Cassette config inheritance

[aaronwolen]

As discussed in #151. This changes the defaults for arguments in use_cassette()/insert_cassette() to NULL if they control parameters that are also configurable via VCRConfig. Before making this change I reformatted the code so there's only one argument per line to make the diff more readable.

Other changes:

• Adds test helper vcr_test_configuration() to reset the current configuration and restore settings that should be in place for all tests. This could be called within a teardown() block at the top of every test file that includes modifications to the configuration. Currently it's only used in the new inheritance tests.
• Adds tests to verify that cassettes inherit settings from vcr_configuration()

[codecov-io]

Codecov Report

Merging #153 into master will increase coverage by 1.6%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master     #153     +/-   ##
=========================================
+ Coverage    73.9%   75.51%   +1.6%     
=========================================
  Files          36       36             
  Lines        1506     1511      +5     
=========================================
+ Hits         1113     1141     +28     
+ Misses        393      370     -23

Impacted Files	Coverage Δ
R/configuration.R	36.84% <ø> (+20.17%)	⬆️
R/use_cassette.R	100% <100%> (ø)	⬆️
R/insert_cassette.R	93.1% <100%> (+0.79%)	⬆️

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[sckott]

All looks good, except:

We should update the parameter docs for insert_cassette and use_cassette for those that are changed in this PR to say that their default values are set by vcr_configure - which only needs to be done in use_cassette i guess since insert_cassette inherits from use_cassette

[sckott]

And document - make it explicit that any parameters set in insert_cassette/use_cassette override those set with vcr_configure

[aaronwolen]

Cool, I'll work on updating the docs.

[aaronwolen]

I took a stab at documenting the new inheritance behavior in
6d033a7 but I feel like it could be clearer. That was the best my brain could come up with late on a Friday afternoon 🙂. Let me know if you have any suggestions. Otherwise I'll make another pass on Monday.

[sckott]

looks good to me - can you resolve the conflict, then i can merge

[aaronwolen]

Thanks for looking it over. I made a few additional non-coding changes that include some minor rewording/reorgs in the docs. Suggesting looking over

• 3108f76 to see if you agree with the rewording
• cb23594, which reorganizes the configuration docs a bit to create a separate section for cassette options that can be configured both globally and locally—and added a brief description that attempts to explain how they relate to each other.

Also just rebased to sync up with master.

[sckott]

Both look good, thanks.