diff --git a/Lib/test/test_zipfile.py b/Lib/test/test_zipfile.py
index 49602ff..3d2f9bd 100644
--- a/Lib/test/test_zipfile.py
+++ b/Lib/test/test_zipfile.py
@@ -14,12 +14,12 @@
 from test.test_support import TESTFN, run_unittest
 
 TESTFN2 = TESTFN + "2"
-FIXEDTEST_SIZE = 10
+FIXEDTEST_SIZE = 1000
 
 class TestsWithSourceFile(unittest.TestCase):
     def setUp(self):
-        self.line_gen = ("Zipfile test line %d. random float: %f" % (i, random())
-                          for i in xrange(FIXEDTEST_SIZE))
+        self.line_gen = ["Zipfile test line %d. random float: %f" % (i, random())
+                          for i in xrange(FIXEDTEST_SIZE)]
         self.data = '\n'.join(self.line_gen) + '\n'
 
         # Make a source file with some lines
@@ -239,6 +239,63 @@
         self.assertEqual(zipfp.namelist(), ["absolute"])
         zipfp.close()
 
+    def testAppendToZipFile(self):
+        # Test appending to an existing zipfile
+        zipfp = zipfile.ZipFile(TESTFN2, "w", zipfile.ZIP_STORED)
+        zipfp.write(TESTFN, TESTFN)
+        zipfp.close()
+        zipfp = zipfile.ZipFile(TESTFN2, "a", zipfile.ZIP_STORED)
+        zipfp.writestr("strfile", self.data)
+        self.assertEqual(zipfp.namelist(), [TESTFN, "strfile"])
+        zipfp.close()
+
+    def testAppendToNonZipFile(self):
+        # Test appending to an existing file that is not a zipfile
+        # NOTE: this test fails if len(d) < 22 because of the first
+        # line "fpin.seek(-22, 2)" in _EndRecData
+        d = 'I am not a ZipFile!'*10
+        f = file(TESTFN2, 'wb')
+        f.write(d)
+        f.close()
+        zipfp = zipfile.ZipFile(TESTFN2, "a", zipfile.ZIP_STORED)
+        zipfp.write(TESTFN, TESTFN)
+        zipfp.close()
+
+        f = file(TESTFN2, 'rb')
+        f.seek(len(d))
+        zipfp = zipfile.ZipFile(f, "r")
+        self.assertEqual(zipfp.namelist(), [TESTFN])
+        zipfp.close()
+        f.close()
+
+    def test_WriteDefaultName(self):
+        # Check that calling ZipFile.write without arcname specified produces the expected result
+        zipfp = zipfile.ZipFile(TESTFN2, "w")
+        zipfp.write(TESTFN)
+        self.assertEqual(zipfp.read(TESTFN), file(TESTFN).read())
+        zipfp.close()
+
+    def test_PerFileCompression(self):
+        # Check that files within a Zip archive can have different compression options
+        zipfp = zipfile.ZipFile(TESTFN2, "w")
+        zipfp.write(TESTFN, 'storeme', zipfile.ZIP_STORED)
+        zipfp.write(TESTFN, 'deflateme', zipfile.ZIP_DEFLATED)
+        sinfo = zipfp.getinfo('storeme')
+        dinfo = zipfp.getinfo('deflateme')
+        self.assertEqual(sinfo.compress_type, zipfile.ZIP_STORED)
+        self.assertEqual(dinfo.compress_type, zipfile.ZIP_DEFLATED)
+        zipfp.close()
+
+    def test_WriteToReadonly(self):
+        # Check that trying to call write() on a readonly ZipFile object
+        # raises a RuntimeError
+        zipf = zipfile.ZipFile(TESTFN2, mode="w")
+        zipf.writestr("somefile.txt", "bogus")
+        zipf.close()
+        zipf = zipfile.ZipFile(TESTFN2, mode="r")
+        self.assertRaises(RuntimeError, zipf.write, TESTFN)
+        zipf.close()
+
     def tearDown(self):
         os.remove(TESTFN)
         os.remove(TESTFN2)
@@ -361,7 +418,6 @@
         self.assertEqual(zipfp.namelist(), ["absolute"])
         zipfp.close()
 
-
     def tearDown(self):
         zipfile.ZIP64_LIMIT = self._limit
         os.remove(TESTFN)
@@ -432,6 +488,11 @@
         finally:
             shutil.rmtree(TESTFN2)
 
+    def testWriteNonPyfile(self):
+        zipfp  = zipfile.PyZipFile(TemporaryFile(), "w")
+        file(TESTFN, 'w').write('most definitely not a python file')
+        self.assertRaises(RuntimeError, zipfp.writepy, TESTFN)
+        os.remove(TESTFN)
 
 
 class OtherTests(unittest.TestCase):
@@ -513,7 +574,56 @@
         # a RuntimeError, and so should calling .testzip.  An earlier
         # version of .testzip would swallow this exception (and any other)
         # and report that the first file in the archive was corrupt.
+        self.assertRaises(RuntimeError, zipf.read, "foo.txt")
+        self.assertRaises(RuntimeError, zipf.open, "foo.txt")
         self.assertRaises(RuntimeError, zipf.testzip)
+        self.assertRaises(RuntimeError, zipf.writestr, "bogus.txt", "bogus")
+        file(TESTFN, 'w').write('zipfile test data')
+        self.assertRaises(RuntimeError, zipf.write, TESTFN)
+
+    def test_BadConstructorMode(self):
+        # Check that bad modes passed to ZipFile constructor are caught
+        self.assertRaises(RuntimeError, zipfile.ZipFile, TESTFN, "q")
+
+    def test_BadOpenMode(self):
+        # Check that bad modes passed to ZipFile.open are caught
+        zipf = zipfile.ZipFile(TESTFN, mode="w")
+        zipf.writestr("foo.txt", "O, for a Muse of Fire!")
+        zipf.close()
+        zipf = zipfile.ZipFile(TESTFN, mode="r")
+        # read the data to make sure the file is there
+        zipf.read("foo.txt")
+        self.assertRaises(RuntimeError, zipf.open, "foo.txt", "q")
+        zipf.close()
+
+    def test_Read0(self):
+        # Check that calling read(0) on a ZipExtFile object returns an empty
+        # string and doesn't advance file pointer
+        zipf = zipfile.ZipFile(TESTFN, mode="w")
+        zipf.writestr("foo.txt", "O, for a Muse of Fire!")
+        # read the data to make sure the file is there
+        f = zipf.open("foo.txt")
+        for i in xrange(FIXEDTEST_SIZE):
+            self.assertEqual(f.read(0), '')
+
+        self.assertEqual(f.read(), "O, for a Muse of Fire!")
+        zipf.close()
+
+    def test_OpenNonexistentItem(self):
+        # Check that attempting to call open() for an item that doesn't
+        # exist in the archive raises a RuntimeError
+        zipf = zipfile.ZipFile(TESTFN, mode="w")
+        self.assertRaises(KeyError, zipf.open, "foo.txt", "r")
+
+    def test_BadCompressionMode(self):
+        # Check that bad compression methods passed to ZipFile.open are caught
+        self.assertRaises(RuntimeError, zipfile.ZipFile, TESTFN, "w", -1)
+
+    def test_NullByteInFilename(self):
+        # Check that a filename containing a null byte is properly terminated
+        zipf = zipfile.ZipFile(TESTFN, mode="w")
+        zipf.writestr("foo.txt\x00qqq", "O, for a Muse of Fire!")
+        self.assertEqual(zipf.namelist(), ['foo.txt'])
 
     def tearDown(self):
         support.unlink(TESTFN)
diff --git a/Lib/zipfile.py b/Lib/zipfile.py
index 67d2c5d..a53f8ed 100644
--- a/Lib/zipfile.py
+++ b/Lib/zipfile.py
@@ -568,8 +568,9 @@
 
     def __init__(self, file, mode="r", compression=ZIP_STORED, allowZip64=False):
         """Open the ZIP file with mode read "r", write "w" or append "a"."""
-        self._allowZip64 = allowZip64
-        self._didModify = False
+        if mode not in ("r", "w", "a"):
+            raise RuntimeError('ZipFile() requires mode "r", "w", or "a"')
+
         if compression == ZIP_STORED:
             pass
         elif compression == ZIP_DEFLATED:
@@ -578,6 +579,9 @@
                       "Compression requires the (missing) zlib module"
         else:
             raise RuntimeError, "That compression method is not supported"
+
+        self._allowZip64 = allowZip64
+        self._didModify = False
         self.debug = 0  # Level of printing: 0 through 3
         self.NameToInfo = {}    # Find file info given name
         self.filelist = []      # List of ZipInfo instances for archive
@@ -720,7 +724,12 @@
 
     def getinfo(self, name):
         """Return the instance of ZipInfo given 'name'."""
-        return self.NameToInfo[name]
+        info = self.NameToInfo.get(name)
+        if info is None:
+            raise KeyError(
+                'There is no item named %r in the archive' % name)
+
+        return info
 
     def setpassword(self, pwd):
         """Set default password for encrypted files."""
@@ -824,6 +833,10 @@
     def write(self, filename, arcname=None, compress_type=None):
         """Put the bytes from filename into the archive under the name
         arcname."""
+        if not self.fp:
+            raise RuntimeError(
+                  "Attempt to write to ZIP archive that was already closed")
+
         st = os.stat(filename)
         mtime = time.localtime(st.st_mtime)
         date_time = mtime[0:6]
@@ -896,6 +909,11 @@
             zinfo.compress_type = self.compression
         else:
             zinfo = zinfo_or_arcname
+
+        if not self.fp:
+            raise RuntimeError(
+                  "Attempt to write to ZIP archive that was already closed")
+
         zinfo.file_size = len(bytes)            # Uncompressed size
         zinfo.header_offset = self.fp.tell()    # Start of header bytes
         self._writecheck(zinfo)