libntruprime: Test

To run the full test suite after compiling and installing libntruprime, run `ntruprime-fulltest`. This indicates success in two ways: it prints `full tests succeeded` as its last line of output; it exits 0.

Any change in the compiled library (compiling for a different architecture, compiling with a different compiler, etc.) must be subjected to a new round of tests. A compiled version of libntruprime that does not pass the full test suite is not supported.

One run of `ntruprime-fulltest` was observed to take 529 core-minutes on a 2.245GHz EPYC 7742 with overclocking disabled. This test finished in 35 minutes of real time; `ntruprime-fulltest` includes some automatic parallelization. To limit the number of threads used to 1, run `env THREADS=1 ntruprime-fulltest`.

libntruprime automatically selects AVX2 implementations when it is running on an Intel/AMD CPU that supports AVX2, while falling back to portable implementations otherwise. Running `ntruprime-fulltest` on an Intel/AMD CPU without AVX2 will say `CPU does not support implementation` for the AVX2 implementations and will fail. To test a compilation of libntruprime for Intel/AMD CPUs, you have to pick an Intel/AMD CPU with AVX2 to run `ntruprime-fulltest`.

The rest of this page says more about what is happening inside `ntruprime-fulltest`.

### Conventional tests

The workhorse inside `ntruprime-fulltest` is a separate `ntruprime-test` program.

Simply calling `ntruprime-test` without arguments will run SUPERCOP-style tests that the subroutines in libntruprime produce the expected results for known inputs (including known randomness), and will indicate success in two ways: printing `all tests succeeded` as the last line of output, and exiting 0.

For parallelism, `ntruprime-fulltest` calls `ntruprime-test` many times, using optional `ntruprime-test` arguments to narrow which subroutines are being tested.

### Data-flow tests

Another way that `ntruprime-fulltest` runs `ntruprime-test` is as follows, running TIMECOP-style tests that branch conditions and array indices are independent of secrets:

    env valgrind_multiplier=1 \
    valgrind -q \
    --error-exitcode=99 \
    ntruprime-test

This requires `valgrind` to be installed at test time. The output will include a line `valgrind 1 declassify 1` if the library was compiled with `--valgrind` (which is the only supported option), or a line `valgrind 1 declassify 0 (expect false positives)` otherwise.

These data-flow tests do not supersede the conventional tests. The conventional tests run code directly on the CPU and might catch issues hidden by the emulation in `valgrind`. The conventional tests also include some memory tests that are disabled to improve the `valgrind` memory tests but that are not necessarily superseded by the `valgrind` memory tests.

Version: This is version 2024.08.15 of the "Test" web page.