Merge pull request python#9 from brettcannon/implement-read

Implement read()

Author: brettcannon

importlib_resources/__init__.py

@@ -54,3 +54,21 @@ def open(package: Package, file_name: Path) -> BinaryIO:
     loader = typing.cast(importlib.abc.ResourceLoader, package.__spec__.loader)
     data = loader.get_data(full_path)
     return io.BytesIO(data)
+
+
+def read(package: Package, file_name: Path, encoding: str = 'utf-8',
+         errors: str = 'strict') -> str:
+    """Return the decoded string of the resource.
+
+    The decoding-related arguments have the same semantics as those of
+    bytes.decode().
+    """
+    file_name = _normalize_path(file_name)
+    package = _get_package(package)
+    # Note this is **not** builtins.open()!
+    with open(package, file_name) as binary_file:
+        # Decoding from io.TextIOWrapper() instead of str.decode() in hopes that
+        # the former will be smarter about memory usage.
+        text_file = io.TextIOWrapper(binary_file, encoding=encoding,
+                                     errors=errors)
+        return text_file.read()

importlib_resources/tests/data/utf-16.file

@@ -1 +1 @@
-Hello, world!
+Hello, UTF-8 world!

importlib_resources/tests/data/utf-8.file

@@ -35,7 +35,7 @@ def test_pathlib_path(self):
 
     def test_absolute_path(self):
         # An absolute path is a ValueError.
-        path = pathlib.Path(__spec__.origin)
+        path = pathlib.Path(__file__)
         full_path = path.parent/'utf-8.file'
         with self.assertRaises(ValueError):
             with resources.open(data, str(full_path)) as file:
@@ -65,13 +65,13 @@ class OpenTests(unittest.TestCase):
     def test_opened_for_reading(self):
         # The file-like object is ready for reading.
         with resources.open(data, 'utf-8.file') as file:
-            self.assertEqual(b"Hello, world!\n", file.read())
+            self.assertEqual(b"Hello, UTF-8 world!\n", file.read())
 
     def test_wrap_for_text(self):
         # The file-like object can be wrapped for text reading.
         with resources.open(data, 'utf-8.file') as file:
             text_file = io.TextIOWrapper(file, encoding='utf-8')
-            self.assertEqual('Hello, world!\n', text_file.read())
+            self.assertEqual('Hello, UTF-8 world!\n', text_file.read())
 
 
 if __name__ == '__main__':

importlib_resources/tests/test_open.py

@@ -0,0 +1,68 @@
+import io
+import os.path
+import pathlib
+import sys
+import unittest
+
+import importlib_resources as resources
+from importlib_resources.tests import data
+
+
+class CommonTests(unittest.TestCase):
+
+    def test_package_name(self):
+        # Passing in the package name should succeed.
+        resources.read(data.__name__, 'utf-8.file')
+
+    def test_package_object(self):
+        # Passing in the package itself should succeed.
+        resources.read(data, 'utf-8.file')
+
+    def test_string_path(self):
+        path = 'utf-8.file'
+        # Passing in a string for the path should succeed.
+        resources.read(data, path)
+
+    @unittest.skipIf(sys.version_info < (3, 6), 'requires os.PathLike support')
+    def test_pathlib_path(self):
+        # Passing in a pathlib.PurePath object for the path should succeed.
+        path = pathlib.PurePath('utf-8.file')
+        resources.read(data, path)
+
+    def test_absolute_path(self):
+        # An absolute path is a ValueError.
+        path = pathlib.Path(__file__)
+        full_path = path.parent/'utf-8.file'
+        with self.assertRaises(ValueError):
+            resources.read(data, str(full_path))
+
+    def test_relative_path(self):
+        # A reative path is a ValueError.
+        with self.assertRaises(ValueError):
+            resources.read(data, '../data/utf-8.file')
+
+    def test_importing_module_as_side_effect(self):
+        # The anchor package can already be imported.
+        del sys.modules[data.__name__]
+        resources.read(data.__name__, 'utf-8.file')
+
+    def test_non_package(self):
+        # The anchor package cannot be a module.
+        with self.assertRaises(TypeError):
+            resources.read(__spec__.name, 'utf-8.file')
+
+
+class ReadTests(unittest.TestCase):
+
+    def test_default_encoding(self):
+        result = resources.read(data, 'utf-8.file')
+        self.assertEqual("Hello, UTF-8 world!\n", result)
+
+    def test_encoding(self):
+        result = resources.read(data, 'utf-16.file', encoding='utf-16')
+        self.assertEqual("Hello, UTF-16 world!\n", result)
+
+    def test_errors(self):
+        # Raises UnicodeError without the 'errors' argument.
+        result = resources.read(data, 'utf-16.file', encoding='utf-8',
+                                errors='ignore')