std.testing: add methods tmpDirPath, getTestArgs, buildExe

continuation of #11093 to simplify testing IPC

* use cases
  - get path to temporary directory
  - get the test arguments inside test block for reusage
  - build executables from text within test blocks, ie to test IPC
* missing conventions
  - how to name and debug test cases
  - where do simple+repititve build commands for testing belong
dbbda0f41amatu3ba committed on 3/27/2022, 8:43:40 AM· committed by GitHubparentf9a2c0f
2 files changedLine totals unavailable