Adapted file timestamp update to real fs behavior

- tests originally by @simonfagerholm, adapted
- fixes #435

CHANGES.md

@@ -19,6 +19,8 @@ keep using pyfakefs 3.4.3, or upgrade to a newer Python version.
 #### Infrastructure
 
 #### Fixes
+  * file timestamps are now updated more according to the real behavior
+    ([#435](../../issues/435))
 
 ## [Version 3.4.3](https://pypi.python.org/pypi/pyfakefs/3.4.3)
 

pyfakefs/fake_filesystem.py

@@ -341,12 +341,17 @@ def _set_initial_contents(self, contents):
            Called internally after initial file creation.
 
         Args:
-          contents: string, new content of file.
+            contents: string, new content of file.
+
+        Returns:
+            True if the contents have been changed.
+
         Raises:
-          IOError: if the st_size is not a non-negative integer,
+              IOError: if the st_size is not a non-negative integer,
                    or if st_size exceeds the available file system space
         """
         contents = self._encode_contents(contents)
+        changed = self._byte_contents != contents
         st_size = len(contents)
 
         if self._byte_contents:
@@ -357,6 +362,7 @@ def _set_initial_contents(self, contents):
         self._byte_contents = contents
         self.st_size = st_size
         self.epoch += 1
+        return changed
 
     def set_contents(self, contents, encoding=None):
         """Sets the file contents and size and increases the modification time.
@@ -373,12 +379,10 @@ def set_contents(self, contents, encoding=None):
                    or if it exceeds the available file system space.
         """
         self.encoding = encoding
-        self._set_initial_contents(contents)
-        current_time = time.time()
-        self.st_ctime = current_time
-        self.st_mtime = current_time
+        changed = self._set_initial_contents(contents)
         if self._side_effect is not None:
             self._side_effect(self)
+        return changed
 
     @property
     def size(self):
@@ -4450,6 +4454,7 @@ def __init__(self, file_object, file_path, update=False, read=False,
         self.raw_io = raw_io
         self._binary = binary
         self.is_stream = is_stream
+        self._changed = False
         contents = file_object.byte_contents
         self._encoding = encoding or locale.getpreferredencoding(False)
         errors = errors or 'strict'
@@ -4514,6 +4519,8 @@ def close(self):
         # for raw io, all writes are flushed immediately
         if self.allow_update and not self.raw_io:
             self.flush()
+            if self._filesystem.is_windows_fs and self._changed:
+                self.file_object.st_mtime = time.time()
         if self._closefd:
             self._filesystem._close_open_file(self.filedes)
         else:
@@ -4541,7 +4548,13 @@ def flush(self):
                 self.update_flush_pos()
             else:
                 self._io.flush()
-            self.file_object.set_contents(contents, self._encoding)
+            if self.file_object.set_contents(contents, self._encoding):
+                if self._filesystem.is_windows_fs:
+                    self._changed = True
+                else:
+                    current_time = time.time()
+                    self.file_object.st_ctime = current_time
+                    self.file_object.st_mtime = current_time
             self._file_epoch = self.file_object.epoch
 
             if not self.is_stream:
@@ -4772,6 +4785,8 @@ def __getattr__(self, name):
             self._sync_io()
             if self._flushes_after_read():
                 self.flush()
+            if not self._filesystem.is_windows_fs:
+                self.file_object.st_atime = time.time()
         if truncate:
             return self._truncate_wrapper()
         if self._append:
@@ -4992,6 +5007,12 @@ def call(self, file_, mode='r', buffering=-1, encoding=None,
         # If you print obj.name, the argument to open() must be printed.
         # Not the abspath, not the filename, but the actual argument.
         file_object.opened_as = file_path
+        if open_modes.truncate:
+            current_time = time.time()
+            file_object.st_mtime = current_time
+            if not self.filesystem.is_windows_fs:
+                file_object.st_ctime = current_time
+
 
         fakefile = FakeFileWrapper(file_object,
                                    file_path,

pyfakefs/tests/all_tests.py

@@ -20,7 +20,7 @@
 import unittest
 
 from pyfakefs.extra_packages import pathlib
-from pyfakefs.tests import dynamic_patch_test
+from pyfakefs.tests import dynamic_patch_test, fake_stat_time_test
 from pyfakefs.tests import fake_open_test
 from pyfakefs.tests import fake_os_test
 from pyfakefs.tests import example_test
@@ -46,6 +46,7 @@ def suite(self):  # pylint: disable-msg=C6409
             loader.loadTestsFromModule(fake_filesystem_glob_test),
             loader.loadTestsFromModule(fake_filesystem_shutil_test),
             loader.loadTestsFromModule(fake_os_test),
+            loader.loadTestsFromModule(fake_stat_time_test),
             loader.loadTestsFromModule(fake_open_test),
             loader.loadTestsFromModule(fake_tempfile_test),
             loader.loadTestsFromModule(fake_filesystem_vs_real_test),

pyfakefs/tests/fake_open_test.py

@@ -424,61 +424,6 @@ def test_read_with_rplus(self):
             fake_file.seek(0)
             self.assertEqual('new contents here', fake_file.read())
 
-    def test_open_st_ctime(self):
-        # set up
-        self.skip_real_fs()
-        time.time = DummyTime(100, 10)
-        file_path = self.make_path('some_file')
-        self.assertFalse(self.os.path.exists(file_path))
-        # tests
-        fake_file = self.open(file_path, 'w')
-        time.time.start()
-        st = self.os.stat(file_path)
-        self.assertEqual(100, st.st_ctime)
-        self.assertEqual(100, st.st_mtime)
-        fake_file.close()
-        st = self.os.stat(file_path)
-        self.assertEqual(110, st.st_ctime)
-        self.assertEqual(110, st.st_mtime)
-
-        fake_file = self.open(file_path, 'w')
-        st = self.os.stat(file_path)
-        # truncating the file cause an additional stat update
-        self.assertEqual(120, st.st_ctime)
-        self.assertEqual(120, st.st_mtime)
-        fake_file.close()
-        st = self.os.stat(file_path)
-        self.assertEqual(130, st.st_ctime)
-        self.assertEqual(130, st.st_mtime)
-
-        fake_file = self.open(file_path, 'w+')
-        st = self.os.stat(file_path)
-        self.assertEqual(140, st.st_ctime)
-        self.assertEqual(140, st.st_mtime)
-        fake_file.close()
-        st = self.os.stat(file_path)
-        self.assertEqual(150, st.st_ctime)
-        self.assertEqual(150, st.st_mtime)
-
-        fake_file = self.open(file_path, 'a')
-        st = self.os.stat(file_path)
-        # not updating m_time or c_time here, since no truncating.
-        self.assertEqual(150, st.st_ctime)
-        self.assertEqual(150, st.st_mtime)
-        fake_file.close()
-        st = self.os.stat(file_path)
-        self.assertEqual(160, st.st_ctime)
-        self.assertEqual(160, st.st_mtime)
-
-        fake_file = self.open(file_path, 'r')
-        st = self.os.stat(file_path)
-        self.assertEqual(160, st.st_ctime)
-        self.assertEqual(160, st.st_mtime)
-        fake_file.close()
-        st = self.os.stat(file_path)
-        self.assertEqual(160, st.st_ctime)
-        self.assertEqual(160, st.st_mtime)
-
     def create_with_permission(self, file_path, perm_bits):
         self.create_file(file_path)
         self.os.chmod(file_path, perm_bits)