Add a challenge for buffer type

Author: laike9m

challenges/advanced-buffer/question.py

@@ -0,0 +1,35 @@
+"""
+TODO:
+
+Annotate the function `read_buffer`, which accepts anything that is a buffer.
+
+See https://docs.python.org/3.12/reference/datamodel.html#object.__buffer__
+"""
+
+
+def read_buffer(b):
+    ...
+
+
+## End of your code ##
+
+from array import array
+
+
+class MyBuffer:
+    def __init__(self, data: bytes):
+        self.data = bytearray(data)
+        self.view = None
+
+    def __buffer__(self, flags: int) -> memoryview:
+        self.view = memoryview(self.data)
+        return self.view
+
+
+read_buffer(b"foo")
+read_buffer(memoryview(b"foo"))
+read_buffer(array("l", [1, 2, 3, 4, 5]))
+read_buffer(MyBuffer(b"foo"))
+read_buffer("foo")  # expect-type-error
+read_buffer(1)  # expect-type-error
+read_buffer(["foo"])  # expect-type-error

challenges/advanced-buffer/solution.py

@@ -0,0 +1,37 @@
+"""
+TODO:
+
+Annotate the function `read_buffer`, which accepts anything that is a buffer.
+
+See https://docs.python.org/3.12/reference/datamodel.html#object.__buffer__
+"""
+
+from collections.abc import Buffer
+
+
+def read_buffer(b: Buffer):
+    ...
+
+
+## End of your code ##
+
+from array import array
+
+
+class MyBuffer:
+    def __init__(self, data: bytes):
+        self.data = bytearray(data)
+        self.view = None
+
+    def __buffer__(self, flags: int) -> memoryview:
+        self.view = memoryview(self.data)
+        return self.view
+
+
+read_buffer(b"foo")
+read_buffer(memoryview(b"foo"))
+read_buffer(array("l", [1, 2, 3, 4, 5]))
+read_buffer(MyBuffer(b"foo"))
+read_buffer("foo")  # expect-type-error
+read_buffer(1)  # expect-type-error
+read_buffer(["foo"])  # expect-type-error