Split init / exec of tmux_cmd for debuggability

[tony]

Edit 2022-08-14 by @tony : This is very similar to SubprocessCommand (source)

tmux_cmd initialization composes the command

the command will be available in the instance attribute .cmd

.execute() instance method will run tmux_cmd

See Server.cmd for example of new usage

Related #77

[tony]

This, as of c9598fb doesn't touch any of the Server/Session/Window/Pane .cmd method API's.

As a second part of this, I may add more things to split introspection of commands.

For instance:

• Renaming tmux_cmd to TmuxCommand

• Documenting how they are composed and can be configured, and why/how it's differs from standard library subprocess

• Methods in Tmux objects, e.g. attach_session() may have a way to return the pure TmuxCommand object (and therefore preview the command generated, including the valuable target information (-t))

• as a way the above could be implemented, it may be via adding methods like _attach_session() that return TmuxCommand and having attach_session wrap them and keep normal behavior

• Another thing to consider is to break api's by requiring .execute() be ran to execute commands, and return TmuxCommand by default

• BUT, allow for chaining commands. e.g., session.attached_window.set_window_option('main-pane-height', 50).select_layout('main-horizontal').execute(), this would give the equivalent to chaining commands with semicolons. This could substantially speed things up by allowing for composability with commands.

[codecov-io]

Codecov Report

❌ Patch coverage is 85.71429% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.04%. Comparing base (02fe5d6) to head (8e00da8).
⚠️ Report is 1730 commits behind head on master.

Files with missing lines	Patch %	Lines
tests/test_common.py	80.95%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #79      +/-   ##
==========================================
- Coverage   88.13%   88.04%   -0.09%     
==========================================
  Files          15       15              
  Lines        1500     1523      +23     
==========================================
+ Hits         1322     1341      +19     
- Misses        178      182       +4     

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[tony]

This is very similar to SubprocessCommand (source)