Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=131072
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=131072 backing_file=TEST_DIR/t.IMGFMT.base
-qemu-io: can't open device TEST_DIR/t.IMGFMT: Could not open backing file: Could not open 'TEST_DIR/t.IMGFMT.base': No such file or directory
+can't open device TEST_DIR/t.IMGFMT: Could not open backing file: Could not open 'TEST_DIR/t.IMGFMT.base': No such file or directory
*** done