installer library fixes/tests

[mm-pagely]

New things

• I added test suites for our bash code that run on bats. There's a helper library in tests/bash/helpers.bash with extensions so you can do nice things like:

  run commandIWantToTest $arg1 $arg2
  assert equal 0 $status
  assert stringContains "some output" "$output"

• Also added is bash linting via shellcheck. There's a commented .shellcheckrc file for anyone who wants to use those same settings in their editor.

Changes

• I totally abandoned any attempted usage of sudo. It's just too scary. Instead the installer checks write perms on all known paths for and bails out very early on if there's a problem.

[2019-06-25 16:34:36] [error] Could not verify the minimum installation requirements for your system
[2019-06-25 16:34:36] [error] BINARY_PATH errors:
[2019-06-25 16:34:36] [error]   * binary path (/root/local/bin/northstack) does not exist, and its parent (/root) is not writable.
[2019-06-25 16:34:36] [error]   * File: /root
[2019-06-25 16:34:36] [error]   * Type: directory
[2019-06-25 16:34:36] [error]   * Mode: (550 / dr-xr-x---)
[2019-06-25 16:34:36] [error]   * Owner: (0 / root)
[2019-06-25 16:34:36] [error]   * Group: (0 / root)
[2019-06-25 16:34:36] [error] LIBRARY_PATH errors:
[2019-06-25 16:34:36] [error]   * library path (/root/local/northstack) does not exist, and its parent (/root) is not writable.
[2019-06-25 16:34:36] [error]   * File: /root
[2019-06-25 16:34:36] [error]   * Type: directory
[2019-06-25 16:34:36] [error]   * Mode: (550 / dr-xr-x---)
[2019-06-25 16:34:36] [error]   * Owner: (0 / root)
[2019-06-25 16:34:36] [error]   * Group: (0 / root)

• We're still using helper functions for most file operations (i.e. cp, rm, ln, etc) because they run things by a helper function assertSafePath just to sanity check.

What remains

At this point I still need to spend some time testing on Mac to sort out the GNU vs BSD coreutils madness.