diff --git a/example/flag.yaml b/example/flag.yaml
new file mode 100644
index 0000000..a99617d
--- /dev/null
+++ b/example/flag.yaml
@@ -0,0 +1,11 @@
+name: flag
+flags:
+  --hidden&: hidden
+  --hidden-arg&=: hidden with argument
+  --hidden-opt&?: hidden with optional argument
+  --repeatable*: repeatable
+  --required!: required
+completion:
+  flag:
+    hidden-arg: [h1, h2]
+    hidden-opt: [ho1, ho2]
diff --git a/flag_test.go b/flag_test.go
index 91d1a4e..f3ed21d 100644
--- a/flag_test.go
+++ b/flag_test.go
@@ -1,9 +1,12 @@
 package spec
 
 import (
+	_ "embed"
 	"reflect"
 	"testing"
 
+	"github.com/rsteube/carapace"
+	"github.com/rsteube/carapace/pkg/sandbox"
 	"github.com/spf13/pflag"
 )
 
@@ -119,3 +122,33 @@ func TestParseFlag(t *testing.T) {
 		nameAsShorthand: false,
 	})
 }
+
+//go:embed example/flag.yaml
+var flagSpec string
+
+func TestFlag(t *testing.T) {
+	sandboxSpec(t, flagSpec)(func(s *sandbox.Sandbox) {
+		s.Run("--hidden").
+			Expect(carapace.ActionValues().
+				NoSpace('.'))
+
+		s.Run("--hidden-arg", "").
+			Expect(carapace.ActionValues(
+				"h1",
+				"h2",
+			).Usage("hidden with argument"))
+
+		s.Run("--hidden-opt=").
+			Expect(carapace.ActionValues(
+				"ho1",
+				"ho2",
+			).Prefix("--hidden-opt=").
+				Usage("hidden with optional argument"))
+
+		s.Run("--repeatable", "--repeat").
+			Expect(carapace.ActionValuesDescribed(
+				"--repeatable", "repeatable",
+			).NoSpace('.').
+				Tag("flags"))
+	})
+}