Re: [Libguestfs] [nbdkit PATCH v2] tests: Check that cache-min-block-size works properly

Signed-off-by: Martin Kletzander <mkletzan(a)redhat.com&gt; --- tests/test-cache-block-size.sh | 41 +++++++++++++++++++++------------- 1 file changed, 26 insertions(+), 15 deletions(-) diff --git a/tests/test-cache-block-size.sh b/tests/test-cache-block-size.sh index d20cc94002b6..403c295e57c9 100755 --- a/tests/test-cache-block-size.sh +++ b/tests/test-cache-block-size.sh @@ -43,28 +43,39 @@ rm -f $files cleanup_fn rm -f $files # Create an empty base image. -truncate -s 128K cache-block-size.img +truncate -s 256K cache-block-size.img # Run nbdkit with the caching filter. start_nbdkit -P cache-block-size.pid -U $sock --filter=cache \ - file cache-block-size.img cache-min-block-size=4K + file cache-block-size.img cache-min-block-size=128K \ + cache-on-read=true nbdsh --connect "nbd+unix://?socket=$sock" \ -c ' -# Write some pattern data to the overlay and check it reads back OK. -buf = b"abcd" * 16384 -h.pwrite(buf, 32768) -zero = h.pread(32768, 0) -assert zero == bytearray(32768) -buf2 = h.pread(65536, 32768) -assert buf == buf2 +# Read half of cache-min-block-size + +zero = h.pread(64 * 1024, 0) +assert zero == bytearray(64 * 1024) + +buf = b"abcd" * 16 * 1024 -# Flushing should write through to the underlying file. -h.flush() +# Write past the first read +with open("cache-block-size.img", "wb") as file: + file.seek(64 * 1024) + file.write(buf * 2) + file.truncate(256 * 1024) +# Check that it got written with open("cache-block-size.img", "rb") as file: - zero = file.read(32768) - assert zero == bytearray(32768) - buf2 = file.read(65536) - assert buf == buf2 + file.seek(64 * 1024) + buf2 = file.read(128 * 1024) + assert (buf * 2) == buf2 + +# Now read the rest of the cache-min-block-size, it should stay empty +zero = h.pread(64 * 1024, 64 * 1024) +assert zero == bytearray(64 * 1024) + +# Read past that, the pattern should be visible there +buf2 = h.pread(64 * 1024, 128 * 1024) +assert buf == buf2 '