test: add tests for applyProps

src/helpers/appendChild.js

@@ -6,7 +6,7 @@ import { log } from './log.js';
  * Adds elements to our application.
  *
  * @param {Instance} parentInstance
- * @param {Instance} childInstance
+ * @param {Instance | null} childInstance
  */
 export function appendChild(parentInstance, childInstance)
 {

test/unit/helpers/applyProps.test.js

@@ -0,0 +1,52 @@
+import { Container } from 'pixi.js';
+import {
+    describe,
+    expect,
+    it,
+} from 'vitest';
+import { applyProps } from '../../../src/helpers/applyProps.js';
+import { prepareInstance } from '../../../src/helpers/prepareInstance.js';
+
+describe('applyProps', () =>
+{
+    describe('when given instance props', () =>
+    {
+        it('updates the target instance', () =>
+        {
+            expect(applyProps).to.be.a('function');
+            const instance = prepareInstance(new Container());
+
+            expect(instance.x).to.equal(0);
+
+            const result = applyProps(instance, { x: 100 });
+
+            expect(result).to.equal(instance);
+            expect(instance.x).to.equal(100);
+        });
+    });
+
+    describe('when given a diff set', () =>
+    {
+        it('updates the target instance', () =>
+        {
+            expect(applyProps).to.be.a('function');
+            const instance = prepareInstance(new Container());
+
+            expect(instance.x).to.equal(0);
+
+            const result = applyProps(instance, {
+                changes: [
+                    [
+                        'x',
+                        100,
+                        false,
+                        [],
+                    ],
+                ],
+            });
+
+            expect(result).to.equal(instance);
+            expect(instance.x).to.equal(100);
+        });
+    });
+});