3 files changed, 81 insertions, 0 deletions
diff --git a/tests/extmod/vfs_userfs.py b/tests/extmod/vfs_userfs.py
new file mode 100644
index 000000000..e913f9748
--- /dev/null
+++ b/tests/extmod/vfs_userfs.py
@@ -0,0 +1,68 @@
+# test VFS functionality with a user-defined filesystem
+# also tests parts of uio.IOBase implementation
+
+import sys, uio
+
+try:
+    uio.IOBase
+    import uos
+    uos.mount
+except (ImportError, AttributeError):
+    print("SKIP")
+    raise SystemExit
+
+
+class UserFile(uio.IOBase):
+    def __init__(self, data):
+        self.data = data
+        self.pos = 0
+    def read(self):
+        return self.data
+    def readinto(self, buf):
+        n = 0
+        while n < len(buf) and self.pos < len(self.data):
+            buf[n] = self.data[self.pos]
+            n += 1
+            self.pos += 1
+        return n
+    def ioctl(self, req, arg):
+        print('ioctl', req, arg)
+        return 0
+
+
+class UserFS:
+    def __init__(self, files):
+        self.files = files
+    def mount(self, readonly, mksfs):
+        pass
+    def umount(self):
+        pass
+    def stat(self, path):
+        print('stat', path)
+        if path in self.files:
+            return (32768, 0, 0, 0, 0, 0, 0, 0, 0, 0)
+        raise OSError
+    def open(self, path, mode):
+        print('open', path, mode)
+        return UserFile(self.files[path])
+
+
+# create and mount a user filesystem
+user_files = {
+    '/data.txt': b"some data in a text file\n",
+    '/usermod1.py': b"print('in usermod1')\nimport usermod2",
+    '/usermod2.py': b"print('in usermod2')",
+}
+uos.mount(UserFS(user_files), '/userfs')
+
+# open and read a file
+f = open('/userfs/data.txt')
+print(f.read())
+
+# import files from the user filesystem
+sys.path.append('/userfs')
+import usermod1
+
+# unmount and undo path addition
+uos.umount('/userfs')
+sys.path.pop()
diff --git a/tests/extmod/vfs_userfs.py.exp b/tests/extmod/vfs_userfs.py.exp
new file mode 100644
index 000000000..6a4d925b9
--- /dev/null
+++ b/tests/extmod/vfs_userfs.py.exp
@@ -0,0 +1,12 @@
+open /data.txt r
+b'some data in a text file\n'
+stat /usermod1
+stat /usermod1.py
+open /usermod1.py r
+ioctl 4 0
+in usermod1
+stat /usermod2
+stat /usermod2.py
+open /usermod2.py r
+ioctl 4 0
+in usermod2
diff --git a/tests/run-tests b/tests/run-tests
index 25fb33a3f..cfd7c4037 100755
--- a/tests/run-tests
+++ b/tests/run-tests
@@ -364,6 +364,7 @@ def run_tests(pyb, tests, args, base_path="."):
         skip_tests.add('micropython/schedule.py') # native code doesn't check pending events
         skip_tests.add('stress/gc_trace.py') # requires yield
         skip_tests.add('stress/recursive_gen.py') # requires yield
+        skip_tests.add('extmod/vfs_userfs.py') # because native doesn't properly handle globals across different modules
 
     for test_file in tests:
         test_file = test_file.replace('\\', '/')