[PATCH v3 1/2] t1092: add tests for `git diff-files`

[Shuqi Liang <cheskaqiqi@gmail.com>]

Before integrating the 'git diff-files' builtin
with the sparse index feature, add tests to
t1092-sparse-checkout-compatibility.sh to ensure it currently works
with sparse-checkout and will still work with sparse index
after that integration.

When adding tests against a sparse-checkout
definition, we test two modes: all changes are
within the sparse-checkout cone and some changes are outside
the sparse-checkout cone.

In order to have staged changes outside of
the sparse-checkout cone, create a 'newdirectory/testfile' and
add it to the index, while leaving it outside of
the sparse-checkout definition.Test 'newdirectory/testfile'
being present on-disk without modifications, then change content inside
'newdirectory/testfile' in order to test 'newdirectory/testfile'
being present on-disk with modifications.

Signed-off-by: Shuqi Liang <cheskaqiqi@gmail.com>
---
 t/t1092-sparse-checkout-compatibility.sh | 40 ++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh
index 801919009e..bdf3cf25d4 100755
--- a/t/t1092-sparse-checkout-compatibility.sh
+++ b/t/t1092-sparse-checkout-compatibility.sh
@@ -2055,4 +2055,44 @@ test_expect_success 'grep sparse directory within submodules' '
 	test_cmp actual expect
 '
 
+test_expect_success 'diff-files with pathspec inside sparse definition' '
+	init_repos &&
+
+	write_script edit-contents <<-\EOF &&
+	echo text >>"$1"
+	EOF
+
+	run_on_all ../edit-contents deep/a &&
+
+	test_all_match git diff-files  &&
+	test_all_match git diff-files deep/a 
+'
+
+test_expect_success 'diff-files with pathspec outside sparse definition' '
+	init_repos &&
+
+	write_script edit-contents <<-\EOF &&
+	echo text >>"$1"
+	EOF
+
+	# add file to the index but outside of cone
+	run_on_sparse mkdir newdirectory &&
+	run_on_sparse ../edit-contents newdirectory/testfile &&
+	test_sparse_match git add --sparse newdirectory/testfile &&
+
+	# file present on-disk without modifications
+	test_sparse_match git diff-files &&
+	! test_file_not_empty sparse-checkout-out &&
+	! test_file_not_empty sparse-index-out &&
+	test_sparse_match git diff-files newdirectory/testfile &&
+	! test_file_not_empty sparse-checkout-out &&
+	! test_file_not_empty sparse-index-out &&
+
+	# file present on-disk with modifications
+	run_on_sparse ../edit-contents newdirectory/testfile &&
+	test_sparse_match git diff-files &&
+	test_sparse_match git diff-files newdirectory/testfile &&
+	test_file_not_empty sparse-checkout-out
+'
+
 test_done
-- 
2.39.0