From e88a213f5b73ce903700d0ad863b3cbbcb5adeee Mon Sep 17 00:00:00 2001
From: Kyle Barron <kyle@developmentseed.org>
Date: Mon, 20 Oct 2025 19:52:38 -0400
Subject: [PATCH 1/2] fix: Ensure that the default value of `Map.basemap` is
 `MaplibreBasemap` if no value of `basemap` was passed.

---
 lonboard/_map.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lonboard/_map.py b/lonboard/_map.py
index b99e8520..e86ea75b 100644
--- a/lonboard/_map.py
+++ b/lonboard/_map.py
@@ -221,6 +221,9 @@ def on_click(self, callback: Callable, *, remove: bool = False) -> None:
 
     basemap: t.Instance[MaplibreBasemap | None] = t.Instance(
         MaplibreBasemap,
+        # If both `args` and `kw` are None, then the default value is None.
+        # Set empty kw so that the default is MaplibreBasemap() with default params
+        kw={},
         allow_none=True,
     ).tag(
         sync=True,

From f27aeac8f7af3ac86136a53892de189a557fac47 Mon Sep 17 00:00:00 2001
From: Kyle Barron <kyle@developmentseed.org>
Date: Mon, 20 Oct 2025 19:53:24 -0400
Subject: [PATCH 2/2] add test

---
 tests/test_map.py | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/tests/test_map.py b/tests/test_map.py
index 4dee1d30..4e6970b0 100644
--- a/tests/test_map.py
+++ b/tests/test_map.py
@@ -2,6 +2,7 @@
 from traitlets import TraitError
 
 from lonboard import Map, ScatterplotLayer, SolidPolygonLayer
+from lonboard.basemap import MaplibreBasemap
 
 
 def test_map_fails_with_unexpected_argument():
@@ -38,3 +39,13 @@ def allow_single_layer():
 def test_map_basemap_non_url():
     with pytest.raises(TraitError, match=r"expected to be a HTTP\(s\) URL"):
         _m = Map([], basemap_style="hello world")
+
+
+def test_map_default_basemap():
+    m = Map([])
+    assert isinstance(m.basemap, MaplibreBasemap), (
+        "Default basemap should be MaplibreBasemap"
+    )
+
+    assert m.basemap.mode == MaplibreBasemap().mode, "Should match default parameters"
+    assert m.basemap.style == MaplibreBasemap().style, "Should match default parameters"