tests/extmod/vfs_fat_fsusermount: Improve fsusermount test coverage.

tests/extmod/vfs_fat_fsusermount.py

+import sys
+import uos
+import uerrno
+try:
+    uos.VfsFat
+except AttributeError:
+    print("SKIP")
+    sys.exit()
+
+
+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]
+
+    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]
+
+    def ioctl(self, op, arg):
+        #print("ioctl(%d, %r)" % (op, arg))
+        if op == 4:  # BP_IOCTL_SEC_COUNT
+            return len(self.data) // self.SEC_SIZE
+        if op == 5:  # BP_IOCTL_SEC_SIZE
+            return self.SEC_SIZE
+
+
+try:
+    bdev = RAMFS(48)
+except MemoryError:
+    print("SKIP")
+    sys.exit()
+
+# can't mkfs readonly device
+try:
+    uos.vfs_mkfs(bdev, "/ramdisk", readonly=True)
+except OSError as e:
+    print(e)
+
+# mount before mkfs
+try:
+    uos.vfs_mount(bdev, "/ramdisk")
+except OSError as e:
+    print(e)
+
+# invalid umount
+try:
+    uos.vfs_umount("/ramdisk")
+except OSError as e:
+    print(e.args[0] == uerrno.EINVAL)
+
+try:
+    uos.vfs_mount(None, "/ramdisk")
+except OSError as e:
+    print(e)
+
+try:
+    uos.vfs_mkfs(None, "/ramdisk")
+except OSError as e:
+    print(e)
+
+# valid mkfs/mount
+uos.vfs_mkfs(bdev, "/ramdisk")
+uos.vfs_mount(bdev, "/ramdisk")
+
+# umount by path
+uos.vfs_umount("/ramdisk")
+
+# readonly mount
+uos.vfs_mount(bdev, "/ramdisk", readonly=True)
+vfs = uos.VfsFat(bdev, "/ramdisk")
+try:
+    f = vfs.open("file.txt", "w")
+except OSError as e:
+    print("EROFS:", e.args[0] == 30) # uerrno.EROFS
+
+# device is None == umount
+uos.vfs_mount(None, "/ramdisk")
+
+# max mounted devices
+dev = []
+try:
+    for i in range(0,4):
+        dev.append(RAMFS(48))
+        uos.vfs_mkfs(dev[i], "/ramdisk" + str(i))
+        uos.vfs_mount(dev[i], "/ramdisk" + str(i))
+except OSError as e:
+    print(e)

tests/extmod/vfs_fat_fsusermount.py.exp

+can't mkfs
+can't mount
+True
+can't umount
+can't umount
+EROFS: True
+too many devices mounted