Add test for strings.go

internal/util/strings_test.go

@@ -6,6 +6,15 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+func TestContainsNumber(t *testing.T) {
+	t.Run("True", func(t *testing.T) {
+		assert.Equal(t, true, ContainsNumber("f3abcde"))
+	})
+	t.Run("False", func(t *testing.T) {
+		assert.Equal(t, false, ContainsNumber("abcd"))
+	})
+}
+
 func TestIsSeparator(t *testing.T) {
 	t.Run("rune A", func(t *testing.T) {
 		assert.Equal(t, false, isSeparator('A'))