       {at: 2, expect: "minmax(30px, 3fr) minmax(40px, auto)"}
      ]);

      test_interpolation({
        property: 'grid-template-columns',
        from: "10px 10px 10px",
        to: "1fr fit-content(20px) minmax(20px, 2fr)"
      }, [
        {at: -1, expect: "10px 10px 10px"},
        {at: 0, expect: "10px 10px 10px"},
        {at: 0.4, expect: "10px 10px 10px"},
        {at: 0.6, expect: "1fr fit-content(20px) minmax(20px, 2fr)"},
        {at: 1, expect: "1fr fit-content(20px) minmax(20px, 2fr)"},
 