* ci: run stable tests partially
* ci: improve uploading test result
* use buildkite's retry
* test common
* fix indent issue
* extract assert eq
* use diff to print test error
* pretty format
* test build stable steps
* add test all function
* lint
* lint
* keep dollar sign
* switch got and want's diff direction
* use 'EOF' to make code more readable
* rename EMPTY_LINE to DELETE_THIS_LINE
* rename N => INDEX
* rename M => LIMIT
* check variable in a more elegant way
* wording
* more explain for code