opt: standardize mock usage for unit testing C functions

[ivila]

There are several changes in this PR:

1. Add a mock feature to optee-utee-sys, following the mockall FFI example.
2. Use the optee-utee-sys mock feature for unit testing in optee-utee.
3. Remove the optee-utee-mock crate.
4. Some minor changes, including fixing compiler warnings and formatting files.

closes #218

[DemesneGH]

@ivila Sorry for missing your message, a bit busy these days...

The PR looks good for me, and the reorganization of mock features makes a lot of sense. Thanks for the effort!

I've tested it locally with optee-utee's object tests:

$ cargo test --package optee-utee --lib -- object::persistent_object::tests --nocapture
...
running 4 tests
test object::persistent_object::tests::test_create_and_drop ... ok
test object::persistent_object::tests::test_create_and_failed_close_delete ... ok
test object::persistent_object::tests::test_create_and_successfully_close_delete ... ok
test object::persistent_object::tests::test_create_failed ... ok

test result: ok. 4 passed; 0 failed; 0 ignored; 0 measured; 10 filtered out; finished in 0.00s

Two more considerations:

• Could you please add a simple doc in docs/ regarding the mock's background and usage, like "OP-TEE Modules Unit Testing with Mocks"? Having a reference would be very helpful for other contributors who are willing to develop the optee modules.
• Consider adding this unit test into our CI jobs?

[ivila]

@ivila Sorry for missing your message, a bit busy these days...

The PR looks good for me, and the reorganization of mock features makes a lot of sense. Thanks for the effort!

I've tested it locally with optee-utee's object tests:

$ cargo test --package optee-utee --lib -- object::persistent_object::tests --nocapture
...
running 4 tests
test object::persistent_object::tests::test_create_and_drop ... ok
test object::persistent_object::tests::test_create_and_failed_close_delete ... ok
test object::persistent_object::tests::test_create_and_successfully_close_delete ... ok
test object::persistent_object::tests::test_create_failed ... ok

test result: ok. 4 passed; 0 failed; 0 ignored; 0 measured; 10 filtered out; finished in 0.00s

Two more considerations:

• Could you please add a simple doc in docs/ regarding the mock's background and usage, like "OP-TEE Modules Unit Testing with Mocks"? Having a reference would be very helpful for other contributors who are willing to develop the optee modules.
• Consider adding this unit test into our CI jobs?

Could you please add a simple doc

Yes, will do

Consider adding this unit test into our CI jobs

Sorry for my previous response, we have already added this into the CI jobs:

teaclave-trustzone-sdk/.github/workflows/reuse_test.yml

Line 54 in fac9759

(cd optee-utee && cargo test --features no_panic_handler -vv)

[DemesneGH]

Sorry for my previous response, we have already added this into the CI jobs:

Ah I see, thanks!