|  | QA output created by 114 | 
|  | Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.orig backing_fmt=raw | 
|  | Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=67108864 | 
|  | qemu-img: Use of backing file requires explicit backing format | 
|  | Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT | 
|  | Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT | 
|  | image: TEST_DIR/t.IMGFMT | 
|  | file format: IMGFMT | 
|  | virtual size: 64 MiB (67108864 bytes) | 
|  | cluster_size: 65536 | 
|  | backing file: TEST_DIR/t.IMGFMT.base | 
|  | backing file format: foo | 
|  | qemu-io: can't open device TEST_DIR/t.qcow2: Could not open backing file: Unknown driver 'foo' | 
|  | no file open, try 'help open' | 
|  | read 4096/4096 bytes at offset 0 | 
|  | 4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) | 
|  | qemu-img: Could not change the backing file to 'TEST_DIR/t.qcow2.base': backing format must be specified | 
|  | read 4096/4096 bytes at offset 0 | 
|  | 4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) | 
|  | *** done |