フリー問題

問題文

A team wants automated confidence that a change to a shared library does not break its callers. Which practice gives that confidence earliest?

選択肢

1. Add usage examples to the shared library and block the merge when the test run fails on any commit.
2. Add unit tests to the shared library and block the merge when the style check fails on any commit.
3. Add usage examples to the shared library and block the merge when the style check fails on any commit.
4. Add unit tests to the shared library and block the merge when the test run fails on any commit.