diff --git a/tests/extmod/vfs_blockdev.py b/tests/extmod/vfs_blockdev.py
new file mode 100644
index 0000000000..d82b10610f
--- /dev/null
+++ b/tests/extmod/vfs_blockdev.py
@@ -0,0 +1,70 @@
+# Test for behaviour of combined standard and extended block device
+
+try:
+    import uos
+    uos.VfsFat
+    uos.VfsLfs2
+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, off=0):
+        addr = block * self.ERASE_BLOCK_SIZE + off
+        for i in range(len(buf)):
+            buf[i] = self.data[addr + i]
+
+    def writeblocks(self, block, buf, off=None):
+        if off is None:
+            # erase, then write
+            off = 0
+        addr = block * self.ERASE_BLOCK_SIZE + off
+        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
+        if op == 6: # erase block
+            return 0
+
+def test(bdev, vfs_class):
+    print('test', vfs_class)
+
+    # mkfs
+    vfs_class.mkfs(bdev)
+
+    # construction
+    vfs = vfs_class(bdev)
+
+    # statvfs
+    print(vfs.statvfs('/'))
+
+    # open, write close
+    f = vfs.open('test', 'w')
+    for i in range(10):
+        f.write('some data')
+    f.close()
+
+    # ilistdir
+    print(list(vfs.ilistdir()))
+
+    # read
+    with vfs.open('test', 'r') as f:
+        print(f.read())
+
+try:
+    bdev = RAMBlockDevice(50)
+except MemoryError:
+    print("SKIP")
+    raise SystemExit
+
+test(bdev, uos.VfsFat)
+test(bdev, uos.VfsLfs2)
diff --git a/tests/extmod/vfs_blockdev.py.exp b/tests/extmod/vfs_blockdev.py.exp
new file mode 100644
index 0000000000..a254133131
--- /dev/null
+++ b/tests/extmod/vfs_blockdev.py.exp
@@ -0,0 +1,8 @@
+test <class 'VfsFat'>
+(512, 512, 16, 16, 16, 0, 0, 0, 0, 255)
+[('test', 32768, 0, 90)]
+some datasome datasome datasome datasome datasome datasome datasome datasome datasome data
+test <class 'VfsLfs2'>
+(512, 512, 50, 48, 48, 0, 0, 0, 0, 255)
+[('test', 32768, 0, 90)]
+some datasome datasome datasome datasome datasome datasome datasome datasome datasome data