checkout-index: expand sparse checkout compatibility tests

Add tests to cover `checkout-index`, with a focus on cases interesting in a
sparse checkout (e.g., files specified outside sparse checkout definition).

New tests are intended to serve as a baseline for existing and/or expected
behavior and performance when integrating `checkout-index` with the sparse
index. Note that the test 'checkout-index --all' is marked as
'test_expect_failure', indicating that `update-index --all` will be modified
in a subsequent patch to behave as the test expects.

Signed-off-by: Victoria Dye <[email protected]>
Reviewed-by: Elijah Newren <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: vdye

t/perf/p2000-sparse-operations.sh

@@ -117,5 +117,6 @@ test_perf_on_all git diff
 test_perf_on_all git diff --cached
 test_perf_on_all git blame $SPARSE_CONE/a
 test_perf_on_all git blame $SPARSE_CONE/f3/a
+test_perf_on_all git checkout-index -f --all
 
 test_done

t/t1092-sparse-checkout-compatibility.sh

@@ -755,6 +755,60 @@ test_expect_success 'cherry-pick with conflicts' '
 	test_all_match test_must_fail git cherry-pick to-cherry-pick
 '
 
+test_expect_success 'checkout-index inside sparse definition' '
+	init_repos &&
+
+	run_on_all rm -f deep/a &&
+	test_all_match git checkout-index -- deep/a &&
+	test_all_match git status --porcelain=v2 &&
+
+	echo test >>new-a &&
+	run_on_all cp ../new-a a &&
+	test_all_match test_must_fail git checkout-index -- a &&
+	test_all_match git checkout-index -f -- a &&
+	test_all_match git status --porcelain=v2
+'
+
+test_expect_success 'checkout-index outside sparse definition' '
+	init_repos &&
+
+	# File does not exist on disk yet for sparse checkouts, so checkout-index
+	# succeeds without -f
+	test_sparse_match git checkout-index -- folder1/a &&
+	test_cmp sparse-checkout/folder1/a sparse-index/folder1/a &&
+	test_cmp sparse-checkout/folder1/a full-checkout/folder1/a &&
+
+	run_on_sparse rm -rf folder1 &&
+	echo test >new-a &&
+	run_on_sparse mkdir -p folder1 &&
+	run_on_all cp ../new-a folder1/a &&
+
+	test_all_match test_must_fail git checkout-index -- folder1/a &&
+	test_all_match git checkout-index -f -- folder1/a &&
+	test_cmp sparse-checkout/folder1/a sparse-index/folder1/a &&
+	test_cmp sparse-checkout/folder1/a full-checkout/folder1/a
+'
+
+test_expect_success 'checkout-index with folders' '
+	init_repos &&
+
+	# Inside checkout definition
+	test_all_match test_must_fail git checkout-index -f -- deep/ &&
+
+	# Outside checkout definition
+	test_all_match test_must_fail git checkout-index -f -- folder1/
+'
+
+# NEEDSWORK: even in sparse checkouts, checkout-index --all will create all
+# files (even those outside the sparse definition) on disk. However, these files
+# don't appear in the percentage of tracked files in git status.
+test_expect_failure 'checkout-index --all' '
+	init_repos &&
+
+	test_all_match git checkout-index --all &&
+	test_sparse_match test_path_is_missing folder1
+'
+
 test_expect_success 'clean' '
 	init_repos &&