refactor: update substitute tests to use table syntax

[JordanSussman]

changes

• Updates the existing substitute tests to utilize table tests
• Update the SubstituteSteps test to include another test case for templates

[codecov]

Codecov Report

Merging #653 (8405882) into master (7dbbc86) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #653   +/-   ##
=======================================
  Coverage   55.07%   55.07%           
=======================================
  Files         195      195           
  Lines       15926    15926           
=======================================
  Hits         8771     8771           
  Misses       6781     6781           
  Partials      374      374           

[wass3r]

looks like the test is failing :( unless that's the intent ?

[JordanSussman]

@wass3r this was originally created to showcase that the default variable substitution syntax ${var:-default} does not appear to work outside of commands. Talking with @jbrockopp we realized the following:

• Some variables do not get set until a build runs on the worker
• The server attempts to make best efforts to substitute all variables available to it at the time
• If a variable isn't set, then assume it may be set by the worker so it "puts it back"

The existing behavior is fine for most use-case but if you're trying to do variable substitution for vars passed to a template, you're going have a bad time. Thinking about opening up a new issue to talk through possible changes to this behavior to allow default syntax to be used.

[jbrockopp]

LGTM