d14d07a079
Commitce00d61917("db: implement large_data virtual tables with feature flag gating") changed these two tests to construct their mutation with a randomly generated partition key (simple_schema::make_pkey()) instead of the previously fixed pk "pv", with the comment that this avoids a "Failed to generate sharding metadata" error. simple_schema::make_pkey() delegates to tests::generate_partition_key(), which defaults to key_size{1, 128}, i.e. the partition key length is uniformly random in [1, 128] bytes. That interacts badly with the fact that both tests pick thresholds at exact byte boundaries of the MC sstable row encoding: - The large-data handler records a row's size as _data_writer->offset() - current_pos (sstables/mx/writer.cc: collect_row_stats()), i.e. the number of bytes the row took on disk. - For the first clustering row, the body includes a vint-encoded prev_row_size = pos - _prev_row_start. - _prev_row_start is captured at the start of the partition (consume_new_partition()) before the partition key is written to the data stream, so prev_row_size rolls in the partition key's serialized length (2-byte prefix + pk bytes) + deletion_time + static row size. A random-size partition key therefore perturbs the first clustering row's encoded size by 1-2 bytes across runs (the vint of prev_row_size crosses the 128 boundary), flipping the test's byte-exact threshold comparison. On seed 2104744000 this produced: critical check row_size_count == expected.size() has failed [3 != 2] Fix the two byte-exact-sensitive tests by reverting their partition key to the fixed s.new_mutation("pv") used beforece00d61917. Under smp=1 (which these tests run with, per -c1 in the test invocation) a fixed key is always shard-local, so no sharding-metadata issue arises here. The other tests modified byce00d61917(test_sstable_log_too_many_rows, test_sstable_log_too_many_dead_rows, test_sstable_too_many_collection_elements, test_large_data_records_round_trip, etc.) assert on row/element counts or use thresholds with enough slack that the partition key size does not matter, and are left unchanged. Add an explanatory comment to each fixed site so the pitfall is not re-introduced by a future refactor. Verified stable with: ./test.py --mode=dev test/boost/sstable_3_x_test.cc::test_sstable_write_large_row --repeat 100 --max-failures 1 ./test.py --mode=dev test/boost/sstable_3_x_test.cc::test_sstable_write_large_cell --repeat 100 --max-failures 1 ./test.py --mode=release test/boost/sstable_3_x_test.cc::test_sstable_write_large_row --repeat 100 --max-failures 1 ./test.py --mode=release test/boost/sstable_3_x_test.cc::test_sstable_write_large_cell --repeat 100 --max-failures 1 All four invocations: 100/100 passed. Fixes: SCYLLADB-1685 Closes scylladb/scylladb#29621
Scylla unit tests using C++ and the Boost test framework
The source files in this directory are Scylla unit tests written in C++ using the Boost.Test framework. These unit tests come in three flavors:
-
Some simple tests that check stand-alone C++ functions or classes use Boost's
BOOST_AUTO_TEST_CASE. -
Some tests require Seastar features, and need to be declared with Seastar's extensions to Boost.Test, namely
SEASTAR_TEST_CASE. -
Even more elaborate tests require not just a functioning Seastar environment but also a complete (or partial) Scylla environment. Those tests use the
do_with_cql_env()ordo_with_cql_env_thread()function to set up a mostly-functioning environment behaving like a single-node Scylla, in which the test can run.
While we have many tests of the third flavor, writing new tests of this type should be reserved to white box tests - tests where it is necessary to inspect or control Scylla internals that do not have user-facing APIs such as CQL. In contrast, black-box tests - tests that can be written only using user-facing APIs, should be written in one of newer test frameworks that we offer - such as test/cqlpy or test/alternator (in Python, using the CQL or DynamoDB APIs respectively) or test/cql (using textual CQL commands), or - if more than one Scylla node is needed for a test - using the test/topology* framework.
Running tests
Because these are C++ tests, they need to be compiled before running.
To compile a single test executable row_cache_test, use a command like
ninja build/dev/test/boost/row_cache_test
You can also use ninja dev-test to build all C++ tests, or use
ninja deb-build to build the C++ tests and also the full Scylla executable
(however, note that full Scylla executable isn't needed to run Boost tests).
Replace "dev" by "debug" or "release" in the examples above and below to use the "debug" build mode (which, importantly, compiles the test with ASAN and UBSAN enabling on and helps catch difficult-to-catch use-after-free bugs) or the "release" build mode (optimized for run speed).
To run an entire test file row_cache_test, including all its test
functions, use a command like:
build/dev/test/boost/row_cache_test -- -c1 -m1G
to run a single test function test_reproduce_18045() from the longer test
file, use a command like:
build/dev/test/boost/row_cache_test -t test_reproduce_18045 -- -c1 -m1G
In these command lines, the parameters before the -- are passed to
Boost.Test, while the parameters after the -- are passed to the test code,
and in particular to Seastar. In this example Seastar is asked to run on one
CPU (-c1) and use 1G of memory (-m1G) instead of hogging the entire
machine. The Boost.Test option -t test_reproduce_18045 asks it to run just
this one test function instead of all the test functions in the executable.
Unfortunately, interrupting a running test with control-C while doesn't
work. This is a known bug (#5696). Kill a test with SIGKILL (-9) if you
need to kill it while it's running.
Boost tests can also be run using test.py - which is a script that provides a uniform way to run all tests in scylladb.git - C++ tests, Python tests, etc.
Execution with pytest
To run all tests with pytest execute
pytest test/boost
To execute all tests in one file, provide the path to the source filename as a parameter
pytest test/boost/aggregate_fcts_test.cc
Since it's a normal path, autocompletion works in the terminal out of the box.
To execute only one test function, provide the path to the source file and function name
pytest --mode dev test/boost/aggregate_fcts_test.cc::test_aggregate_avg
To provide a specific mode, use the next parameter --mode dev,
if parameter isn't provided pytest tries to use ninja mode_list to find out the compiled modes.
Parallel execution is controlled by pytest-xdist and the parameter -n auto.
This command starts tests with the number of workers equal to CPU cores.
The useful command to discover the tests in the file or directory is
pytest --collect-only -q --mode dev test/boost/aggregate_fcts_test.cc
That will return all test functions in the file.
To execute only one function from the test, you can invoke the output from the previous command.
However, suffix for mode should be skipped.
For example,
output shows in the terminal something like this test/boost/aggregate_fcts_test.cc::test_aggregate_avg.dev.
So to execute this specific test function, please use the next command
pytest --mode dev test/boost/aggregate_fcts_test.cc::test_aggregate_avg
Writing tests
Because of the large build time and build size of each separate test executable, it is recommended to put test functions into relatively large source files. But not too large - to keep compilation time of a single source file (during development) at reasonable levels.
When adding new source files in test/boost, don't forget to list the new source file in configure.py and also in CMakeLists.txt. The former is needed by our CI, but the latter is preferred by some developers.