Fix config struct processing, add (much needed) tests

Added:

- Tests (partial implementation/coverage)
  - validate the most common code-paths (much more TODO)
    - config handling
    - logging setup
  - run tests as part of GitHub Actions Workflow
    - recursively
    - after getting deps, but before linting steps
      in order to allow early failure
  - update Makefile to run tests recursively, verbosely
- Fix configuration precedence handling
- Add string slice equality check from StackOverflow

Changed:

- Fix configuration precedence handling
  - Config file loses to everything except default config settings
- `config.logBuffer` moved to `logging.LogBuffer`
  - internal detail exposed for general use
    - may change this later
- Updated code (where apparent) to be more test friendly
  - e.g., use `io.Reader` instead of filename so that we can use
    an in-memory TOML config file for testing config parsing
    and precedence validation
- Split config package into smaller files in an effort to make
  related code easier to manage
- Fail if requested config file not found
  - previously an error was logged, but execution was allowed
    to continue.
- Move default values to Getter methods
  - use those methods instead of directly dereferencing config
    struct fields in the majority of the code
  - use Getter methods to guard against nil dereferences
- Partial work to de-couple reliance on `Config{}` (see #170)

Deprecated:

Both of these functions from the `config` package do not appear
to be needed any longer, but are being kept for a cycle in case
I change my mind:

- `Config.SetDefaultConfig()`
- `Config.GetStructTag()`

Fixed:

- Fix configuration precedence handling
  - Config settings are merged properly, so that even default
    settings are allowed to override lower precedence config
    sources
- NumFilesToKeep default (didn't match v0.5.1 change)
- Add missing `default` switch statements along with error
  return codes for `Set` functions with specific valid option values
- README updates
  - cover config file flag, environment variables
  - config precedence corrections
- Multiple linting errors (with more that needs to be evaluated)
- Add missing exit if IgnoreErrors is false
- Handle unintended nil assignment
- Update GoDoc doc file
  - reflect config file support, including updated Help text

TODO:

- Update multiple tests to use "tables" instead of hard-coding
  specific checks (which ends up being very lengthy)
  - e.g., `TestValidate()`

refs #161, #156, #170

COMMITS.LOG

@@ -0,0 +1,114 @@
+785850d Remove scatch notes used to setup config tests
+3b53749 Doc updates that attempt to fix precedence details to match current implementation
+a4f1dc6 Stub out TestEnableSyslogLogging func, add missing default switch statement
+cf5c728 Replace actual phrasing with got to be more idomatic
+b904432 WIP: AppMetadata fields are no longer user configurable
+c83db6b Finished testing complete and incomplete config struct merges
+43d30f5 WIP: Partial work towards testing complete and incomplete config struct merges
+6819d94 WIP: Partial work towards testing complete and incomplete config struct merges
+ef6847f WIP: Update MergeConfig() to bring over ConfigFile values if set in source config
+3ec8b99 WIP: First stab at implementing flags config testing. The ConfigFile bits are still problematic
+71d4561 Update example FileExtensions entries to reflect env vars spacing requirements
+d295d13 Reactivate TestMergeConfig
+cee725b Fix unintentional space in extensions slice, update formatting of test output to quote slice entries to make mistakes like this easier to spot
+d9fcd83 Defer env var unset via anonymous func
+cd883cc Unset env vars after we are done using them for testing
+a2a0200 Fix MergeConfigTest() call, args
+4bc6283 Fix log level setting
+2bc6b45 Stub in MergeConfigTest() call
+79a6d01 WIP: Disable TestMergeConfig(), begin stubbing out standard function to temporarily replace it
+4a86a17 WIP: Attempt to stub in env var config test content
+cadd5d1 README: Add coverage for conf file env var, flag
+8930ac7 Update TODO items for remaining TestMergeConfig work
+b52cd27 Add NOTICE.txt entry for stackoverflow example code
+f021ad3 WIP: Add CompareConfig, testStringSliceEqual funcs, use them
+b8bddc5 WIP: Prepping to build fileConfig to match scratch notes
+b8e0017 Fix doc comment to indicate correct field and note why it needs to be initialized
+1bb393f Finish first draft of merge test planning
+fa4253c Specify FileExtensions, note why we will do so. Update Test function name
+1c5eeee Add more scratch notes likely to be folded into the main README later
+c4f5e8a Add scratch notes to be pruned/merged later
+2ff1f17 Add TODO items for follow-up
+c589b2f Add MergeConfig() test, update existing tests
+a88c95c Add TODO notes for later work
+407aef1 Clarify doc comment
+19407b6 Update tests to use local copy of test values
+be7332a Move default in-memory config to global test var
+7fba570 Fix config file load/validation tests
+e56453d Fix tests by switching logic on whether file exists
+8a37ac5 Add tests for loading config file
+0013b81 Add config/deprecated.go that was meant to go in a few commits back
+6af8d29 Update config.LoadConfigFile to use io.Reader instead of filename
+565586f Add FIXME for breaking dependency on config package
+d10ac50 Finish moving code to deprecated.go
+3cd84a5 Formatting tweaks for potential nil err
+d71f5a5 Update Makefile to run go tests recursively, verbosely
+23a6b94 Doc comment tweaks
+f079327 Add explicit note that we're proceeding with evaluation of argsConfig after fileConfig validation failure
+08d2dc2 Allow fileConfig post-merge validation failure
+f8d1b30 Nevermind, going to try just making fileConfig validation a non-fatal status
+5cc575a Fix tests to match last code change
+4a424f0 Testing lighter Validate() enforcement
+531bcad Fix goconst linting error
+3a2ae1d WIP: Add TODO re calling Validate() against fileConfig post-merge
+e198739 Move Validate() tests to dedicated file
+dd774fb WIP: Finished Validate() tests?
+ce8d608 WIP: Crafting Validate() tests
+bb22d5e WIP: Crafting Validate() tests, fix Validate()
+b0e40ef WIP: Crafting Validate() tests | KeepOldest, Remove, IgnoreErrors
+4d6b4bc WIP: Crafting Validate() tests | FileAge
+897e184 WIP: Crafting Validate() tests
+172cc1c WIP: Crafting Validate() tests, fix Validate()
+390a16f WIP: Crafting Validate() tests
+2236140 WIP: Crafting Validate() tests
+5c62376 Update config.Validate() to only return err/nil instead of bool + err/nil
+358715f Add TODO item for later
+8fb1bc1 Fix invalid assignment in MergeConfig()
+d25b717 TESTS | Add coverage for LogBuffer.Flush()
+b25f1d1 Prune old scratch doc comments
+29fdc9d Update several logging methods to be test friendly
+0e98dd2 TESTS | Add tests for SetLoggerConsoleOutput()
+ae33e15 TESTING | Add tests for SetLoggerLevel
+c5882da GitHub Actions Workflow: Run go tests
+f297916 TESTS: Experiment with adding tests
+5c939f6 Add stubbed out print statements proving os.Args does not contain quoting
+88bf604 Log os.Args as first item in NewConfig()
+b5ba232 Prune unused test code
+df4c37d Split config.go into multiple sibling files
+514083d Move package global logBuffer from config to logging package
+c8ab59e Update doc comments, fail if requested config file not found
+06c06be Miscellaneous cleanup, replace direct derefs
+c91b1f5 Add missing exit if IgnoreErrors is false
+3f0cd9b Fix prototype test file to accomodate NewConfig() changes
+b40abf2 Update log level for merge failure messages, create help text writer func
+3d9d2e2 WIP: Saving progress passing error handling to main()
+e1aa4fe Prototyping panic behavior after post-merge config validation failure
+597eee9 Tweak panic message for logger level default case
+43ad767 SUCCESS! Found unintended nil assignment due to unhandled code path
+9952ccc WIP: Still broken, saving status
+71db887 WIP: Add untested handling of failed config validation
+132d0c0 TODO: Fix config validation error handling
+544469a WIP: Further troubleshooting
+67b4435 WIP: Created SetDefaultConfig() method, minor tweaks, update String() method to use Getter methods
+d20382e Saving progress
+3c128c4 Move default values to Getter methods, use infamous new() func to initialize field pointers
+1d5e35a Create defaultXYZ config struct fields; experimenting
+0049cf8 Move AppMetadata values with other defaults (missed test file)
+025a4a5 Move AppMetadata values with other defaults
+94bdd1b Restore NumFilesToKeep default to match v0.5.1 change
+d212e8a Add TODO re default values
+9e26da2 Add back AppVersion, extend Validate() method
+92fda99 Use GetUseSyslog() getter to restore flag value logging
+3afd3ae Use non-pointer string slice fields for Paths, FileExtensions
+7a364a4 Direct nil check on c.Paths instead of using Getter
+8e34159 Fix several nil pointer derefs
+46e85c2 WIP: Untested adjustments guided by Twitter feedback
+189d628 Fix method call ref
+6d18365 WIP: More fixes related to Getter methods
+b70a385 WIP: More fixes to make use of Getter methods
+0e75133 WIP: Set fileConfig and argsConfig to uninit structs
+f8405e5 WIP: Finish Getter methods, much left to do
+1a03244 Ignore local 'scratch' directory
+e8fff5c WIP: Still broken, still rerranging the pieces
+2c6227b WIP: Working on Getter methods
+291bfe9 WIP: Need to build Getter methods next, replace direct access

COMMITS_PR_Message.txt

@@ -0,0 +1,68 @@
+Fix config struct processing, add (much needed) tests
+
+Added:
+
+- Tests (partial implementation/coverage)
+  - validate the most common code-paths (much more TODO)
+    - config handling
+    - logging setup
+  - run tests as part of GitHub Actions Workflow
+  - update Makefile to run tests recursively, verbosely
+- Fix configuration precedence handling
+- Add string slice equality check from StackOverflow
+
+
+Changed:
+
+- Fix configuration precedence handling
+  - Config file loses to everything except default config settings
+- `config.logBuffer` moved to `logging.LogBuffer`
+  - internal detail exposed for general use
+    - may change this later
+- Updated code (where apparent) to be more test friendly
+  - e.g., use `io.Reader` instead of filename so that we can use
+    an in-memory TOML config file for testing config parsing
+    and precedence validation
+- Split config package into smaller files in an effort to make related
+  code easier to manage
+- Fail if requested config file not found
+  - previously an error was logged, but execution was allowed
+    to continue.
+- Move default values to Getter methods
+  - use those methods instead of directly dereferencing config
+    struct fields in the majority of the code
+  - use Getter methods to guard against nil dereferences
+
+
+Deprecated:
+
+Both of these functions from the `config` package do not appear
+to be needed any longer, but are being kept for a cycle in case
+I change my mind:
+
+- `Config.SetDefaultConfig()`
+- `Config.GetStructTag()`
+
+
+Fixed:
+
+- Fix configuration precedence handling
+  - Config settings are merged properly, so that even default
+    settings are allowed to override lower precedence config sources
+- NumFilesToKeep default (didn't match v0.5.1 change)
+- Add missing `default` switch statements along with error
+  return codes for `Set` functions with specific valid option values
+- README updates
+  - cover config file flag, environment variables
+  - config precedence corrections
+- Multiple linting errors (with more that needs to be evaluated)
+- Add missing exit if IgnoreErrors is false
+- Handle unintended nil assignment
+- Update GoDoc doc file
+  - reflect config file support, including updated Help text
+
+TODO:
+
+- Update multiple tests to use "tables" instead of hard-coding
+  specific checks (which ends up being very lengthy)
+  - e.g., `TestValidate()`