message: Fix WebGL test to support null context
diff: @@ -9,11 +9,11 @@ let context = unknownContext;
  *
  * @static
  * @private
  - * @returns {webGL-context} a gl context to test with
  + * @returns {WebGLRenderingContext} a gl context to test with
  */
  export function getTestContext()
  {
  - if (context === unknownContext || context.isContextLost())
  + if (context === unknownContext || (context && context.isContextLost()))
  {
  const canvas = document.createElement('canvas');
  