Fix SimpleReader traversal adapters

.coveragerc

@@ -4,7 +4,6 @@ omit =
 	*/.tox/*
 	*/_itertools.py
 	*/_legacy.py
-	*/simple.py
 	*/_path.py
 disable_warnings =
 	couldnt-parse

importlib_resources/simple.py

@@ -55,14 +55,18 @@ class ResourceContainer(Traversable):
     def __init__(self, reader: SimpleReader):
         self.reader = reader
 
+    @property
+    def name(self):
+        return self.reader.name
+
     def is_dir(self):
         return True
 
     def is_file(self):
         return False
 
     def iterdir(self):
-        files = (ResourceHandle(self, name) for name in self.reader.resources)
+        files = (ResourceHandle(self, name) for name in self.reader.resources())
         dirs = map(ResourceContainer, self.reader.children())
         return itertools.chain(files, dirs)
 
@@ -77,7 +81,14 @@ 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 iterdir(self):
+        return iter(())
 
     def is_file(self):
         return True
@@ -91,7 +102,9 @@ def open(self, mode='r', *args, **kwargs):
             stream = io.TextIOWrapper(stream, *args, **kwargs)
         return stream
 
-    def joinpath(self, name):
+    def joinpath(self, *descendants):
+        if not descendants:
+            return self
         raise RuntimeError("Cannot traverse into a resource")
 
 

importlib_resources/tests/test_simple.py

@@ -0,0 +1,79 @@
+import io
+import unittest
+
+from importlib_resources.simple import TraversableReader
+
+
+class MemoryReader(TraversableReader):
+    def __init__(self, package, resources=None, children=None):
+        self._package = package
+        self._resources = resources or {}
+        self._children = children or []
+
+    @property
+    def package(self):
+        return self._package
+
+    def children(self):
+        return self._children
+
+    def resources(self):
+        return list(self._resources)
+
+    def open_binary(self, resource):
+        return io.BytesIO(self._resources[resource])
+
+
+class SimpleReaderTest(unittest.TestCase):
+    def setUp(self):
+        child = MemoryReader('sample.package.child', {'nested.txt': b'nested'})
+        self.reader = MemoryReader(
+            'sample.package',
+            {'data.txt': 'hello, café'.encode()},
+            [child],
+        )
+
+    def test_files(self):
+        root = self.reader.files()
+        assert root.name == 'package'
+        assert root.is_dir()
+        assert not root.is_file()
+        assert root.joinpath() is root
+        with self.assertRaises(IsADirectoryError):
+            root.open()
+
+    def test_iterdir(self):
+        entries = {item.name: item for item in self.reader.files().iterdir()}
+        assert set(entries) == {'data.txt', 'child'}
+        assert entries['data.txt'].is_file()
+        assert not entries['data.txt'].is_dir()
+        assert entries['child'].is_dir()
+        assert not entries['child'].is_file()
+        assert set(self.reader.contents()) == {'data.txt', 'child'}
+
+    def test_read_resource(self):
+        resource = self.reader.files().joinpath('data.txt')
+        assert resource.read_bytes() == 'hello, café'.encode()
+        assert resource.read_text(encoding='utf-8') == 'hello, café'
+        with self.reader.open_resource('data.txt') as stream:
+            assert stream.read() == 'hello, café'.encode()
+        assert self.reader.is_resource('data.txt')
+        assert not self.reader.is_resource('child')
+
+    def test_nested_resource(self):
+        root = self.reader.files()
+        assert root.joinpath('child', 'nested.txt').read_bytes() == b'nested'
+        assert root.joinpath('child/nested.txt').read_bytes() == b'nested'
+        assert (root / 'child' / 'nested.txt').read_bytes() == b'nested'
+
+    def test_resource_has_no_children(self):
+        resource = self.reader.files().joinpath('data.txt')
+        assert list(resource.iterdir()) == []
+        assert resource.joinpath() is resource
+        with self.assertRaisesRegex(RuntimeError, 'Cannot traverse into a resource'):
+            resource.joinpath('child')
+
+    def test_empty_reader(self):
+        root = MemoryReader('empty').files()
+        assert root.name == 'empty'
+        assert list(root.iterdir()) == []

newsfragments/+simple-reader-adapter.bugfix.rst

@@ -0,0 +1 @@
+Fix the SimpleReader adapters to support resource enumeration, traversal, and reading through TraversableReader.