build: Create test utility library from src/test/util/

[maflcko]

The purpose of the good first issue label is to highlight which issues are suitable for a new contributor without a deep understanding of the codebase.

Useful skills

• Experience with autotools build systems

Task

The test utility library in https://github.com/bitcoin/bitcoin/tree/master/src/test/util is currently only a folder and each module in there is compiled for each target that uses it. For example, setup_common is compiled 27 times (for the fuzz suite) and another 3 times for the other tests (bench, unit test, gui). To speed up the compilation and clarify build dependencies, this folder should be transformed into an actual library.

Because our test binaries should test as much as possible, this library may depend on any Bitcoin Core library or third party library (except boost-unit-test). It should be built when at least one target that requires it is built, skipped otherwise.

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[brakmic]

Hi,

I've started working on this. Not sure if I understood the goals correctly (and if I should write anything here), but I can at least generate a static lib based on src/test/util sources. I've also removed the many src/util/test headers from Makefile.test.include, because I don't need them anymore to compile individual tests.
Instead, I've put into each test's LDADD the libtest_util.a, that is $(LIBTEST_UTIL). However, I'm not quite sure if this is the correct way to do it.

There's also a new Makefile.test_util.include.

Not sure if another Makefile would be allowed, but before I expand the already existing (and complex) ones, I think a small, separate Makefile is better.

Here the link to the commit in my forked repo: https://github.com/brakmic/bitcoin/commit/3f4b5e3a0b93c6b528bf707fd38eb63c0e29efa9

I'm working on macOS Catalina 10.15.1 with clang 9.0.0.

Regards,

[maflcko]

Overall looks good, but the bench and gui tests are not using it?

[brakmic]

Thanks!
I've included the missing references in bench & qttest.

Here's the commit: https://github.com/brakmic/bitcoin/commit/03002e3683c05dbd769efc7b2df206e0798bab3a

I've compiled bench/qttest and could execute them.

[brakmic]

Oops, have forgotten to remove TEST_BITCOIN_H. Will do it now.

[brakmic]

Done.

https://github.com/brakmic/bitcoin/commit/10c270bf5b0d5f444f6178592330320710b27261

[maflcko]

Ok, looks like you can open a pull request to get more review on it 👍

[brakmic]

Many thanks. Will look into contribution guide first. ;)