import { Resource } from "../../Source/Cesium.js";
import { DiscardEmptyTileImagePolicy } from "../../Source/Cesium.js";
import pollToPromise from "../pollToPromise.js";
import { when } from "../../Source/Cesium.js";

describe("Scene/DiscardEmptyTileImagePolicy", function () {
  afterEach(function () {
    Resource._Implementations.createImage =
      Resource._DefaultImplementations.createImage;
    Resource._Implementations.loadWithXhr =
      Resource._DefaultImplementations.loadWithXhr;
  });

  describe("shouldDiscardImage", function () {
    it("does not discard a non-empty image", function () {
      var promises = [];
      promises.push(Resource.fetchImage("Data/Images/Green4x4.png"));

      var policy = new DiscardEmptyTileImagePolicy();

      promises.push(
        pollToPromise(function () {
          return policy.isReady();
        })
      );

      return when.all(promises, function (results) {
        var greenImage = results[0];

        expect(policy.shouldDiscardImage(greenImage)).toEqual(false);
      });
    });

    it("discards an empty image", function () {
      var promises = [];
      promises.push(when.resolve(DiscardEmptyTileImagePolicy.EMPTY_IMAGE));

      var policy = new DiscardEmptyTileImagePolicy();

      promises.push(
        pollToPromise(function () {
          return policy.isReady();
        })
      );

      return when.all(promises, function (results) {
        var emptyImage = results[0];

        expect(policy.shouldDiscardImage(emptyImage)).toEqual(true);
      });
    });
  });
});