tests/extmod: Add tests for verifying FAT and littlefs mtime values.

Verifies mtime timestamps on files match the value returned by time.time().

Also update vfs_fat_ramdisk.py so it doesn't check FAT timestamp of the
root, because that may change across runs/ports.
Signed-off-by: Damien George <damien@micropython.org>

tests/extmod/vfs_fat_mtime.py

+# Test for VfsFat using a RAM device, mtime feature
+
+try:
+    import utime, uos
+
+    utime.time
+    utime.sleep
+    uos.VfsFat
+except (ImportError, AttributeError):
+    print("SKIP")
+    raise SystemExit
+
+
+class RAMBlockDevice:
+    ERASE_BLOCK_SIZE = 512
+
+    def __init__(self, blocks):
+        self.data = bytearray(blocks * self.ERASE_BLOCK_SIZE)
+
+    def readblocks(self, block, buf):
+        addr = block * self.ERASE_BLOCK_SIZE
+        for i in range(len(buf)):
+            buf[i] = self.data[addr + i]
+
+    def writeblocks(self, block, buf):
+        addr = block * self.ERASE_BLOCK_SIZE
+        for i in range(len(buf)):
+            self.data[addr + i] = buf[i]
+
+    def ioctl(self, op, arg):
+        if op == 4:  # block count
+            return len(self.data) // self.ERASE_BLOCK_SIZE
+        if op == 5:  # block size
+            return self.ERASE_BLOCK_SIZE
+
+
+def test(bdev, vfs_class):
+    print("test", vfs_class)
+
+    # Initial format of block device.
+    vfs_class.mkfs(bdev)
+
+    # construction
+    vfs = vfs_class(bdev)
+
+    # Create an empty file, should have a timestamp.
+    current_time = int(utime.time())
+    vfs.open("test1", "wt").close()
+
+    # Wait 2 seconds so mtime will increase (FAT has 2 second resolution).
+    utime.sleep(2)
+
+    # Create another empty file, should have a timestamp.
+    vfs.open("test2", "wt").close()
+
+    # Stat the files and check mtime is non-zero.
+    stat1 = vfs.stat("test1")
+    stat2 = vfs.stat("test2")
+    print(stat1[8] != 0, stat2[8] != 0)
+
+    # Check that test1 has mtime which matches time.time() at point of creation.
+    # TODO this currently fails on the unix port because FAT stores timestamps
+    # in localtime and stat() is UTC based.
+    # print(current_time - 1 <= stat1[8] <= current_time + 1)
+
+    # Check that test1 is older than test2.
+    print(stat1[8] < stat2[8])
+
+    # Unmount.
+    vfs.umount()
+
+
+bdev = RAMBlockDevice(50)
+test(bdev, uos.VfsFat)

tests/extmod/vfs_fat_mtime.py.exp

+test <class 'VfsFat'>
+True True
+True

tests/extmod/vfs_fat_ramdisk.py

@@ -63,7 +63,7 @@ with vfs.open("foo_file.txt", "w") as f:
     f.write("hello!")
 print(list(vfs.ilistdir()))
 
-print("stat root:", vfs.stat("/"))
+print("stat root:", vfs.stat("/")[:-3])  # timestamps differ across runs
 print("stat file:", vfs.stat("foo_file.txt")[:-3])  # timestamps differ across runs
 
 print(b"FOO_FILETXT" in bdev.data)

tests/extmod/vfs_fat_ramdisk.py.exp

@@ -4,7 +4,7 @@ statvfs: (512, 512, 16, 16, 16, 0, 0, 0, 0, 255)
 getcwd: /
 True
 [('foo_file.txt', 32768, 0, 6)]
-stat root: (16384, 0, 0, 0, 0, 0, 0, 0, 0, 0)
+stat root: (16384, 0, 0, 0, 0, 0, 0)
 stat file: (32768, 0, 0, 0, 0, 0, 6)
 True
 True

tests/extmod/vfs_lfs_mtime.py

@@ -3,6 +3,7 @@
 try:
     import utime, uos
 
+    utime.time
     utime.sleep
     uos.VfsLfs2
 except (ImportError, AttributeError):
@@ -46,6 +47,7 @@ def test(bdev, vfs_class):
     vfs = vfs_class(bdev, mtime=True)
 
     # Create an empty file, should have a timestamp.
+    current_time = int(utime.time())
     vfs.open("test1", "wt").close()
 
     # Wait 1 second so mtime will increase by at least 1.
@@ -54,10 +56,15 @@ def test(bdev, vfs_class):
     # Create another empty file, should have a timestamp.
     vfs.open("test2", "wt").close()
 
-    # Stat the files and check that test1 is older than test2.
+    # Stat the files and check mtime is non-zero.
     stat1 = vfs.stat("test1")
     stat2 = vfs.stat("test2")
     print(stat1[8] != 0, stat2[8] != 0)
+
+    # Check that test1 has mtime which matches time.time() at point of creation.
+    print(current_time <= stat1[8] <= current_time + 1)
+
+    # Check that test1 is older than test2.
     print(stat1[8] < stat2[8])
 
     # Wait 1 second so mtime will increase by at least 1.

tests/extmod/vfs_lfs_mtime.py.exp

@@ -4,6 +4,7 @@ True True
 True
 True
 True
+True
 mtime=False
 True
 True