Description
Description
Goal
As a developer and maintainer of Mbed TLS/Crypto unit tests,
I want to write auxiliary functions in separate source files which are compiled separately
so as to avoid code duplication, keep file size manageable, and organize the code in a comprehensible way, without increasing compilation time.
At least helpers.function should become one such separate file, and probably host_test.function and target_test.function. These should be ordinary .c files since the test script generator doesn't modify them.
Rationale
In the test suites, we can't easily write auxiliary functions that are used by more than one .function file, or that may or may not be used depending on compile-time options.
To define an auxiliary function that is used by more than one .function file, we have two ways:
- Define it in
helpers.functionormain_test.function, which are hard-coded in the calls togenerate_test_code.py. - Define it in a header file.
This has come up time and again, and is getting worse as we improve our test coverage and thus want more auxiliary functions for fault injection, cleanup, consistency checks, etc. For example, I started to add consistency checks for the PSA crypto API, and I had to define them in a specific header file tests/psa_crypto_helpers.h. #162 adds generic support for skipping tests when a feature is not supported by an alternative implementation, and adds a lot of boilerplate which could benefit from auxiliary functions. We should be able to define functions in other files, and let the linker link whatever is used.
Difficulties
We should change the build scripts for tests to compile .c files separately, and then link them together, instead of compiling and linking a single .c file at once.
The main difficulty is to update mbedtls_test.py and the procedure to use it. This makes #249 a de facto prerequisite.
Issue request type
[ ] Question
[x] Enhancement
[ ] Bug