scripts: testedtlib: add more child-binding tests

The child_binding object should default to having a path and
compatible that matches the parent's. Mark it as xfail because the
compatible part is failing.

Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>

scripts/dts/test-bindings/child-binding-with-compat.yaml

@@ -0,0 +1,20 @@
+# SPDX-License-Identifier: BSD-3-Clause
+
+description: child-binding with separate compatible than the parent
+
+compatible: "child-binding-with-compat"
+
+child-binding:
+    compatible: child-compat
+    description: child node
+    properties:
+        child-prop:
+            type: int
+            required: true
+
+    child-binding:
+        description: grandchild node
+        properties:
+            grandchild-prop:
+                type: int
+                required: true

scripts/dts/testedtlib.py

@@ -137,6 +137,7 @@ def test_bus():
     assert str(edt.get_node("/buses/foo-bus/node/nested").binding_path) == \
         hpath("test-bindings/device-on-foo-bus.yaml")
 
+@pytest.mark.xfail
 def test_child_binding():
     '''Test 'child-binding:' in bindings'''
     edt = edtlib.EDT("test.dts", ["test-bindings"])
@@ -156,6 +157,22 @@ def test_child_binding():
     assert str(grandchild.description) == "grandchild node"
     assert str(grandchild.props) == "OrderedDict([('grandchild-prop', <Property, name: grandchild-prop, type: int, value: 2>)])"
 
+    binding_file = Path("test-bindings/child-binding.yaml").resolve()
+    top = edtlib.Binding(binding_file, {})
+    child = top.child_binding
+    assert Path(top.path) == binding_file
+    assert Path(child.path) == binding_file
+    assert top.compatible == 'child-binding'
+    assert child.compatible == 'child-binding'
+
+    binding_file = Path("test-bindings/child-binding-with-compat.yaml").resolve()
+    top = edtlib.Binding(binding_file, {})
+    child = top.child_binding
+    assert Path(top.path) == binding_file
+    assert Path(child.path) == binding_file
+    assert top.compatible == 'child-binding-with-compat'
+    assert child.compatible == 'child-compat'
+
 def test_props():
     '''Test Node.props (derived from DT and 'properties:' in the binding)'''
     edt = edtlib.EDT("test.dts", ["test-bindings"])