test: improve test coverage for DataProviderController

packages/component-base/test/data-provider-controller-cache.test.js

@@ -1,6 +1,8 @@
 import { expect } from '@esm-bundle/chai';
 import { Cache } from '../src/data-provider-controller/cache.js';
 
+const PLACEHOLDER = Symbol('PLACEHOLDER');
+
 describe('DataProviderController - Cache', () => {
  let cache;
  let expandedItems = [];
@@ -51,23 +53,42 @@ describe('DataProviderController - Cache', () => {
  });
  });
 
+ describe('with placeholder', () => {
+ beforeEach(() => {
+ cache = new Cache({ isExpanded, placeholder: PLACEHOLDER }, 2, 20);
+ });
+
+ it('should have items filled with placeholders', () => {
+ expect(cache.items).to.have.lengthOf(20);
+ expect(cache.items.every((item) => item === PLACEHOLDER)).to.be.true;
+ });
+ });
+
  describe('setPage', () => {
  beforeEach(() => {
- cache = new Cache({ isExpanded }, 50, 500);
+ cache = new Cache({ isExpanded }, 2, 20);
  });
 
- it('should insert the items at the correct position for page 0', () => {
+ it('should insert items at the correct position for page 0', () => {
  cache.setPage(0, ['Item 0', 'Item 1']);
  expect(cache.items).to.have.lengthOf(2);
  expect(cache.items[0]).to.equal('Item 0');
  expect(cache.items[1]).to.equal('Item 1');
  });
 
- it('should insert the items at the correct position for page 1', () => {
- cache.setPage(1, ['Item 0', 'Item 1']);
- expect(cache.items).to.have.lengthOf(52);
- expect(cache.items[50]).to.equal('Item 0');
- expect(cache.items[51]).to.equal('Item 1');
+ it('should insert items at the correct position for page 1', () => {
+ cache.setPage(1, ['Item 2', 'Item 3']);
+ expect(cache.items).to.have.lengthOf(4);
+ expect(cache.items[2]).to.equal('Item 2');
+ expect(cache.items[3]).to.equal('Item 3');
+ });
+
+ it('should discard items that exceed the size bounds', () => {
+ cache.setPage(9, ['Item 18', 'Item 19', 'Item 20']);
+ expect(cache.items).to.have.lengthOf(20);
+ expect(cache.items[18]).to.equal('Item 18');
+ expect(cache.items[19]).to.equal('Item 19');
+ expect(cache.items[20]).to.be.undefined;
  });
  });
 
@@ -197,6 +218,38 @@ describe('DataProviderController - Cache', () => {
  });
  });
 
+ describe('size', () => {
+ beforeEach(() => {
+ cache = new Cache({ isExpanded }, 2, 20);
+ });
+
+ it('should remove exceeding pending requests when decreasing size', () => {
+ cache.pendingRequests[8] = (_items, _size) => {};
+ cache.pendingRequests[9] = (_items, _size) => {};
+ cache.size = 18;
+ expect(cache.pendingRequests[8]).to.be.not.undefined;
+ expect(cache.pendingRequests[9]).to.be.undefined;
+ });
+ });
+
+ describe('size with placeholder', () => {
+ beforeEach(() => {
+ cache = new Cache({ isExpanded, placeholder: PLACEHOLDER }, 2, 20);
+ });
+
+ it('should add more placeholders when increasing size', () => {
+ cache.size = 22;
+ expect(cache.items).to.have.lengthOf(22);
+ expect(cache.items.every((item) => item === PLACEHOLDER)).to.be.true;
+ });
+
+ it('should remove exceeding placeholders when decreasing size', () => {
+ cache.size = 18;
+ expect(cache.items).to.have.lengthOf(18);
+ expect(cache.items.every((item) => item === PLACEHOLDER)).to.be.true;
+ });
+ });
+
  describe('flatSize', () => {
  beforeEach(() => {
  cache = new Cache({ isExpanded }, 50, 500);

packages/component-base/test/data-provider-controller-placeholder.test.js

@@ -0,0 +1,85 @@
+import { expect } from '@esm-bundle/chai';
+import sinon from 'sinon';
+import '@vaadin/testing-helpers';
+import { DataProviderController } from '../src/data-provider-controller/data-provider-controller.js';
+import { createDataProvider } from './data-provider-controller-helpers.js';
+
+class Placeholder {}
+
+class CustomPlaceholder extends Placeholder {}
+
+describe('DataProviderController - placeholder', () => {
+ let host, controller, placeholder, dataProviderSpy;
+
+ describe('default', () => {
+ beforeEach(() => {
+ host = document.createElement('div');
+
+ placeholder = new Placeholder();
+
+ controller = new DataProviderController(host, {
+ size: 10,
+ pageSize: 2,
+ placeholder,
+ dataProvider: createDataProvider({ size: 10, async: true }),
+ });
+
+ dataProviderSpy = sinon.spy(controller, 'dataProvider');
+ });
+
+ it('should have placeholder', () => {
+ expect(controller.placeholder).to.equal(placeholder);
+ });
+
+ it('should have rootCache items filled with placeholders', () => {
+ expect(controller.rootCache.items).to.have.lengthOf(10);
+ expect(controller.rootCache.items.every((item) => item === placeholder)).to.be.true;
+ });
+
+ it('should request data when encountering the controller placeholder instance', () => {
+ controller.ensureFlatIndexLoaded(0);
+ expect(dataProviderSpy).to.have.callCount(1);
+
+ controller.ensureFlatIndexLoaded(1);
+ expect(dataProviderSpy).to.have.callCount(1);
+
+ controller.ensureFlatIndexLoaded(2);
+ expect(dataProviderSpy).to.have.callCount(2);
+
+ controller.ensureFlatIndexLoaded(3);
+ expect(dataProviderSpy).to.have.callCount(2);
+ });
+
+ it('should not request data when encountering a different placeholder instance', () => {
+ controller.rootCache.items[0] = new CustomPlaceholder();
+ controller.ensureFlatIndexLoaded(0);
+ expect(dataProviderSpy).to.have.callCount(0);
+ });
+ });
+
+ describe('custom equality function', () => {
+ beforeEach(() => {
+ host = document.createElement('div');
+
+ controller = new DataProviderController(host, {
+ size: 10,
+ pageSize: 2,
+ placeholder: new Placeholder(),
+ isPlaceholder: (item) => item instanceof Placeholder,
+ dataProvider: createDataProvider({ size: 10, async: true }),
+ });
+
+ dataProviderSpy = sinon.spy(controller, 'dataProvider');
+ });
+
+ it('should request data when encountering any placeholder instance', () => {
+ controller.rootCache.items[0] = new CustomPlaceholder();
+
+ controller.ensureFlatIndexLoaded(0);
+ expect(dataProviderSpy).to.have.callCount(1);
+
+ controller.ensureFlatIndexLoaded(2);
+ expect(dataProviderSpy).to.have.callCount(2);
+ });
+ });
+});

packages/component-base/test/data-provider-controller.test.js

@@ -5,6 +5,8 @@ import { Cache } from '../src/data-provider-controller/cache.js';
 import { DataProviderController } from '../src/data-provider-controller/data-provider-controller.js';
 import { createDataProvider } from './data-provider-controller-helpers.js';
 
+const PLACEHOLDER = Symbol('PLACEHOLDER');
+
 describe('DataProviderController', () => {
  let host, controller;
 
@@ -47,10 +49,22 @@ describe('DataProviderController', () => {
  expect(controller.flatSize).to.equal(0);
  });
 
+ it('should not have placeholder', () => {
+ expect(controller.placeholder).to.be.undefined;
+ });
+
+ it('should not have isPlaceholder', () => {
+ expect(controller.isPlaceholder).to.be.undefined;
+ });
+
  it('should have rootCache', () => {
  expect(controller.rootCache).to.be.instanceOf(Cache);
  });
 
+ it('should have empty rootCache items', () => {
+ expect(controller.rootCache.items).to.have.lengthOf(0);
+ });
+
  it('should not have rootCache size', () => {
  expect(controller.rootCache.size).to.be.undefined;
  });
@@ -85,6 +99,10 @@ describe('DataProviderController', () => {
  it('should have rootCache size', () => {
  expect(controller.rootCache.size).to.equal(500);
  });
+
+ it('should have empty rootCache items', () => {
+ expect(controller.rootCache.items).to.have.lengthOf(0);
+ });
  });
 
  describe('with dataProviderParams', () => {