1 files changed, 34 insertions, 0 deletions
diff --git a/flagset_test.go b/flagset_test.go
new file mode 100644
index 0000000..bef4dd2
--- /dev/null
+++ b/flagset_test.go
@@ -0,0 +1,34 @@
+// SPDX-FileCopyrightText: 2020 Ethel Morgan
+//
+// SPDX-License-Identifier: MIT
+
+package flag
+
+import (
+	"testing"
+	"time"
+)
+
+func TestFlagSetCustom(t *testing.T) {
+	fs := NewFlagSet("test", ContinueOnError)
+
+	i := fs.Int("i", 0, "i")
+	d := fs.Custom("d", "1s", "d", func(raw string) (interface{}, error) {
+		return time.ParseDuration(raw)
+	})
+	e := fs.Custom("e", "", "e", StringEnum("json", "table"))
+
+	if err := fs.Parse([]string{"-i", "12", "-d", "3m", "-e", "json"}); err != nil {
+		t.Fatalf("got error: %v", err)
+	}
+
+	if *i != 12 {
+		t.Errorf("-i == %v, wanted %v", *i, 12)
+	}
+	if (*d).(time.Duration) != 3*time.Minute {
+		t.Errorf("-d == %v, wanted %v", *d, 3*time.Minute)
+	}
+	if (*e).(string) != "json" {
+		t.Errorf("-e == %v, wanted %v", *e, "json")
+	}
+}