ContentType, Header, Status};
+use rocket::local::asynchronous::Client;
+
+// We use a lock to synchronize between tests so DB operations don't collide.
+// For now. In the future, we'll have a nice way to run each test in a DB
+// transaction so we can regain concurrency.
+static DB_LOCK: parking_lot::Mutex<()> = parking_lot::const_mutex(());
+
+async fn reset_db(db: &DbConn) {
+    db.run(|conn| {
+        diesel::sql_query("TRUNCATE TABLE users, sessions")
+            .execute(conn)
+            .expect("drop all tables");
+    })
+    .await
+}
+
+macro_rules! run_test {
+    (|$client:ident, $conn:ident| $block:expr) => {{
+        let _lock = DB_LOCK.lock();
+
+        rocket::async_test(async move {
+            let $client = Client::tracked(mozaic4_backend::rocket())
+                .await
+                .expect("Rocket client");
+            let db = mozaic4_backend::DbConn::get_one($client.rocket()).await;
+            let $conn = db.expect("failed to get database connection for testing");
+            reset_db(&$conn).await;
+
+            $block
+        })
+    }};
+}
+
+#[test]
+fn test_registration() {
+    run_test!(|client, _conn| {
+        let response = client
+            .post("/register")
+            .header(ContentType::JSON)
+            .body(r#"{"username": "piepkonijn", "password": "geheim123"}"#)
+            .dispatch()
+            .await;
+
+        assert_eq!(response.status(), Status::Ok);
+        assert_eq!(response.content_type(), Some(ContentType::JSON));
+
+        let response = client
+            .post("/login")
+            .header(ContentType::JSON)
+            .body(r#"{"username": "piepkonijn", "password": "geheim123"}"#)
+            .dispatch()
+            .await;
+
+        assert_eq!(response.status(), Status::Ok);
+        let token = response.into_string().await.unwrap();
+
+        let response = client
+            .get("/users/me")
+            .header(Header::new("Authorization", token))
+            .dispatch()
+            .await;
+
+        assert_eq!(response.status(), Status::Ok);
+        assert_eq!(response.content_type(), Some(ContentType::JSON));
+        let resp = response.into_string().await.unwrap();
+        let json: serde_json::Value = serde_json::from_str(&resp).unwrap();
+        assert_eq!(json["username"], "piepkonijn");
+    });
+}