diff --git a/tiled/_tests/test_utils.py b/tiled/_tests/test_utils.py
new file mode 100644
index 000000000..f31fe86b1
--- /dev/null
+++ b/tiled/_tests/test_utils.py
@@ -0,0 +1,61 @@
+from ..utils import ensure_specified_sql_driver
+
+
+def test_ensure_specified_sql_driver():
+    # Postgres
+    # Default driver is added if missing.
+    assert (
+        ensure_specified_sql_driver(
+            "postgresql://user:password@localhost:5432/database"
+        )
+        == "postgresql+asyncpg://user:password@localhost:5432/database"
+    )
+    # Default driver passes through if specified.
+    assert (
+        ensure_specified_sql_driver(
+            "postgresql+asyncpg://user:password@localhost:5432/database"
+        )
+        == "postgresql+asyncpg://user:password@localhost:5432/database"
+    )
+    # Do not override user-provided.
+    assert (
+        ensure_specified_sql_driver(
+            "postgresql+custom://user:password@localhost:5432/database"
+        )
+        == "postgresql+custom://user:password@localhost:5432/database"
+    )
+
+    # SQLite
+    # Default driver is added if missing.
+    assert (
+        ensure_specified_sql_driver("sqlite:////test.db")
+        == "sqlite+aiosqlite:////test.db"
+    )
+    # Default driver passes through if specified.
+    assert (
+        ensure_specified_sql_driver("sqlite+aiosqlite:////test.db")
+        == "sqlite+aiosqlite:////test.db"
+    )
+    # Do not override user-provided.
+    assert (
+        ensure_specified_sql_driver("sqlite+custom:////test.db")
+        == "sqlite+custom:////test.db"
+    )
+    # Handle SQLite :memory: URIs
+    assert (
+        ensure_specified_sql_driver("sqlite+aiosqlite://:memory:")
+        == "sqlite+aiosqlite://:memory:"
+    )
+    assert (
+        ensure_specified_sql_driver("sqlite://:memory:")
+        == "sqlite+aiosqlite://:memory:"
+    )
+    # Handle SQLite relative URIs
+    assert (
+        ensure_specified_sql_driver("sqlite+aiosqlite:///test.db")
+        == "sqlite+aiosqlite:///test.db"
+    )
+    assert (
+        ensure_specified_sql_driver("sqlite:///test.db")
+        == "sqlite+aiosqlite:///test.db"
+    )
diff --git a/tiled/utils.py b/tiled/utils.py
index c9744f320..eefdc9529 100644
--- a/tiled/utils.py
+++ b/tiled/utils.py
@@ -739,11 +739,9 @@ def ensure_specified_sql_driver(uri: str) -> str:
     'postgresql+asyncpg://...' -> 'postgresql+asynpg://...'
     'postgresql+my_custom_driver://...' -> 'postgresql+my_custom_driver://...'
     """
-    parsed_uri = urlparse(uri)
-    scheme = parsed_uri.scheme
+    scheme, rest = uri.split(":", 1)
     new_scheme = SCHEME_TO_SCHEME_PLUS_DRIVER.get(scheme, scheme)
-    updated_uri = urlunparse(parsed_uri._replace(scheme=new_scheme))
-    return updated_uri
+    return ":".join([new_scheme, rest])
 
 
 class catch_warning_msg(warnings.catch_warnings):