Fix issue where single object returns object itself (#666)

Fixes an issue where a singular object was not wrapped in `SubplotGrid` if index as a singular.

Author: cvanelteren

ultraplot/gridspec.py

@@ -1992,7 +1992,7 @@ def __getitem__(self, key):
         # De-duplicate while preserving order so method dispatch does not repeat.
         objs = list(dict.fromkeys(objs))
         if len(objs) == 1:
-            return objs[0]
+            return SubplotGrid(objs[0])
         return SubplotGrid(objs)
 
     def __setitem__(self, key, value):

ultraplot/tests/test_gridspec.py

@@ -4,6 +4,13 @@
 from ultraplot.gridspec import SubplotGrid
 
 
+def _singleton_axis(obj):
+    if isinstance(obj, SubplotGrid):
+        assert len(obj) == 1
+        return obj[0]
+    return obj
+
+
 def test_grid_has_dynamic_methods():
     """
     Check that we can apply the methods to a SubplotGrid object.
@@ -135,8 +142,9 @@ def test_gridspec_spanning_slice_deduplicates_axes():
 
     # The first two slots in the top row refer to the same spanning subplot.
     ax = axs[0, :2]
-    assert isinstance(ax, uplt.axes.Axes)
-    assert ax is axs[0, 0]
+    assert isinstance(ax, uplt.SubplotGrid)
+    assert len(ax) == 1
+    assert _singleton_axis(ax) is _singleton_axis(axs[0, 0])
 
     data = np.array([[0.1, 0.2], [0.4, 0.5], [0.7, 0.8]])
     ax.scatter(data[:, 0], data[:, 1], c="grey", label="data", legend=True)
@@ -145,3 +153,15 @@ def test_gridspec_spanning_slice_deduplicates_axes():
     legend = ax.get_legend()
     assert legend is not None
     assert [t.get_text() for t in legend.texts] == ["data"]
+
+
+def test_return_type_after_indexing():
+    """
+    Inexing should always return a SubplotGrid even if we have 1 element
+    """
+    fig, axs = uplt.subplots(ncols=2, nrows=2)
+    assert isinstance(axs[1, 0:], uplt.SubplotGrid)
+    assert len(axs[1, 0:]) == 2
+
+    assert isinstance(axs[1, 1:], uplt.SubplotGrid)
+    assert len(axs[1, 1:]) == 1

ultraplot/tests/test_legend.py

@@ -1355,29 +1355,33 @@ def test_legend_span_inference_with_multi_panels(
 def test_legend_best_axis_selection_right_left():
     fig, axs = uplt.subplots(nrows=1, ncols=3)
     axs.plot([0, 1], [0, 1], label="line")
-    ref = [axs[0, 0], axs[0, 2]]
+    left = _anchor_axis(axs[0, 0])
+    right = _anchor_axis(axs[0, 2])
+    ref = [left, right]
 
     fig.legend(ref=ref, loc="r", rows=1)
-    assert len(axs[0, 2]._panel_dict["right"]) == 1
-    assert len(axs[0, 0]._panel_dict["right"]) == 0
+    assert len(right._panel_dict["right"]) == 1
+    assert len(left._panel_dict["right"]) == 0
 
     fig.legend(ref=ref, loc="l", rows=1)
-    assert len(axs[0, 0]._panel_dict["left"]) == 1
-    assert len(axs[0, 2]._panel_dict["left"]) == 0
+    assert len(left._panel_dict["left"]) == 1
+    assert len(right._panel_dict["left"]) == 0
 
 
 def test_legend_best_axis_selection_top_bottom():
     fig, axs = uplt.subplots(nrows=2, ncols=1)
     axs.plot([0, 1], [0, 1], label="line")
-    ref = [axs[0, 0], axs[1, 0]]
+    top = _anchor_axis(axs[0, 0])
+    bottom = _anchor_axis(axs[1, 0])
+    ref = [top, bottom]
 
     fig.legend(ref=ref, loc="t", cols=1)
-    assert len(axs[0, 0]._panel_dict["top"]) == 1
-    assert len(axs[1, 0]._panel_dict["top"]) == 0
+    assert len(top._panel_dict["top"]) == 1
+    assert len(bottom._panel_dict["top"]) == 0
 
     fig.legend(ref=ref, loc="b", cols=1)
-    assert len(axs[1, 0]._panel_dict["bottom"]) == 1
-    assert len(axs[0, 0]._panel_dict["bottom"]) == 0
+    assert len(bottom._panel_dict["bottom"]) == 1
+    assert len(top._panel_dict["bottom"]) == 0
 
 
 def test_legend_span_decode_fallback(monkeypatch):

ultraplot/tests/test_subplots.py

@@ -9,6 +9,13 @@
 import ultraplot as uplt
 
 
+def _singleton_axis(obj):
+    if isinstance(obj, uplt.SubplotGrid):
+        assert len(obj) == 1
+        return obj[0]
+    return obj
+
+
 @pytest.mark.mpl_image_compare
 def test_align_labels():
     """
@@ -354,7 +361,7 @@ def test_subset_share_xlabels_implicit_column():
         for axi, lab in fig._supxlabel_dict.items()
         if lab.get_text() == "Right-column X"
     ]
-    assert label_axes and label_axes[0] is ax[1, 1]
+    assert label_axes and label_axes[0] is _singleton_axis(ax[1, 1])
 
     uplt.close(fig)
 
@@ -406,7 +413,7 @@ def test_subset_share_ylabels_implicit_row():
     label_axes = [
         axi for axi, lab in fig._supylabel_dict.items() if lab.get_text() == "Top-row Y"
     ]
-    assert label_axes and label_axes[0] is ax[0, 0]
+    assert label_axes and label_axes[0] is _singleton_axis(ax[0, 0])
 
     uplt.close(fig)
 
@@ -493,7 +500,7 @@ def test_subset_share_xlabels_implicit_column_top():
         for axi, lab in fig._supxlabel_dict.items()
         if lab.get_text() == "Right-column X (top)"
     ]
-    assert label_axes and label_axes[0] is ax[0, 1]
+    assert label_axes and label_axes[0] is _singleton_axis(ax[0, 1])
 
     uplt.close(fig)
 
@@ -512,7 +519,7 @@ def test_subset_share_ylabels_implicit_row_right():
         for axi, lab in fig._supylabel_dict.items()
         if lab.get_text() == "Top-row Y (right)"
     ]
-    assert label_axes and label_axes[0] is ax[0, 1]
+    assert label_axes and label_axes[0] is _singleton_axis(ax[0, 1])
 
     uplt.close(fig)