test(scp): add coverage for -n/--dry-run and -i/--interactive abort

git-scp had no test coverage at all. Cover the two paths that need no
real remote destination: dry-run must preview without touching the
index, working tree, or remote path, and declining the interactive
confirmation must abort before anything syncs.

tests/git-scp.bats

@@ -0,0 +1,46 @@
+# shellcheck shell=bash
+
+source "$BATS_TEST_DIRNAME/test_util.sh"
+
+setup_file() {
+	test_util.setup_file
+}
+
+setup() {
+	test_util.cd_test
+
+	test_util.git_init
+	printf '%s\n' 'hello' > tracked.txt
+	git add tracked.txt
+	git commit -m 'Initial commit'
+
+	# never created: neither test below should ever touch it
+	git remote add fake "$BATS_TEST_TMPDIR/never-created"
+
+	printf '%s\n' 'world' >> tracked.txt
+}
+
+@test "dry-run previews the sync without changing anything" {
+	run git scp -n fake
+	assert_success
+	assert_line -p 'tracked.txt'
+	assert_line -p 'DRY RUN'
+
+	run git status --short
+	assert_line -p 'M tracked.txt'
+
+	run test -e "$BATS_TEST_TMPDIR/never-created"
+	assert_failure
+}
+
+@test "interactive mode aborts without syncing when declined" {
+	run bash -c 'echo n | git scp -i fake'
+	assert_success
+	assert_line -p 'Aborted, nothing synced.'
+
+	run git status --short
+	assert_line -p 'M tracked.txt'
+
+	run test -e "$BATS_TEST_TMPDIR/never-created"
+	assert_failure
+}