Under normal circumstances, `rake -m test` will parallelize not only the build task, but also the test task.
With this patch, `rake -m test:run:serial` will parallelize the build tasks, but the test tasks will be done one by one in sequence.
The name of the task to be added is as follows:
| tasks to be added | corresponding exist tasks
| --------------------- | ----------------
| `test:run:serial` | `test:run`
| `test:run:serial:bin` | `test:run:bin`
| `test:run:serial:lib` | `test:run:lib`
With this change, the test code will not be built unless `rake test` is
run, so there will be almost no side effects even if `enable_test` is
always set (but, gems specified by `add_test_dependency` are included
in `libmruby.a`).
Also added are `test: build` task, which only builds the test code
(including the main code), and `test: run` task, which only runs tests
independent of build. Therefore, the idiom for building in parallel and
not running tests in parallel is `rake -m test:build && rake test:run`.
Currently, there are build configuration files for CI, `travis.rb` and
`appveyor.rb`, but they are used for GCC/Clang and MSVC, not for Travis CI
and Appveyor, respectively.
Therefore, rename them to `gcc-clang.rb` and `msvc.rb`, respectively, and
move them under `build_config/ci/` to clarify that they are for CI.
* In explanation of mruby, the expression `build_config.rb` is frequently
used including official documents, so I think that it will not make sense
if the file is no longer used.
* The `MRUBY_TARGET` mechanism seems to have little improvement, so I don't
think it should be changed to avoid unnecessary confusion.
* `MRUBY_TARGET` and `MRuby.targets` represent somewhat different things,
so using the same term "target" is a bit confusing.
The mechanism that can be written short when using a file under
`build_config` (renamed from `target`) directory remains
(`build_config/${MRUBY_CONFIG}.rb` is used if the path specified
in `MRUBY_CONFIG` doesn't exist).
The following error occurs when using `rake -m` on AppVeyor:
```
fatal error C1041: cannot open program database 'C:\projects\mruby\vc140.pdb'; if multiple CL.EXE write to the same .PDB file, please use /FS
```
Therefore, the issue is solved by not creating the PDB file. It is expected
to be somewhat faster by not generating debugging information (I don't think
debugging information is necessary for normal CI).
dearblue