bpo-33753: Refactor creating temporary files in test_fileinput. (GH-7377)

(cherry picked from commit 5f48e26)

Co-authored-by: Serhiy Storchaka <[email protected]>

Author: miss-islington

Lib/test/test_fileinput.py

@@ -8,6 +8,7 @@
 import fileinput
 import collections
 import builtins
+import tempfile
 import unittest
 
 try:
@@ -33,20 +34,15 @@
 # all the work, and a few functions (input, etc.) that use a global _state
 # variable.
 
-# 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)
-    for line in lines:
-        f.write(line)
-    f.close()
-    return name
-
-def remove_tempfiles(*names):
-    for name in names:
-        if name:
-            safe_unlink(name)
+class BaseTests:
+    # Write a content (str or bytes) to temp file, and return the
+    # temp file's name.
+    def writeTmp(self, content, *, mode='w'):  # opening in text mode is the default
+        fd, name = tempfile.mkstemp()
+        self.addCleanup(support.unlink, name)
+        with open(fd, mode) as f:
+            f.write(content)
+        return name
 
 class LineReader:
 
@@ -84,23 +80,19 @@ def readlines(self, hint=-1):
     def close(self):
         pass
 
-class BufferSizesTests(unittest.TestCase):
+class BufferSizesTests(BaseTests, unittest.TestCase):
     def test_buffer_sizes(self):
         # First, run the tests with default and teeny buffer size.
         for round, bs in (0, 0), (1, 30):
-            t1 = t2 = t3 = t4 = None
-            try:
-                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 bs:
-                    with self.assertWarns(DeprecationWarning):
-                        self.buffer_size_test(t1, t2, t3, t4, bs, round)
-                else:
+            t1 = self.writeTmp(''.join("Line %s of file 1\n" % (i+1) for i in range(15)))
+            t2 = self.writeTmp(''.join("Line %s of file 2\n" % (i+1) for i in range(10)))
+            t3 = self.writeTmp(''.join("Line %s of file 3\n" % (i+1) for i in range(5)))
+            t4 = self.writeTmp(''.join("Line %s of file 4\n" % (i+1) for i in range(1)))
+            if bs:
+                with self.assertWarns(DeprecationWarning):
                     self.buffer_size_test(t1, t2, t3, t4, bs, round)
-            finally:
-                remove_tempfiles(t1, t2, t3, t4)
+            else:
+                self.buffer_size_test(t1, t2, t3, t4, bs, round)
 
     def buffer_size_test(self, t1, t2, t3, t4, bs=0, round=0):
         pat = re.compile(r'LINE (\d+) OF FILE (\d+)')
@@ -187,74 +179,59 @@ def __call__(self, *args, **kwargs):
         self.invoked = True
         raise self.exception_type()
 
-class FileInputTests(unittest.TestCase):
+class FileInputTests(BaseTests, unittest.TestCase):
 
     def test_zero_byte_files(self):
-        t1 = t2 = t3 = t4 = None
-        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.assertEqual(line, 'The only line there is.\n')
-            self.assertEqual(fi.lineno(), 1)
-            self.assertEqual(fi.filelineno(), 1)
-            self.assertEqual(fi.filename(), t3)
-
-            line = fi.readline()
-            self.assertFalse(line)
-            self.assertEqual(fi.lineno(), 1)
-            self.assertEqual(fi.filelineno(), 0)
-            self.assertEqual(fi.filename(), t4)
-            fi.close()
-        finally:
-            remove_tempfiles(t1, t2, t3, t4)
+        t1 = self.writeTmp("")
+        t2 = self.writeTmp("")
+        t3 = self.writeTmp("The only line there is.\n")
+        t4 = self.writeTmp("")
+        fi = FileInput(files=(t1, t2, t3, t4))
+
+        line = fi.readline()
+        self.assertEqual(line, 'The only line there is.\n')
+        self.assertEqual(fi.lineno(), 1)
+        self.assertEqual(fi.filelineno(), 1)
+        self.assertEqual(fi.filename(), t3)
+
+        line = fi.readline()
+        self.assertFalse(line)
+        self.assertEqual(fi.lineno(), 1)
+        self.assertEqual(fi.filelineno(), 0)
+        self.assertEqual(fi.filename(), t4)
+        fi.close()
 
     def test_files_that_dont_end_with_newline(self):
-        t1 = t2 = None
-        try:
-            t1 = writeTmp(1, ["A\nB\nC"])
-            t2 = writeTmp(2, ["D\nE\nF"])
-            fi = FileInput(files=(t1, t2))
-            lines = list(fi)
-            self.assertEqual(lines, ["A\n", "B\n", "C", "D\n", "E\n", "F"])
-            self.assertEqual(fi.filelineno(), 3)
-            self.assertEqual(fi.lineno(), 6)
-        finally:
-            remove_tempfiles(t1, t2)
+        t1 = self.writeTmp("A\nB\nC")
+        t2 = self.writeTmp("D\nE\nF")
+        fi = FileInput(files=(t1, t2))
+        lines = list(fi)
+        self.assertEqual(lines, ["A\n", "B\n", "C", "D\n", "E\n", "F"])
+        self.assertEqual(fi.filelineno(), 3)
+        self.assertEqual(fi.lineno(), 6)
 
 ##     def test_unicode_filenames(self):
 ##         # XXX A unicode string is always returned by writeTmp.
 ##         #     So is this needed?
-##         try:
-##             t1 = writeTmp(1, ["A\nB"])
-##             encoding = sys.getfilesystemencoding()
-##             if encoding is None:
-##                 encoding = 'ascii'
-##             fi = FileInput(files=str(t1, encoding))
-##             lines = list(fi)
-##             self.assertEqual(lines, ["A\n", "B"])
-##         finally:
-##             remove_tempfiles(t1)
+##         t1 = self.writeTmp("A\nB")
+##         encoding = sys.getfilesystemencoding()
+##         if encoding is None:
+##             encoding = 'ascii'
+##         fi = FileInput(files=str(t1, encoding))
+##         lines = list(fi)
+##         self.assertEqual(lines, ["A\n", "B"])
 
     def test_fileno(self):
-        t1 = t2 = None
-        try:
-            t1 = writeTmp(1, ["A\nB"])
-            t2 = writeTmp(2, ["C\nD"])
-            fi = FileInput(files=(t1, t2))
-            self.assertEqual(fi.fileno(), -1)
-            line =next( fi)
-            self.assertNotEqual(fi.fileno(), -1)
-            fi.nextfile()
-            self.assertEqual(fi.fileno(), -1)
-            line = list(fi)
-            self.assertEqual(fi.fileno(), -1)
-        finally:
-            remove_tempfiles(t1, t2)
+        t1 = self.writeTmp("A\nB")
+        t2 = self.writeTmp("C\nD")
+        fi = FileInput(files=(t1, t2))
+        self.assertEqual(fi.fileno(), -1)
+        line = next(fi)
+        self.assertNotEqual(fi.fileno(), -1)
+        fi.nextfile()
+        self.assertEqual(fi.fileno(), -1)
+        line = list(fi)
+        self.assertEqual(fi.fileno(), -1)
 
     def test_opening_mode(self):
         try:
@@ -263,17 +240,13 @@ def test_opening_mode(self):
             self.fail("FileInput should reject invalid mode argument")
         except ValueError:
             pass
-        t1 = None
-        try:
-            # try opening in universal newline mode
-            t1 = writeTmp(1, [b"A\nB\r\nC\rD"], mode="wb")
-            with check_warnings(('', DeprecationWarning)):
-                fi = FileInput(files=t1, mode="U")
-            with check_warnings(('', DeprecationWarning)):
-                lines = list(fi)
-            self.assertEqual(lines, ["A\n", "B\n", "C\n", "D"])
-        finally:
-            remove_tempfiles(t1)
+        # try opening in universal newline mode
+        t1 = self.writeTmp(b"A\nB\r\nC\rD", mode="wb")
+        with check_warnings(('', DeprecationWarning)):
+            fi = FileInput(files=t1, mode="U")
+        with check_warnings(('', DeprecationWarning)):
+            lines = list(fi)
+        self.assertEqual(lines, ["A\n", "B\n", "C\n", "D"])
 
     def test_stdin_binary_mode(self):
         with mock.patch('sys.stdin') as m_stdin:
@@ -314,8 +287,7 @@ def __call__(self, *args):
                 self.invoked = True
                 return open(*args)
 
-        t = writeTmp(1, ["\n"])
-        self.addCleanup(remove_tempfiles, t)
+        t = self.writeTmp("\n")
         custom_open_hook = CustomOpenHook()
         with FileInput([t], openhook=custom_open_hook) as fi:
             fi.readline()
@@ -358,27 +330,22 @@ def test_readline_binary_mode(self):
             self.assertEqual(fi.readline(), b'')
 
     def test_context_manager(self):
-        try:
-            t1 = writeTmp(1, ["A\nB\nC"])
-            t2 = writeTmp(2, ["D\nE\nF"])
-            with FileInput(files=(t1, t2)) as fi:
-                lines = list(fi)
-            self.assertEqual(lines, ["A\n", "B\n", "C", "D\n", "E\n", "F"])
-            self.assertEqual(fi.filelineno(), 3)
-            self.assertEqual(fi.lineno(), 6)
-            self.assertEqual(fi._files, ())
-        finally:
-            remove_tempfiles(t1, t2)
+        t1 = self.writeTmp("A\nB\nC")
+        t2 = self.writeTmp("D\nE\nF")
+        with FileInput(files=(t1, t2)) as fi:
+            lines = list(fi)
+        self.assertEqual(lines, ["A\n", "B\n", "C", "D\n", "E\n", "F"])
+        self.assertEqual(fi.filelineno(), 3)
+        self.assertEqual(fi.lineno(), 6)
+        self.assertEqual(fi._files, ())
 
     def test_close_on_exception(self):
+        t1 = self.writeTmp("")
         try:
-            t1 = writeTmp(1, [""])
             with FileInput(files=t1) as fi:
                 raise OSError
         except OSError:
             self.assertEqual(fi._files, ())
-        finally:
-            remove_tempfiles(t1)
 
     def test_empty_files_list_specified_to_constructor(self):
         with FileInput(files=[]) as fi:
@@ -387,8 +354,7 @@ def test_empty_files_list_specified_to_constructor(self):
     def test__getitem__(self):
         """Tests invoking FileInput.__getitem__() with the current
            line number"""
-        t = writeTmp(1, ["line1\n", "line2\n"])
-        self.addCleanup(remove_tempfiles, t)
+        t = self.writeTmp("line1\nline2\n")
         with FileInput(files=[t]) as fi:
             retval1 = fi[0]
             self.assertEqual(retval1, "line1\n")
@@ -398,8 +364,7 @@ def test__getitem__(self):
     def test__getitem__invalid_key(self):
         """Tests invoking FileInput.__getitem__() with an index unequal to
            the line number"""
-        t = writeTmp(1, ["line1\n", "line2\n"])
-        self.addCleanup(remove_tempfiles, t)
+        t = self.writeTmp("line1\nline2\n")
         with FileInput(files=[t]) as fi:
             with self.assertRaises(RuntimeError) as cm:
                 fi[1]
@@ -408,8 +373,7 @@ def test__getitem__invalid_key(self):
     def test__getitem__eof(self):
         """Tests invoking FileInput.__getitem__() with the line number but at
            end-of-input"""
-        t = writeTmp(1, [])
-        self.addCleanup(remove_tempfiles, t)
+        t = self.writeTmp('')
         with FileInput(files=[t]) as fi:
             with self.assertRaises(IndexError) as cm:
                 fi[0]
@@ -423,8 +387,8 @@ def test_nextfile_oserror_deleting_backup(self):
         os_unlink_orig = os.unlink
         os_unlink_replacement = UnconditionallyRaise(OSError)
         try:
-            t = writeTmp(1, ["\n"])
-            self.addCleanup(remove_tempfiles, t)
+            t = self.writeTmp("\n")
+            self.addCleanup(support.unlink, t + '.bak')
             with FileInput(files=[t], inplace=True) as fi:
                 next(fi) # make sure the file is opened
                 os.unlink = os_unlink_replacement
@@ -443,8 +407,7 @@ def test_readline_os_fstat_raises_OSError(self):
         os_fstat_orig = os.fstat
         os_fstat_replacement = UnconditionallyRaise(OSError)
         try:
-            t = writeTmp(1, ["\n"])
-            self.addCleanup(remove_tempfiles, t)
+            t = self.writeTmp("\n")
             with FileInput(files=[t], inplace=True) as fi:
                 os.fstat = os_fstat_replacement
                 fi.readline()
@@ -463,8 +426,7 @@ def test_readline_os_chmod_raises_OSError(self):
         os_chmod_orig = os.chmod
         os_chmod_replacement = UnconditionallyRaise(OSError)
         try:
-            t = writeTmp(1, ["\n"])
-            self.addCleanup(remove_tempfiles, t)
+            t = self.writeTmp("\n")
             with FileInput(files=[t], inplace=True) as fi:
                 os.chmod = os_chmod_replacement
                 fi.readline()
@@ -483,8 +445,7 @@ def fileno(self):
                 self.__call__()
 
         unconditionally_raise_ValueError = FilenoRaisesValueError()
-        t = writeTmp(1, ["\n"])
-        self.addCleanup(remove_tempfiles, t)
+        t = self.writeTmp("\n")
         with FileInput(files=[t]) as fi:
             file_backup = fi._file
             try:
@@ -532,30 +493,22 @@ def test_iteration_buffering(self):
             self.assertEqual(src.linesread, [])
 
     def test_pathlib_file(self):
-        t1 = None
-        try:
-            t1 = Path(writeTmp(1, ["Pathlib file."]))
-            with FileInput(t1) as fi:
-                line = fi.readline()
-                self.assertEqual(line, 'Pathlib file.')
-                self.assertEqual(fi.lineno(), 1)
-                self.assertEqual(fi.filelineno(), 1)
-                self.assertEqual(fi.filename(), os.fspath(t1))
-        finally:
-            remove_tempfiles(t1)
+        t1 = Path(self.writeTmp("Pathlib file."))
+        with FileInput(t1) as fi:
+            line = fi.readline()
+            self.assertEqual(line, 'Pathlib file.')
+            self.assertEqual(fi.lineno(), 1)
+            self.assertEqual(fi.filelineno(), 1)
+            self.assertEqual(fi.filename(), os.fspath(t1))
 
     def test_pathlib_file_inplace(self):
-        t1 = None
-        try:
-            t1 = Path(writeTmp(1, ['Pathlib file.']))
-            with FileInput(t1, inplace=True) as fi:
-                line = fi.readline()
-                self.assertEqual(line, 'Pathlib file.')
-                print('Modified %s' % line)
-            with open(t1) as f:
-                self.assertEqual(f.read(), 'Modified Pathlib file.\n')
-        finally:
-            remove_tempfiles(t1)
+        t1 = Path(self.writeTmp('Pathlib file.'))
+        with FileInput(t1, inplace=True) as fi:
+            line = fi.readline()
+            self.assertEqual(line, 'Pathlib file.')
+            print('Modified %s' % line)
+        with open(t1) as f:
+            self.assertEqual(f.read(), 'Modified Pathlib file.\n')
 
 
 class MockFileInput: