test: standardized jest unit testing (#10047)

packages/core/data/observable-array/index.spec.ts

@@ -0,0 +1,70 @@
+import { ObservableArray } from '.';
+
+describe('ObservableArray', () => {
+	describe('splice', () => {
+		it('removes an item', () => {
+			const _array = new ObservableArray();
+
+			_array.push(1);
+			_array.push(2);
+
+			_array.splice(0, 1);
+
+			expect(_array.getItem(0)).toBe(2);
+		});
+
+		it('replaces an item', () => {
+			const _array = new ObservableArray();
+
+			_array.push(1);
+			_array.push(2);
+
+			_array.splice(0, 1, 3);
+
+			expect(_array.getItem(0)).toBe(3);
+		});
+
+		it('empties on start zero and no delete count', () => {
+			const _array = new ObservableArray();
+
+			_array.push(1);
+
+			_array.splice(0);
+			expect(_array.length).toBe(0);
+		});
+
+		it('empties on length set to zero', () => {
+			const _array = new ObservableArray();
+
+			_array.push(1);
+			_array.push(2);
+
+			_array.length = 0;
+			expect(_array.length).toBe(0);
+		});
+	});
+
+	describe('findIndex', () => {
+		it('finds an item', () => {
+			const _array = new ObservableArray();
+
+			_array.push(1);
+			_array.push(2);
+
+			const index = _array.findIndex((i) => i === 2);
+
+			expect(index).toBe(1);
+		});
+
+		it('does not find item', () => {
+			const _array = new ObservableArray();
+
+			_array.push(1);
+			_array.push(2);
+
+			const index = _array.findIndex((i) => i === 3);
+
+			expect(index).toBe(-1);
+		});
+	});
+});