test: Add tests for importlib.resources.simple module

Add tests for ResourceContainer and ResourceHandle classes to verify:
- ResourceContainer instantiation with name property
- ResourceContainer.iterdir() calling resources() method
- ResourceHandle.joinpath() accepting *descendants parameter
- ResourceHandle.iterdir() returning empty iterator
- ResourceHandle name as property instead of instance variable

Also fix ResourceHandle.name to be a property to satisfy Traversable
abstract base class requirements.

Author: stefanzetzsche

Lib/importlib/resources/simple.py

@@ -81,7 +81,11 @@ class ResourceHandle(Traversable):
 
     def __init__(self, parent: ResourceContainer, name: str):
         self.parent = parent
-        self.name = name  # type: ignore[misc]
+        self._name = name
+
+    @property
+    def name(self):
+        return self._name
 
     def is_file(self):
         return True

Lib/test/test_importlib/resources/test_reader.py

@@ -1,9 +1,11 @@
+import io
 import os.path
 import pathlib
 import unittest
 
 from importlib import import_module
 from importlib.readers import MultiplexedPath, NamespaceReader
+from importlib.resources.simple import ResourceContainer, ResourceHandle, SimpleReader
 
 from . import util
 
@@ -133,5 +135,67 @@ def test_files(self):
         self.assertEqual(repr(reader.files()), f"MultiplexedPath('{root}')")
 
 
+class SimpleReaderTest(unittest.TestCase):
+    def test_resource_container_instantiation(self):
+        class R(SimpleReader):
+            @property
+            def package(self):
+                return 'x'
+
+            def children(self):
+                return []
+
+            def resources(self):
+                return []
+
+            def open_binary(self, r):
+                return io.BytesIO(b'')
+
+        container = ResourceContainer(R())
+        self.assertEqual(container.name, 'x')
+        self.assertTrue(container.is_dir())
+
+    def test_resource_container_iterdir(self):
+        class R(SimpleReader):
+            @property
+            def package(self):
+                return 'test'
+
+            def children(self):
+                return []
+
+            def resources(self):
+                return ['file.txt']
+
+            def open_binary(self, r):
+                return io.BytesIO(b'data')
+
+        container = ResourceContainer(R())
+        items = list(container.iterdir())
+        self.assertEqual(len(items), 1)
+        self.assertIsInstance(items[0], ResourceHandle)
+
+    def test_resource_handle_joinpath(self):
+        class R(SimpleReader):
+            @property
+            def package(self):
+                return 'test'
+
+            def children(self):
+                return []
+
+            def resources(self):
+                return []
+
+            def open_binary(self, r):
+                return io.BytesIO(b'')
+
+        container = ResourceContainer(R())
+        handle = ResourceHandle(container, 'file.txt')
+        self.assertIs(handle.joinpath(), handle)
+        with self.assertRaises(RuntimeError):
+            handle.joinpath('subpath')
+
+
 if __name__ == '__main__':
     unittest.main()