### Question:
GridSurfaceInterpolator implements SurfaceInterpolator, ImmutableBean, Serializable { public static GridSurfaceInterpolator of(CurveInterpolator xInterpolator, CurveInterpolator yInterpolator) { return new GridSurfaceInterpolator(xInterpolator, FLAT, FLAT, yInterpolator, FLAT, FLAT); } private  GridSurfaceInterpolator(
      CurveInterpolator xInterpolator,
      CurveExtrapolator xExtrapolatorLeft,
      CurveExtrapolator xExtrapolatorRight,
      CurveInterpolator yInterpolator,
      CurveExtrapolator yExtrapolatorLeft,
      CurveExtrapolator yExtrapolatorRight); static GridSurfaceInterpolator of(CurveInterpolator xInterpolator, CurveInterpolator yInterpolator); static GridSurfaceInterpolator of(
      CurveInterpolator xInterpolator,
      CurveExtrapolator xExtrapolator,
      CurveInterpolator yInterpolator,
      CurveExtrapolator yExtrapolator); static GridSurfaceInterpolator of(
      CurveInterpolator xInterpolator,
      CurveExtrapolator xExtrapolatorLeft,
      CurveExtrapolator xExtrapolatorRight,
      CurveInterpolator yInterpolator,
      CurveExtrapolator yExtrapolatorLeft,
      CurveExtrapolator yExtrapolatorRight); @Override BoundSurfaceInterpolator bind(DoubleArray xValues, DoubleArray yValues, DoubleArray zValues); static GridSurfaceInterpolator.Meta meta(); @Override GridSurfaceInterpolator.Meta metaBean(); CurveInterpolator getXInterpolator(); CurveExtrapolator getXExtrapolatorLeft(); CurveExtrapolator getXExtrapolatorRight(); CurveInterpolator getYInterpolator(); CurveExtrapolator getYExtrapolatorLeft(); CurveExtrapolator getYExtrapolatorRight(); @Override boolean equals(Object obj); @Override int hashCode(); @Override String toString();  }### Answer:
@Test public void coverage() { GridSurfaceInterpolator test = GridSurfaceInterpolator.of( LINEAR, FLAT, FLAT, LINEAR, FLAT, FLAT); coverImmutableBean(test); GridSurfaceInterpolator test2 = GridSurfaceInterpolator.of( DOUBLE_QUADRATIC, LOG_LINEAR, LOG_LINEAR, DOUBLE_QUADRATIC, LOG_LINEAR, LOG_LINEAR); coverBeanEquals(test, test2); }
@Test public void test_serialization() { GridSurfaceInterpolator test = GridSurfaceInterpolator.of( LINEAR, FLAT, FLAT, LINEAR, FLAT, FLAT); assertSerialization(test); }