diff --git a/xarray/tests/test_datatree.py b/xarray/tests/test_datatree.py
index 715d80e084a..c87a1e1329e 100644
--- a/xarray/tests/test_datatree.py
+++ b/xarray/tests/test_datatree.py
@@ -1,7 +1,7 @@
 import re
 import sys
 import typing
-from collections.abc import Mapping
+from collections.abc import Callable, Mapping
 from copy import copy, deepcopy
 from textwrap import dedent
 
@@ -1589,27 +1589,53 @@ def test_assign(self) -> None:
 
 
 class TestPipe:
-    def test_noop(self, create_test_datatree) -> None:
+    def test_noop(self, create_test_datatree: Callable[[], DataTree]) -> None:
         dt = create_test_datatree()
 
         actual = dt.pipe(lambda tree: tree)
         assert actual.identical(dt)
 
-    def test_params(self, create_test_datatree) -> None:
+    def test_args(self, create_test_datatree: Callable[[], DataTree]) -> None:
         dt = create_test_datatree()
 
-        def f(tree, **attrs):
-            return tree.assign(arr_with_attrs=xr.Variable("dim0", [], attrs=attrs))
+        def f(tree: DataTree, x: int, y: int) -> DataTree:
+            return tree.assign(
+                arr_with_attrs=xr.Variable("dim0", [], attrs=dict(x=x, y=y))
+            )
+
+        actual = dt.pipe(f, 1, 2)
+        assert actual["arr_with_attrs"].attrs == dict(x=1, y=2)
+
+    def test_kwargs(self, create_test_datatree: Callable[[], DataTree]) -> None:
+        dt = create_test_datatree()
+
+        def f(tree: DataTree, *, x: int, y: int, z: int) -> DataTree:
+            return tree.assign(
+                arr_with_attrs=xr.Variable("dim0", [], attrs=dict(x=x, y=y, z=z))
+            )
 
         attrs = {"x": 1, "y": 2, "z": 3}
 
         actual = dt.pipe(f, **attrs)
         assert actual["arr_with_attrs"].attrs == attrs
 
-    def test_named_self(self, create_test_datatree) -> None:
+    def test_args_kwargs(self, create_test_datatree: Callable[[], DataTree]) -> None:
+        dt = create_test_datatree()
+
+        def f(tree: DataTree, x: int, *, y: int, z: int) -> DataTree:
+            return tree.assign(
+                arr_with_attrs=xr.Variable("dim0", [], attrs=dict(x=x, y=y, z=z))
+            )
+
+        attrs = {"x": 1, "y": 2, "z": 3}
+
+        actual = dt.pipe(f, attrs["x"], y=attrs["y"], z=attrs["z"])
+        assert actual["arr_with_attrs"].attrs == attrs
+
+    def test_named_self(self, create_test_datatree: Callable[[], DataTree]) -> None:
         dt = create_test_datatree()
 
-        def f(x, tree, y):
+        def f(x: int, tree: DataTree, y: int):
             tree.attrs.update({"x": x, "y": y})
             return tree