Add simple test

tests/extmod/vfs_fat_case.py

@@ -0,0 +1,70 @@
+try:
+    import uerrno
+    import uos
+except ImportError:
+    print("missing u")
+    print("SKIP")
+    raise SystemExit
+
+try:
+    uos.VfsFat
+except AttributeError:
+    print("missing VfsFat")
+    print("SKIP")
+    raise SystemExit
+
+
+class RAMFS:
+    SEC_SIZE = 512
+
+    def __init__(self, blocks):
+        self.data = bytearray(blocks * self.SEC_SIZE)
+
+    def readblocks(self, n, buf):
+        # print("readblocks(%s, %x(%d))" % (n, id(buf), len(buf)))
+        for i in range(len(buf)):
+            buf[i] = self.data[n * self.SEC_SIZE + i]
+        return 0
+
+    def writeblocks(self, n, buf):
+        # print("writeblocks(%s, %x)" % (n, id(buf)))
+        for i in range(len(buf)):
+            self.data[n * self.SEC_SIZE + i] = buf[i]
+        return 0
+
+    def ioctl(self, op, arg):
+        # print("ioctl(%d, %r)" % (op, arg))
+        if op == 4:  # MP_BLOCKDEV_IOCTL_BLOCK_COUNT
+            return len(self.data) // self.SEC_SIZE
+        if op == 5:  # MP_BLOCKDEV_IOCTL_BLOCK_SIZE
+            return self.SEC_SIZE
+
+
+try:
+    bdev = RAMFS(50)
+except MemoryError:
+    print("SKIP")
+    raise SystemExit
+
+uos.VfsFat.mkfs(bdev)
+vfs = uos.VfsFat(bdev)
+uos.mount(vfs, "/ramdisk")
+uos.chdir("/ramdisk")
+
+# Check ASCII case-insensitivity
+vfs.mkdir("foo_dir_az")
+print(uos.listdir(""))
+vfs.rmdir("fOO_dir_AZ")
+
+# Characters outside of a-z are case sensitive.
+vfs.mkdir("extended_æ")
+print(uos.listdir(""))
+try:
+    vfs.rmdir("extended_Æ")
+except OSError as e:
+    print(e.errno == uerrno.ENOENT)
+vfs.rmdir("extended_æ")
+
+# Emoji test for fun.
+vfs.mkdir("emoji_😀")
+vfs.rmdir("emoji_😀")

tests/extmod/vfs_fat_case.py.exp

@@ -0,0 +1,3 @@
+['foo_dir_az']
+['extended_æ']
+True