diff --git a/test/server/startup_test.gleam b/test/server/startup_test.gleam
index f38c1d9..9c57a3e 100644
--- a/test/server/startup_test.gleam
+++ b/test/server/startup_test.gleam
@@ -256,3 +256,25 @@ pub fn get_startup_members_test() -> Nil {
 
   Nil
 }
+
+pub fn ensure_exists_test() -> Nil {
+  use context <- server_test.with_context()
+
+  // We are passing a random value.
+  let want = uuid.v7()
+
+  // The query should early return to avoid interacting with a Startup
+  // that does not exist.
+  let assert Error(startup.NotFound(got)) = {
+    use <- startup.ensure_exists(context.database, want)
+
+    Ok(Nil)
+    // ^^^ Depite the callback function ending with an Ok(_), this function
+    // should always return an Error(_) since the Startup does not exist.
+  }
+
+  // The error should include the given ID in his payload
+  assert got == want as "return missing startup id"
+
+  Nil
+}