Am 21.07.2017 um 11:34 hat Stefan Hajnoczi geschrieben: > There is not much getting started documentation for qemu-iotests. This > patch explains how to create a new test and covers the overall testing > approach. > > Cc: Ishani Chugh <chugh.ish...@research.iiit.ac.in> > Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com> > --- > tests/qemu-iotests/README | 83 > +++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 83 insertions(+) > > diff --git a/tests/qemu-iotests/README b/tests/qemu-iotests/README > index 6079b40..8259b9f 100644 > --- a/tests/qemu-iotests/README > +++ b/tests/qemu-iotests/README > @@ -14,8 +14,91 @@ Just run ./check to run all tests for the raw image > format, or ./check > -qcow2 to test the qcow2 image format. The output of ./check -h explains > additional options to test further image formats or I/O methods. > > +* Testing approach > + > +Each test is an executable file (usually a bash script) that is run by the > +./check test harness. Standard out and standard error are captured to an > +output file. If the output file differs from the "golden master" output file > +for the test then it fails. > + > +Tests are simply a sequence of commands that produce output and the test > itself > +does not judge whether it passed or failed. If you find yourself writing > +checks to determine success or failure then you should rethink the test and > +rely on output diffing instead. > + > +** Filtering volatile output > + > +When output contains absolute file paths, timestamps, process IDs, hostnames, > +or other volatile strings, the diff against golden master output will fail. > +Such output must be filtered to replace volatile strings with fixed > +placeholders. > + > +For example, the path to the temporary working directory changes between test > +runs so it must be filtered: > + > + sed -e "s#$TEST_DIR/#TEST_DIR/#g" > + > +Commonly needed filters are available in ./common.filter. > + > +** Python tests > + > +Most tests are implemented in bash but it is difficult to interact with the > QMP > +monitor. A Python module called 'iotests' is available for tests that > require > +JSON and interacting with QEMU. > + > +* How to create a test > + > +1. Choose an unused test number > + > +Tests are identified by a unique number. Look for the highest test case > number > +by looking at the test files. Then search the qemu-devel@nongnu.org mailing > +list to check if anyone has already sent patches using the next available > +number. You may need to increment the number a few times to reach an unused > +number. > + > +2. Create the test file > + > +Copy an existing test (one that most closely resembles what you wish to test) > +to the new test number: > + > + cp 001 <test-number> > + > +3. Assign groups to the test > + > +Add your test to the ./group file. This file is the index of tests and > assigns > +them to functional groups like "rw" for read-write tests. Most tests belong > to > +the "rw" and "auto" groups. "auto" means the test runs when ./check is > invoked > +without a -g argument. > + > +Consider adding your test to the "quick" group if it executes quickly (<1s). > +This group is run by "make check-block" and is often included as part of > build > +tests in continuous integration systems. > + > +4. Write the test > + > +Edit the test script. Look at existing tests for examples. > + > +5. Generate the golden master file > + > +Run your test with "./check <test-number>". You may need to pass additional > +options to use an image format or protocol.
./check refuses to even run a test if the reference output is missing. So in practice you need a 'touch <test-number>.out' first. > +The test will fail because there is no golden master yet. Inspect the output > +that your test generated with "cat <test-number>.out.bad". > + > +Verify that the output is as expected and contains no volatile strings like > +timestamps. You may need to add filters to your test to remove volatile > +strings. > + > +Once you are happy with the test output it can be used as the golden master > +with "mv <test-number>.out.bad <test-number>.out". Rerun the test to verify > +that it passes. > + > +Congratulations, you've created a new test! Looks good otherwise. Kevin
