Issue #5863: Rewrite BZ2File in pure Python, and allow it to accept
file-like objects using a new `fileobj` constructor argument.  Patch by
Nadeem Vawda.
diff --git a/Lib/test/test_bz2.py b/Lib/test/test_bz2.py
index be35580..cee38e0 100644
--- a/Lib/test/test_bz2.py
+++ b/Lib/test/test_bz2.py
@@ -21,7 +21,30 @@
 
 class BaseTest(unittest.TestCase):
     "Base for other testcases."
-    TEXT = b'root:x:0:0:root:/root:/bin/bash\nbin:x:1:1:bin:/bin:\ndaemon:x:2:2:daemon:/sbin:\nadm:x:3:4:adm:/var/adm:\nlp:x:4:7:lp:/var/spool/lpd:\nsync:x:5:0:sync:/sbin:/bin/sync\nshutdown:x:6:0:shutdown:/sbin:/sbin/shutdown\nhalt:x:7:0:halt:/sbin:/sbin/halt\nmail:x:8:12:mail:/var/spool/mail:\nnews:x:9:13:news:/var/spool/news:\nuucp:x:10:14:uucp:/var/spool/uucp:\noperator:x:11:0:operator:/root:\ngames:x:12:100:games:/usr/games:\ngopher:x:13:30:gopher:/usr/lib/gopher-data:\nftp:x:14:50:FTP User:/var/ftp:/bin/bash\nnobody:x:65534:65534:Nobody:/home:\npostfix:x:100:101:postfix:/var/spool/postfix:\nniemeyer:x:500:500::/home/niemeyer:/bin/bash\npostgres:x:101:102:PostgreSQL Server:/var/lib/pgsql:/bin/bash\nmysql:x:102:103:MySQL server:/var/lib/mysql:/bin/bash\nwww:x:103:104::/var/www:/bin/false\n'
+    TEXT_LINES = [
+        b'root:x:0:0:root:/root:/bin/bash\n',
+        b'bin:x:1:1:bin:/bin:\n',
+        b'daemon:x:2:2:daemon:/sbin:\n',
+        b'adm:x:3:4:adm:/var/adm:\n',
+        b'lp:x:4:7:lp:/var/spool/lpd:\n',
+        b'sync:x:5:0:sync:/sbin:/bin/sync\n',
+        b'shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown\n',
+        b'halt:x:7:0:halt:/sbin:/sbin/halt\n',
+        b'mail:x:8:12:mail:/var/spool/mail:\n',
+        b'news:x:9:13:news:/var/spool/news:\n',
+        b'uucp:x:10:14:uucp:/var/spool/uucp:\n',
+        b'operator:x:11:0:operator:/root:\n',
+        b'games:x:12:100:games:/usr/games:\n',
+        b'gopher:x:13:30:gopher:/usr/lib/gopher-data:\n',
+        b'ftp:x:14:50:FTP User:/var/ftp:/bin/bash\n',
+        b'nobody:x:65534:65534:Nobody:/home:\n',
+        b'postfix:x:100:101:postfix:/var/spool/postfix:\n',
+        b'niemeyer:x:500:500::/home/niemeyer:/bin/bash\n',
+        b'postgres:x:101:102:PostgreSQL Server:/var/lib/pgsql:/bin/bash\n',
+        b'mysql:x:102:103:MySQL server:/var/lib/mysql:/bin/bash\n',
+        b'www:x:103:104::/var/www:/bin/false\n',
+        ]
+    TEXT = b''.join(TEXT_LINES)
     DATA = b'BZh91AY&SY.\xc8N\x18\x00\x01>_\x80\x00\x10@\x02\xff\xf0\x01\x07n\x00?\xe7\xff\xe00\x01\x99\xaa\x00\xc0\x03F\x86\x8c#&\x83F\x9a\x03\x06\xa6\xd0\xa6\x93M\x0fQ\xa7\xa8\x06\x804hh\x12$\x11\xa4i4\xf14S\xd2<Q\xb5\x0fH\xd3\xd4\xdd\xd5\x87\xbb\xf8\x94\r\x8f\xafI\x12\xe1\xc9\xf8/E\x00pu\x89\x12]\xc9\xbbDL\nQ\x0e\t1\x12\xdf\xa0\xc0\x97\xac2O9\x89\x13\x94\x0e\x1c7\x0ed\x95I\x0c\xaaJ\xa4\x18L\x10\x05#\x9c\xaf\xba\xbc/\x97\x8a#C\xc8\xe1\x8cW\xf9\xe2\xd0\xd6M\xa7\x8bXa<e\x84t\xcbL\xb3\xa7\xd9\xcd\xd1\xcb\x84.\xaf\xb3\xab\xab\xad`n}\xa0lh\tE,\x8eZ\x15\x17VH>\x88\xe5\xcd9gd6\x0b\n\xe9\x9b\xd5\x8a\x99\xf7\x08.K\x8ev\xfb\xf7xw\xbb\xdf\xa1\x92\xf1\xdd|/";\xa2\xba\x9f\xd5\xb1#A\xb6\xf6\xb3o\xc9\xc5y\\\xebO\xe7\x85\x9a\xbc\xb6f8\x952\xd5\xd7"%\x89>V,\xf7\xa6z\xe2\x9f\xa3\xdf\x11\x11"\xd6E)I\xa9\x13^\xca\xf3r\xd0\x03U\x922\xf26\xec\xb6\xed\x8b\xc3U\x13\x9d\xc5\x170\xa4\xfa^\x92\xacDF\x8a\x97\xd6\x19\xfe\xdd\xb8\xbd\x1a\x9a\x19\xa3\x80ankR\x8b\xe5\xd83]\xa9\xc6\x08\x82f\xf6\xb9"6l$\xb8j@\xc0\x8a\xb0l1..\xbak\x83ls\x15\xbc\xf4\xc1\x13\xbe\xf8E\xb8\x9d\r\xa8\x9dk\x84\xd3n\xfa\xacQ\x07\xb1%y\xaav\xb4\x08\xe0z\x1b\x16\xf5\x04\xe9\xcc\xb9\x08z\x1en7.G\xfc]\xc9\x14\xe1B@\xbb!8`'
     DATA_CRLF = b'BZh91AY&SY\xaez\xbbN\x00\x01H\xdf\x80\x00\x12@\x02\xff\xf0\x01\x07n\x00?\xe7\xff\xe0@\x01\xbc\xc6`\x86*\x8d=M\xa9\x9a\x86\xd0L@\x0fI\xa6!\xa1\x13\xc8\x88jdi\x8d@\x03@\x1a\x1a\x0c\x0c\x83 \x00\xc4h2\x19\x01\x82D\x84e\t\xe8\x99\x89\x19\x1ah\x00\r\x1a\x11\xaf\x9b\x0fG\xf5(\x1b\x1f?\t\x12\xcf\xb5\xfc\x95E\x00ps\x89\x12^\xa4\xdd\xa2&\x05(\x87\x04\x98\x89u\xe40%\xb6\x19\'\x8c\xc4\x89\xca\x07\x0e\x1b!\x91UIFU%C\x994!DI\xd2\xfa\xf0\xf1N8W\xde\x13A\xf5\x9cr%?\x9f3;I45A\xd1\x8bT\xb1<l\xba\xcb_\xc00xY\x17r\x17\x88\x08\x08@\xa0\ry@\x10\x04$)`\xf2\xce\x89z\xb0s\xec\x9b.iW\x9d\x81\xb5-+t\x9f\x1a\'\x97dB\xf5x\xb5\xbe.[.\xd7\x0e\x81\xe7\x08\x1cN`\x88\x10\xca\x87\xc3!"\x80\x92R\xa1/\xd1\xc0\xe6mf\xac\xbd\x99\xcca\xb3\x8780>\xa4\xc7\x8d\x1a\\"\xad\xa1\xabyBg\x15\xb9l\x88\x88\x91k"\x94\xa4\xd4\x89\xae*\xa6\x0b\x10\x0c\xd6\xd4m\xe86\xec\xb5j\x8a\x86j\';\xca.\x01I\xf2\xaaJ\xe8\x88\x8cU+t3\xfb\x0c\n\xa33\x13r2\r\x16\xe0\xb3(\xbf\x1d\x83r\xe7M\xf0D\x1365\xd8\x88\xd3\xa4\x92\xcb2\x06\x04\\\xc1\xb0\xea//\xbek&\xd8\xe6+t\xe5\xa1\x13\xada\x16\xder5"w]\xa2i\xb7[\x97R \xe2IT\xcd;Z\x04dk4\xad\x8a\t\xd3\x81z\x10\xf1:^`\xab\x1f\xc5\xdc\x91N\x14$+\x9e\xae\xd3\x80'
 
@@ -54,13 +77,15 @@
         if os.path.isfile(self.filename):
             os.unlink(self.filename)
 
-    def createTempFile(self, crlf=0):
+    def getData(self, crlf=False):
+        if crlf:
+            return self.DATA_CRLF
+        else:
+            return self.DATA
+
+    def createTempFile(self, crlf=False):
         with open(self.filename, "wb") as f:
-            if crlf:
-                data = self.DATA_CRLF
-            else:
-                data = self.DATA
-            f.write(data)
+            f.write(self.getData(crlf))
 
     def testRead(self):
         # "Test BZ2File.read()"
@@ -70,7 +95,7 @@
             self.assertEqual(bz2f.read(), self.TEXT)
 
     def testRead0(self):
-        # Test BBZ2File.read(0)"
+        # "Test BBZ2File.read(0)"
         self.createTempFile()
         with BZ2File(self.filename) as bz2f:
             self.assertRaises(TypeError, bz2f.read, None)
@@ -94,6 +119,28 @@
         with BZ2File(self.filename) as bz2f:
             self.assertEqual(bz2f.read(100), self.TEXT[:100])
 
+    def testPeek(self):
+        # "Test BZ2File.peek()"
+        self.createTempFile()
+        with BZ2File(self.filename) as bz2f:
+            pdata = bz2f.peek()
+            self.assertNotEqual(len(pdata), 0)
+            self.assertTrue(self.TEXT.startswith(pdata))
+            self.assertEqual(bz2f.read(), self.TEXT)
+
+    def testReadInto(self):
+        # "Test BZ2File.readinto()"
+        self.createTempFile()
+        with BZ2File(self.filename) as bz2f:
+            n = 128
+            b = bytearray(n)
+            self.assertEqual(bz2f.readinto(b), n)
+            self.assertEqual(b, self.TEXT[:n])
+            n = len(self.TEXT) - n
+            b = bytearray(len(self.TEXT))
+            self.assertEqual(bz2f.readinto(b), n)
+            self.assertEqual(b[:n], self.TEXT[-n:])
+
     def testReadLine(self):
         # "Test BZ2File.readline()"
         self.createTempFile()
@@ -125,7 +172,7 @@
         bz2f = BZ2File(self.filename)
         bz2f.close()
         self.assertRaises(ValueError, bz2f.__next__)
-        # This call will deadlock of the above .__next__ call failed to
+        # This call will deadlock if the above .__next__ call failed to
         # release the lock.
         self.assertRaises(ValueError, bz2f.readlines)
 
@@ -217,6 +264,13 @@
             self.assertEqual(bz2f.tell(), 0)
             self.assertEqual(bz2f.read(), self.TEXT)
 
+    def testFileno(self):
+        # "Test BZ2File.fileno()"
+        self.createTempFile()
+        with open(self.filename) as rawf:
+            with BZ2File(fileobj=rawf) as bz2f:
+                self.assertEqual(bz2f.fileno(), rawf.fileno())
+
     def testOpenDel(self):
         # "Test opening and deleting a file many times"
         self.createTempFile()
@@ -278,17 +332,65 @@
                 t.join()
 
     def testMixedIterationReads(self):
-        # Issue #8397: mixed iteration and reads should be forbidden.
-        with bz2.BZ2File(self.filename, 'wb') as f:
-            # The internal buffer size is hard-wired to 8192 bytes, we must
-            # write out more than that for the test to stop half through
-            # the buffer.
-            f.write(self.TEXT * 100)
-        with bz2.BZ2File(self.filename, 'rb') as f:
-            next(f)
-            self.assertRaises(ValueError, f.read)
-            self.assertRaises(ValueError, f.readline)
-            self.assertRaises(ValueError, f.readlines)
+        # "Test mixed iteration and reads."
+        self.createTempFile()
+        linelen = len(self.TEXT_LINES[0])
+        halflen = linelen // 2
+        with bz2.BZ2File(self.filename) as bz2f:
+            bz2f.read(halflen)
+            self.assertEqual(next(bz2f), self.TEXT_LINES[0][halflen:])
+            self.assertEqual(bz2f.read(), self.TEXT[linelen:])
+        with bz2.BZ2File(self.filename) as bz2f:
+            bz2f.readline()
+            self.assertEqual(next(bz2f), self.TEXT_LINES[1])
+            self.assertEqual(bz2f.readline(), self.TEXT_LINES[2])
+        with bz2.BZ2File(self.filename) as bz2f:
+            bz2f.readlines()
+            with self.assertRaises(StopIteration):
+                next(bz2f)
+            self.assertEqual(bz2f.readlines(), [])
+
+    def testReadBytesIO(self):
+        # "Test BZ2File.read() with BytesIO source"
+        with BytesIO(self.getData()) as bio:
+            with BZ2File(fileobj=bio) as bz2f:
+                self.assertRaises(TypeError, bz2f.read, None)
+                self.assertEqual(bz2f.read(), self.TEXT)
+            self.assertFalse(bio.closed)
+
+    def testPeekBytesIO(self):
+        # "Test BZ2File.peek() with BytesIO source"
+        with BytesIO(self.getData()) as bio:
+            with BZ2File(fileobj=bio) as bz2f:
+                pdata = bz2f.peek()
+                self.assertNotEqual(len(pdata), 0)
+                self.assertTrue(self.TEXT.startswith(pdata))
+                self.assertEqual(bz2f.read(), self.TEXT)
+
+    def testWriteBytesIO(self):
+        # "Test BZ2File.write() with BytesIO destination"
+        with BytesIO() as bio:
+            with BZ2File(fileobj=bio, mode="w") as bz2f:
+                self.assertRaises(TypeError, bz2f.write)
+                bz2f.write(self.TEXT)
+            self.assertEqual(self.decompress(bio.getvalue()), self.TEXT)
+            self.assertFalse(bio.closed)
+
+    def testSeekForwardBytesIO(self):
+        # "Test BZ2File.seek(150, 0) with BytesIO source"
+        with BytesIO(self.getData()) as bio:
+            with BZ2File(fileobj=bio) as bz2f:
+                self.assertRaises(TypeError, bz2f.seek)
+                bz2f.seek(150)
+                self.assertEqual(bz2f.read(), self.TEXT[150:])
+
+    def testSeekBackwardsBytesIO(self):
+        # "Test BZ2File.seek(-150, 1) with BytesIO source"
+        with BytesIO(self.getData()) as bio:
+            with BZ2File(fileobj=bio) as bz2f:
+                bz2f.read(500)
+                bz2f.seek(-150, 1)
+                self.assertEqual(bz2f.read(), self.TEXT[500-150:])
 
 class BZ2CompressorTest(BaseTest):
     def testCompress(self):