1 files changed, 79 insertions, 0 deletions
diff --git a/lib/python2.7/test/test_bufio.py b/lib/python2.7/test/test_bufio.py
new file mode 100644
index 0000000..108b1e1
--- /dev/null
+++ b/lib/python2.7/test/test_bufio.py
@@ -0,0 +1,79 @@
+import unittest
+from test import test_support as support
+
+import io # C implementation.
+import _pyio as pyio # Python implementation.
+
+# Simple test to ensure that optimizations in the IO library deliver the
+# expected results.  For best testing, run this under a debug-build Python too
+# (to exercise asserts in the C code).
+
+lengths = list(range(1, 257)) + [512, 1000, 1024, 2048, 4096, 8192, 10000,
+                                 16384, 32768, 65536, 1000000]
+
+class BufferSizeTest(unittest.TestCase):
+    def try_one(self, s):
+        # Write s + "\n" + s to file, then open it and ensure that successive
+        # .readline()s deliver what we wrote.
+
+        # Ensure we can open TESTFN for writing.
+        support.unlink(support.TESTFN)
+
+        # Since C doesn't guarantee we can write/read arbitrary bytes in text
+        # files, use binary mode.
+        f = self.open(support.TESTFN, "wb")
+        try:
+            # write once with \n and once without
+            f.write(s)
+            f.write(b"\n")
+            f.write(s)
+            f.close()
+            f = open(support.TESTFN, "rb")
+            line = f.readline()
+            self.assertEqual(line, s + b"\n")
+            line = f.readline()
+            self.assertEqual(line, s)
+            line = f.readline()
+            self.assertTrue(not line) # Must be at EOF
+            f.close()
+        finally:
+            support.unlink(support.TESTFN)
+
+    def drive_one(self, pattern):
+        for length in lengths:
+            # Repeat string 'pattern' as often as needed to reach total length
+            # 'length'.  Then call try_one with that string, a string one larger
+            # than that, and a string one smaller than that.  Try this with all
+            # small sizes and various powers of 2, so we exercise all likely
+            # stdio buffer sizes, and "off by one" errors on both sides.
+            q, r = divmod(length, len(pattern))
+            teststring = pattern * q + pattern[:r]
+            self.assertEqual(len(teststring), length)
+            self.try_one(teststring)
+            self.try_one(teststring + b"x")
+            self.try_one(teststring[:-1])
+
+    def test_primepat(self):
+        # A pattern with prime length, to avoid simple relationships with
+        # stdio buffer sizes.
+        self.drive_one(b"1234567890\00\01\02\03\04\05\06")
+
+    def test_nullpat(self):
+        self.drive_one(bytes(1000))
+
+
+class CBufferSizeTest(BufferSizeTest):
+    open = io.open
+
+class PyBufferSizeTest(BufferSizeTest):
+    open = staticmethod(pyio.open)
+
+class BuiltinBufferSizeTest(BufferSizeTest):
+    open = open
+
+
+def test_main():
+    support.run_unittest(CBufferSizeTest, PyBufferSizeTest, BuiltinBufferSizeTest)
+
+if __name__ == "__main__":
+    test_main()