Merge branch 'ld/sparse-index-bash-completion'

Test regression fix.

* ld/sparse-index-bash-completion:
  t9902: split test to run on appropriate systems

t/t9902-completion.sh

@@ -1529,28 +1529,45 @@ test_expect_success 'cone mode sparse-checkout completes directory names with sp
 	)
 '
 
-# use FUNNYNAMES to avoid running on Windows, which doesn't permit backslashes or tabs in paths
-test_expect_success FUNNYNAMES 'cone mode sparse-checkout completes directory names with backslashes and tabs' '
+# use FUNNYNAMES to avoid running on Windows, which doesn't permit tabs in paths
+test_expect_success FUNNYNAMES 'cone mode sparse-checkout completes directory names with tabs' '
 	# reset sparse-checkout
 	git -C sparse-checkout sparse-checkout disable &&
 	(
 		cd sparse-checkout &&
-		mkdir "directory\with\backslashes" &&
 		mkdir "$(printf "directory\twith\ttabs")" &&
-		>"directory\with\backslashes/randomfile" &&
 		>"$(printf "directory\twith\ttabs")/randomfile" &&
 		git add . &&
-		git commit -m "Add directory with backslashes and directory with tabs" &&
-		git sparse-checkout set --cone "directory\with\backslashes" \
+		git commit -m "Add directory with tabs" &&
+		git sparse-checkout set --cone \
 			"$(printf "directory\twith\ttabs")" &&
 		test_completion "git sparse-checkout add dir" <<-\EOF &&
-		directory\with\backslashes/
 		directory	with	tabs/
 		EOF
-		rm -rf "directory\with\backslashes" &&
 		rm -rf "$(printf "directory\twith\ttabs")" &&
 		git add . &&
-		git commit -m "Remove directory with backslashes and directory with tabs"
+		git commit -m "Remove directory with tabs"
+	)
+'
+
+# use FUNNYNAMES to avoid running on Windows, and !CYGWIN for Cygwin, as neither permit backslashes in paths
+test_expect_success FUNNYNAMES,!CYGWIN 'cone mode sparse-checkout completes directory names with backslashes' '
+	# reset sparse-checkout
+	git -C sparse-checkout sparse-checkout disable &&
+	(
+		cd sparse-checkout &&
+		mkdir "directory\with\backslashes" &&
+		>"directory\with\backslashes/randomfile" &&
+		git add . &&
+		git commit -m "Add directory with backslashes" &&
+		git sparse-checkout set --cone \
+			"directory\with\backslashes" &&
+		test_completion "git sparse-checkout add dir" <<-\EOF &&
+		directory\with\backslashes/
+		EOF
+		rm -rf "directory\with\backslashes" &&
+		git add . &&
+		git commit -m "Remove directory with backslashes"
 	)
 '