Index: Doc/lib/libfileinput.tex
===================================================================
--- Doc/lib/libfileinput.tex	(revision 52964)
+++ Doc/lib/libfileinput.tex	(working copy)
@@ -52,7 +52,7 @@
 The following function is the primary interface of this module:
 
 \begin{funcdesc}{input}{\optional{files\optional{, inplace\optional{,
-                        backup\optional{, mode\optional{, openhook}}}}}}
+                        backup\optional{, mode\optional{, openhook\optional{, write_mode}}}}}}}
   Create an instance of the \class{FileInput} class.  The instance
   will be used as global state for the functions of this module, and
   is also returned to use during iteration.  The parameters to this
@@ -123,7 +123,7 @@
 
 \begin{classdesc}{FileInput}{\optional{files\optional{,
                              inplace\optional{, backup\optional{,
-                             mode\optional{, openhook}}}}}}
+                             mode\optional{, openhook\optional{, write_mode}}}}}}}
   Class \class{FileInput} is the implementation; its methods
   \method{filename()}, \method{fileno()}, \method{lineno()},
   \method{fileline()}, \method{isfirstline()}, \method{isstdin()},
@@ -139,6 +139,10 @@
   \function{open()}. It must be one of \code{'r'}, \code{'rU'},
   \code{'U'} and \code{'rb'}.
 
+  With \var{write_mode} you can specify the mode which is passed to the 
+  \function{open()} for the input file when writing in in-place mode. It must 
+  be either \code{'w'} (the default) or \code{'wb'}.
+
   The \var{openhook}, when given, must be a function that takes two arguments,
   \var{filename} and \var{mode}, and returns an accordingly opened
   file-like object.
@@ -156,8 +160,9 @@
 in place.  If the keyword argument \code{\var{backup}='.<some
 extension>'} is also given, it specifies the extension for the backup
 file, and the backup file remains around; by default, the extension is
-\code{'.bak'} and it is deleted when the output file is closed.  In-place
-filtering is disabled when standard input is read.
+\code{'.bak'} and it is deleted when the output file is closed. The write 
+mode for in-place filtering can be set using the \code{\var{write_mode}}
+keyword argument. In-place filtering is disabled when standard input is read.
 
 \strong{Caveat:} The current implementation does not work for MS-DOS
 8+3 filesystems.
Index: Lib/fileinput.py
===================================================================
--- Lib/fileinput.py	(revision 52964)
+++ Lib/fileinput.py	(working copy)
@@ -60,9 +60,11 @@
 in place.  If the keyword argument backup=".<some extension>" is also
 given, it specifies the extension for the backup file, and the backup
 file remains around; by default, the extension is ".bak" and it is
-deleted when the output file is closed.  In-place filtering is
-disabled when standard input is read.  XXX The current implementation
-does not work for MS-DOS 8+3 filesystems.
+deleted when the output file is closed.  The input file is by default
+written to in 'w' mode, this can be changed using the keyword argument 
+write_mode="<mode>" where mode must be one of 'w' or 'wb'. In-place 
+filtering is disabled when standard input is read.  XXX The current 
+implementation does not work for MS-DOS 8+3 filesystems.
 
 Performance: this module is unfortunately one of the slower ways of
 processing large numbers of input lines.  Nevertheless, a significant
@@ -89,8 +91,8 @@
 DEFAULT_BUFSIZE = 8*1024
 
 def input(files=None, inplace=0, backup="", bufsize=0,
-          mode="r", openhook=None):
-    """input([files[, inplace[, backup[, mode[, openhook]]]]])
+          mode="r", openhook=None, write_mode='w'):
+    """input([files[, inplace[, backup[, mode[, openhook[, write_mode]]]]]])
 
     Create an instance of the FileInput class. The instance will be used
     as global state for the functions of this module, and is also returned
@@ -100,7 +102,7 @@
     global _state
     if _state and _state._file:
         raise RuntimeError, "input() already active"
-    _state = FileInput(files, inplace, backup, bufsize, mode, openhook)
+    _state = FileInput(files, inplace, backup, bufsize, mode, openhook, write_mode)
     return _state
 
 def close():
@@ -182,7 +184,7 @@
     return _state.isstdin()
 
 class FileInput:
-    """class FileInput([files[, inplace[, backup[, mode[, openhook]]]]])
+    """class FileInput([files[, inplace[, backup[, mode[, openhook[, write_mode]]]]]])
 
     Class FileInput is the implementation of the module; its methods
     filename(), lineno(), fileline(), isfirstline(), isstdin(), fileno(),
@@ -195,7 +197,7 @@
     """
 
     def __init__(self, files=None, inplace=0, backup="", bufsize=0,
-                 mode="r", openhook=None):
+                 mode="r", openhook=None, write_mode="w"):
         if isinstance(files, basestring):
             files = (files,)
         else:
@@ -224,6 +226,12 @@
             raise ValueError("FileInput opening mode must be one of "
                              "'r', 'rU', 'U' and 'rb'")
         self._mode = mode
+        # restrict write_mode argument to writing modes
+        if inplace and write_mode not in ('w', 'wb'):
+            raise ValueError("FileInput write mode must be one of "
+                             "'w', 'wb'")
+        self._write_mode = write_mode
+
         if inplace and openhook:
             raise ValueError("FileInput cannot use an opening hook in inplace mode")
         elif openhook and not callable(openhook):
@@ -324,12 +332,15 @@
                     try:
                         perm = os.fstat(self._file.fileno()).st_mode
                     except OSError:
-                        self._output = open(self._filename, "w")
+                        self._output = open(self._filename, self._write_mode)
                     else:
+                        write_flags = os.O_CREAT | os.O_WRONLY | os.O_TRUNC
+                        if "b" in self._write_mode:
+                            write_flags = write_flags | os.O_BINARY
                         fd = os.open(self._filename,
-                                     os.O_CREAT | os.O_WRONLY | os.O_TRUNC,
+                                     write_flags,
                                      perm)
-                        self._output = os.fdopen(fd, "w")
+                        self._output = os.fdopen(fd, self._write_mode)
                         try:
                             if hasattr(os, 'chmod'):
                                 os.chmod(self._filename, perm)
Index: Lib/test/test_fileinput.py
===================================================================
--- Lib/test/test_fileinput.py	(revision 52964)
+++ Lib/test/test_fileinput.py	(working copy)
@@ -3,8 +3,8 @@
 Nick Mathewson
 '''
 
-from test.test_support import verify, verbose, TESTFN, TestFailed
-import sys, os, re
+from test.test_support import verify, verbose, TESTFN, TestFailed, run_unittest
+import sys, os, re, unittest
 from StringIO import StringIO
 from fileinput import FileInput, hook_encoded
 
@@ -15,6 +15,7 @@
 
 # Write lines (a list of lines) to temp file number i, and return the
 # temp file's name.
+
 def writeTmp(i, lines, mode='w'):  # opening in text mode is the default
     name = TESTFN + str(i)
     f = open(name, mode)
@@ -22,7 +23,6 @@
     f.close()
     return name
 
-pat = re.compile(r'LINE (\d+) OF FILE (\d+)')
 
 def remove_tempfiles(*names):
     for name in names:
@@ -31,197 +31,281 @@
         except:
             pass
 
-def runTests(t1, t2, t3, t4, bs=0, round=0):
-    start = 1 + round*6
-    if verbose:
-        print '%s. Simple iteration (bs=%s)' % (start+0, bs)
-    fi = FileInput(files=(t1, t2, t3, t4), bufsize=bs)
-    lines = list(fi)
-    fi.close()
-    verify(len(lines) == 31)
-    verify(lines[4] == 'Line 5 of file 1\n')
-    verify(lines[30] == 'Line 1 of file 4\n')
-    verify(fi.lineno() == 31)
-    verify(fi.filename() == t4)
+def writeFiles():
+    t1 = writeTmp(1, ["Line %s of file 1\n" % (i+1) for i in range(15)])
+    t2 = writeTmp(2, ["Line %s of file 2\n" % (i+1) for i in range(10)])
+    t3 = writeTmp(3, ["Line %s of file 3\n" % (i+1) for i in range(5)])
+    t4 = writeTmp(4, ["Line %s of file 4\n" % (i+1) for i in range(1)])
 
-    if verbose:
-        print '%s. Status variables (bs=%s)' % (start+1, bs)
-    fi = FileInput(files=(t1, t2, t3, t4), bufsize=bs)
-    s = "x"
-    while s and s != 'Line 6 of file 2\n':
-        s = fi.readline()
-    verify(fi.filename() == t2)
-    verify(fi.lineno() == 21)
-    verify(fi.filelineno() == 6)
-    verify(not fi.isfirstline())
-    verify(not fi.isstdin())
+    return (t1, t2, t3, t4)
 
-    if verbose:
-        print '%s. Nextfile (bs=%s)' % (start+2, bs)
-    fi.nextfile()
-    verify(fi.readline() == 'Line 1 of file 3\n')
-    verify(fi.lineno() == 22)
-    fi.close()
+class FileInputTests(unittest.TestCase):
+    
+    def testInplaceBinaryMode(self):
+        '''Check that the binary write mode works correctly.
+        Write LF characters, and ensure that they are not translated to 
+        CRLF or LF (irrelevant test on unix type systems, since binary and
+        text mode are the same.'''
+        test_files = ()
+        try:
+            test_files = writeFiles()
+            fi = FileInput(test_files, inplace=True, write_mode="wb")
+            
+            for line in fi:
+                print line.strip(), "\n"
 
-    if verbose:
-        print '%s. Stdin (bs=%s)' % (start+3, bs)
-    fi = FileInput(files=(t1, t2, t3, t4, '-'), bufsize=bs)
-    savestdin = sys.stdin
-    try:
-        sys.stdin = StringIO("Line 1 of stdin\nLine 2 of stdin\n")
+            fi.close()
+
+            fi = FileInput(test_files)
+
+            for line in fi:
+                self.assert_('\r' not in line)
+            fi.close()
+        finally:
+            remove_tempfiles(*test_files)
+    
+    def testZeroLengthFiles(self):
+        '''Check for proper behavior with 0-byte files.'''
+        try:
+            t1 = writeTmp(1, [""])
+            t2 = writeTmp(2, [""])
+            t3 = writeTmp(3, ["The only line there is.\n"])
+            t4 = writeTmp(4, [""])
+            fi = FileInput(files=(t1, t2, t3, t4))
+            line = fi.readline()
+            self.assert_(line == 'The only line there is.\n')
+            self.assert_(fi.lineno() == 1)
+            self.assert_(fi.filelineno() == 1)
+            self.assert_(fi.filename() == t3)
+            line = fi.readline()
+            self.assert_(not line)
+            self.assert_(fi.lineno() == 1)
+            self.assert_(fi.filelineno() == 0)
+            self.assert_(fi.filename() == t4)
+            fi.close()
+        finally:
+            remove_tempfiles(t1, t2, t3, t4)
+
+    def testNoNewlinesAtEnd(self):
+        "Files that don't end with newline"
+        try:
+            t1 = writeTmp(1, ["A\nB\nC"])
+            t2 = writeTmp(2, ["D\nE\nF"])
+            fi = FileInput(files=(t1, t2))
+            lines = list(fi)
+            self.assert_(lines == ["A\n", "B\n", "C", "D\n", "E\n", "F"])
+            self.assert_(fi.filelineno() == 3)
+            self.assert_(fi.lineno() == 6)
+        finally:
+            remove_tempfiles(t1, t2)
+
+    def testUnicodeFilenames(self):
+        "Unicode filenames"
+        try:
+            t1 = writeTmp(1, ["A\nB"])
+            encoding = sys.getfilesystemencoding()
+            if encoding is None:
+                encoding = 'ascii'
+            fi = FileInput(files=unicode(t1, encoding))
+            lines = list(fi)
+            self.assert_(lines == ["A\n", "B"])
+        finally:
+            remove_tempfiles(t1)
+
+    def testFileno(self):
+        "Test correct fileno() operation."
+        try:
+            t1 = writeTmp(1, ["A\nB"])
+            t2 = writeTmp(2, ["C\nD"])
+            fi = FileInput(files=(t1, t2))
+            self.assert_(fi.fileno() == -1)
+            line = fi.next()
+            self.assert_(fi.fileno() != -1)
+            fi.nextfile()
+            self.assert_(fi.fileno() == -1)
+            line = list(fi)
+            self.assert_(fi.fileno() == -1)
+        finally:
+            remove_tempfiles(t1, t2)
+
+    def testFileOpeningHook(self):
+        "Test file opening hook"
+        try:
+            # cannot use openhook and inplace mode
+            fi = FileInput(inplace=1, openhook=lambda f,m: None)
+            self.fail("FileInput should raise if both inplace "
+                             "and openhook arguments are given")
+        except ValueError:
+            pass
+        try:
+            fi = FileInput(openhook=1)
+            self.fail("FileInput should check openhook for being callable")
+        except ValueError:
+            pass
+        try:
+            t1 = writeTmp(1, ["A\nB"], mode="wb")
+            fi = FileInput(files=t1, openhook=hook_encoded("rot13"))
+            lines = list(fi)
+            self.assert_(lines == ["N\n", "O"])
+        finally:
+            remove_tempfiles(t1)
+
+class DefaultBufferSizeTests(unittest.TestCase):
+    def setUp(self):
+        self.test_files = writeFiles()
+        self.bs = 0
+
+    def tearDown(self):
+        remove_tempfiles(*self.test_files)
+
+    def testSimpleIteration(self):
+        "Simple iteration (bs=0)"
+
+        fi = FileInput(files=self.test_files, bufsize=self.bs)
         lines = list(fi)
-        verify(len(lines) == 33)
-        verify(lines[32] == 'Line 2 of stdin\n')
-        verify(fi.filename() == '<stdin>')
+        fi.close()
+        self.assert_(len(lines) == 31)
+        self.assert_(lines[4] == 'Line 5 of file 1\n')
+        self.assert_(lines[30] == 'Line 1 of file 4\n')
+        self.assert_(fi.lineno() == 31)
+        self.assert_(fi.filename() == self.test_files[3])
+
+    def testStatusVariables(self):
+        'Status variables (bs=0)'
+
+        fi = FileInput(files=self.test_files, bufsize=self.bs)
+        s = "x"
+        while s and s != 'Line 6 of file 2\n':
+            s = fi.readline()
+        self.assert_(fi.filename() == self.test_files[1])
+        self.assert_(fi.lineno() == 21)
+        self.assert_(fi.filelineno() == 6)
+        self.assert_(not fi.isfirstline())
+        self.assert_(not fi.isstdin())
+        fi.close()
+
+    def testNextFile(self):
+        'Nextfile (bs=0)'
+
+        fi = FileInput(files=self.test_files, bufsize=self.bs)
+
+        for i in range(1,4):
+            fi.nextfile() # Does nothing on the first iteration, as no lines have been read.
+            line = fi.readline()
+            self.assert_(line == "Line 1 of file %d\n" % i)
+
+        # Three lines have been read - lines skipped do not count toward the cumulative total.
+        self.assert_(fi.lineno() == 3)
+        fi.close()
+
+    def testStdIn(self):
+        'Stdin (bs=0)'
+        file_list = list(self.test_files)
+        file_list.append('-')
+
+        fi = FileInput(files=file_list, bufsize=self.bs)
+        savestdin = sys.stdin
+        try:
+            sys.stdin = StringIO("Line 1 of stdin\nLine 2 of stdin\n")
+            lines = list(fi)
+            self.assert_(len(lines) == 33)
+            self.assert_(lines[32] == 'Line 2 of stdin\n')
+            self.assert_(fi.filename() == '<stdin>')
+            fi.nextfile()
+        finally:
+            sys.stdin = savestdin
+            fi.close()
+
+    def testBoundaryConditions(self):
+        'Boundary conditions (bs=0)'
+
+        fi = FileInput(files=self.test_files, bufsize=self.bs)
+        self.assert_(fi.lineno() == 0)
+        self.assert_(fi.filename() == None)
         fi.nextfile()
-    finally:
-        sys.stdin = savestdin
+        self.assert_(fi.lineno() == 0)
+        self.assert_(fi.filename() == None)
+        fi.close()
 
-    if verbose:
-        print '%s. Boundary conditions (bs=%s)' % (start+4, bs)
-    fi = FileInput(files=(t1, t2, t3, t4), bufsize=bs)
-    verify(fi.lineno() == 0)
-    verify(fi.filename() == None)
-    fi.nextfile()
-    verify(fi.lineno() == 0)
-    verify(fi.filename() == None)
+    def testInplace(self):
+        'Inplace (bs=0)'
 
-    if verbose:
-        print '%s. Inplace (bs=%s)' % (start+5, bs)
-    savestdout = sys.stdout
-    try:
-        fi = FileInput(files=(t1, t2, t3, t4), inplace=1, bufsize=bs)
+        savestdout = sys.stdout
+        try:
+            fi = FileInput(files=self.test_files, inplace=1, bufsize=self.bs)
+            for line in fi:
+                line = line[:-1].upper()
+                print line
+            fi.close()
+        finally:
+            sys.stdout = savestdout
+
+        pat = re.compile(r'LINE (\d+) OF FILE (\d+)')
+
+        fi = FileInput(files=self.test_files, bufsize=self.bs)
         for line in fi:
-            line = line[:-1].upper()
-            print line
+            self.assert_(line[-1] == '\n')
+            m = pat.match(line[:-1])
+            self.assert_(m != None)
+            self.assert_(int(m.group(1)) == fi.filelineno())
         fi.close()
-    finally:
-        sys.stdout = savestdout
 
-    fi = FileInput(files=(t1, t2, t3, t4), bufsize=bs)
-    for line in fi:
-        verify(line[-1] == '\n')
-        m = pat.match(line[:-1])
-        verify(m != None)
-        verify(int(m.group(1)) == fi.filelineno())
-    fi.close()
+    def testOpeningMode(self):
+        "Specify opening mode (bs=0)"
+        try:
+            # invalid mode, should raise ValueError
+            fi = FileInput(mode="w")
+            self.fail("FileInput should reject invalid mode argument")
+        except ValueError:
+            pass
+        try:
+            # try opening in universal newline mode
+            t1 = writeTmp(1, ["A\nB\r\nC\rD"], mode="wb")
+            fi = FileInput(files=t1, mode="U")
+            lines = list(fi)
+            self.assert_(lines == ["A\n", "B\n", "C\n", "D"])
+        finally:
+            remove_tempfiles(t1)
 
 
-def writeFiles():
-    global t1, t2, t3, t4
-    t1 = writeTmp(1, ["Line %s of file 1\n" % (i+1) for i in range(15)])
-    t2 = writeTmp(2, ["Line %s of file 2\n" % (i+1) for i in range(10)])
-    t3 = writeTmp(3, ["Line %s of file 3\n" % (i+1) for i in range(5)])
-    t4 = writeTmp(4, ["Line %s of file 4\n" % (i+1) for i in range(1)])
+class SmallBufferSizeTests(DefaultBufferSizeTests):
+    def setUp(self):
+        self.test_files = writeFiles()
+        self.bs = 30
 
-# First, run the tests with default and teeny buffer size.
-for round, bs in (0, 0), (1, 30):
-    try:
-        writeFiles()
-        runTests(t1, t2, t3, t4, bs, round)
-    finally:
-        remove_tempfiles(t1, t2, t3, t4)
+    def testSimpleIteration(self):
+        "Simple iteration (bs=30)"
+        DefaultBufferSizeTests.testSimpleIteration(self)
 
-# Next, check for proper behavior with 0-byte files.
-if verbose:
-    print "13. 0-byte files"
-try:
-    t1 = writeTmp(1, [""])
-    t2 = writeTmp(2, [""])
-    t3 = writeTmp(3, ["The only line there is.\n"])
-    t4 = writeTmp(4, [""])
-    fi = FileInput(files=(t1, t2, t3, t4))
-    line = fi.readline()
-    verify(line == 'The only line there is.\n')
-    verify(fi.lineno() == 1)
-    verify(fi.filelineno() == 1)
-    verify(fi.filename() == t3)
-    line = fi.readline()
-    verify(not line)
-    verify(fi.lineno() == 1)
-    verify(fi.filelineno() == 0)
-    verify(fi.filename() == t4)
-    fi.close()
-finally:
-    remove_tempfiles(t1, t2, t3, t4)
+    def testStatusVariables(self):
+        'Status variables (bs=30)'
+        DefaultBufferSizeTests.testStatusVariables(self)
 
-if verbose:
-    print "14. Files that don't end with newline"
-try:
-    t1 = writeTmp(1, ["A\nB\nC"])
-    t2 = writeTmp(2, ["D\nE\nF"])
-    fi = FileInput(files=(t1, t2))
-    lines = list(fi)
-    verify(lines == ["A\n", "B\n", "C", "D\n", "E\n", "F"])
-    verify(fi.filelineno() == 3)
-    verify(fi.lineno() == 6)
-finally:
-    remove_tempfiles(t1, t2)
+    def testNextFile(self):
+        'Nextfile (bs=30)'
+        DefaultBufferSizeTests.testNextFile(self)
 
-if verbose:
-    print "15. Unicode filenames"
-try:
-    t1 = writeTmp(1, ["A\nB"])
-    encoding = sys.getfilesystemencoding()
-    if encoding is None:
-        encoding = 'ascii'
-    fi = FileInput(files=unicode(t1, encoding))
-    lines = list(fi)
-    verify(lines == ["A\n", "B"])
-finally:
-    remove_tempfiles(t1)
+    def testStdIn(self):
+        'Stdin (bs=30)'
+        DefaultBufferSizeTests.testStdIn(self)
 
-if verbose:
-    print "16. fileno()"
-try:
-    t1 = writeTmp(1, ["A\nB"])
-    t2 = writeTmp(2, ["C\nD"])
-    fi = FileInput(files=(t1, t2))
-    verify(fi.fileno() == -1)
-    line = fi.next()
-    verify(fi.fileno() != -1)
-    fi.nextfile()
-    verify(fi.fileno() == -1)
-    line = list(fi)
-    verify(fi.fileno() == -1)
-finally:
-    remove_tempfiles(t1, t2)
+    def testBoundaryConditions(self):
+        'Boundary conditions (bs=30)'
+        DefaultBufferSizeTests.testBoundaryConditions(self)
 
-if verbose:
-    print "17. Specify opening mode"
-try:
-    # invalid mode, should raise ValueError
-    fi = FileInput(mode="w")
-    raise TestFailed("FileInput should reject invalid mode argument")
-except ValueError:
-    pass
-try:
-    # try opening in universal newline mode
-    t1 = writeTmp(1, ["A\nB\r\nC\rD"], mode="wb")
-    fi = FileInput(files=t1, mode="U")
-    lines = list(fi)
-    verify(lines == ["A\n", "B\n", "C\n", "D"])
-finally:
-    remove_tempfiles(t1)
+    def testInplace(self):
+        'Inplace (bs=30)'
+        DefaultBufferSizeTests.testInplace(self)
 
-if verbose:
-    print "18. Test file opening hook"
-try:
-    # cannot use openhook and inplace mode
-    fi = FileInput(inplace=1, openhook=lambda f,m: None)
-    raise TestFailed("FileInput should raise if both inplace "
-                     "and openhook arguments are given")
-except ValueError:
-    pass
-try:
-    fi = FileInput(openhook=1)
-    raise TestFailed("FileInput should check openhook for being callable")
-except ValueError:
-    pass
-try:
-    t1 = writeTmp(1, ["A\nB"], mode="wb")
-    fi = FileInput(files=t1, openhook=hook_encoded("rot13"))
-    lines = list(fi)
-    verify(lines == ["N\n", "O"])
-finally:
-    remove_tempfiles(t1)
+    def testOpeningMode(self):
+        "Specify opening mode (bs=30)"
+        DefaultBufferSizeTests.testOpeningMode(self)
+
+def test_main():
+    print "Running Unit Tests"
+    run_unittest(FileInputTests, DefaultBufferSizeTests, SmallBufferSizeTests)
+
+
+if __name__ == "__main__":
+    test_main()
+