diff --git a/tests/test_preprocessing.py b/tests/test_preprocessing.py
index 1354777ed5..36c1726333 100644
--- a/tests/test_preprocessing.py
+++ b/tests/test_preprocessing.py
@@ -144,7 +144,7 @@ def test_normalize_per_cell():
 
 
 @pytest.mark.parametrize("array_type", ARRAY_TYPES)
-@pytest.mark.parametrize("copy", [True, False], ids=["copy", "inplace"])
+@pytest.mark.parametrize("which", ["copy", "inplace", "array"])
 @pytest.mark.parametrize(
     ("axis", "fraction", "n", "replace", "expected"),
     [
@@ -160,7 +160,7 @@ def test_normalize_per_cell():
 def test_sample(
     *,
     array_type: Callable[[np.ndarray], np.ndarray | CSMatrix],
-    copy: bool,
+    which: Literal["copy", "inplace", "array"],
     axis: Literal[0, 1],
     fraction: float | None,
     n: int | None,
@@ -174,14 +174,30 @@ def test_sample(
     warnings.filterwarnings(
         "ignore" if replace else "error", r".*names are not unique", UserWarning
     )
-    rv = sc.pp.sample(adata, fraction, n=n, replace=replace, axis=axis, copy=copy)
+    rv = sc.pp.sample(
+        adata.X if which == "array" else adata,
+        fraction,
+        n=n,
+        replace=replace,
+        axis=axis,
+        # `copy` only effects AnnData inputs
+        copy=dict(copy=True, inplace=False, array=False)[which],
+    )
 
-    if copy:
-        assert adata.shape == (200, 10)
-        subset = rv
-    else:
-        assert rv is None
-        subset = adata
+    match which:
+        case "copy":
+            subset = rv
+            assert rv is not adata
+            assert adata.shape == (200, 10)
+        case "inplace":
+            subset = adata
+            assert rv is None
+        case "array":
+            subset, indices = rv
+            assert len(indices) == expected
+            assert adata.shape == (200, 10)
+        case _:
+            pytest.fail(f"Unknown `{which=}`")
 
     assert subset.shape == ((expected, 10) if axis == 0 else (200, expected))