Merge branch 'js/add-i-a-bit-more-tests'

Test coverage update in preparation for further work on "git add -i". * js/add-i-a-bit-more-tests: apply --allow-overlap: fix a corner case git add -p: use non-zero exit code when the diff generation failed t3701: verify that the diff.algorithm config setting is handled t3701: verify the shown messages when nothing can be added t3701: add a test for the different `add -p` prompts t3701: avoid depending on the TTY prerequisite t3701: add a test for advanced split-hunk editing