Expainning all config from rspec_helper.rb file

rspec_helper_config.md

Line	Meaning
RSpec.configure do	Opens the RSpec configuration block — all settings go inside this.
config.expect_with :rspec do	Configures how expectations (expect) work.
expectations.include_..._descriptions = true	Improves custom matcher messages by including chained conditions for clearer failure output.
config.mock_with :rspec do	Configures RSpec’s mocking framework.
mocks.verify_partial_doubles = true	Ensures mocked/stubbed methods exist on real objects — prevents invalid stubs or typos.
config.shared_..._behavior = :apply_to_host_groups	Makes metadata from shared contexts automatically apply to groups using them.
config.filter_run_when_matching :focus	Runs only tests marked with :focus — useful for debugging specific examples.
config....persistence_file_path = "spec/examples.txt"	Saves test results so RSpec can re-run only failed examples using --only-failures.
config.disable_monkey_patching!	Prevents RSpec from adding global methods like describe outside its namespace — keeps Ruby clean.
if config.files_to_run.one?	Checks if only one spec file is being executed.
config.default_formatter = "doc"	Uses the “documentation” formatter for readable output when running one file.
# config.profile_examples = 10	(Commented) Would show the 10 slowest tests — useful for performance profiling.
config.order = :random	Runs specs in random order to reveal hidden dependencies.
Kernel.srand config.seed	Seeds Ruby’s random generator so test order can be reproduced.
end	Closes the RSpec.configure block.