test(web): add unit tests for nestedInstanceOf

Also rename file `utils.ts` to `nestedInstanceOf.ts`.

Test-bot: skip

web/src/engine/src/element-text-stores/createTextStoreForElement.ts

@@ -3,7 +3,7 @@ import { InputElementTextStore } from './inputTextStore.js';
 import { TextAreaElementTextStore } from './textareaTextStore.js';
 import { DesignIFrameElementTextStore } from './designIFrameTextStore.js';
 import { ContentEditableElementTextStore } from './contentEditableTextStore.js';
-import { nestedInstanceOf } from './utils.js';
+import { nestedInstanceOf } from './nestedInstanceOf.js';
 
 export function createTextStoreForElement(e: HTMLElement): AbstractElementTextStore<any> {
   // Complex type scoping is implemented here so that kmwutils.ts is not a dependency for test compilations.

web/src/engine/src/element-text-stores/index.ts

@@ -4,4 +4,4 @@ export { DesignIFrameElementTextStore } from './designIFrameTextStore.js';
 export { InputElementTextStore } from './inputTextStore.js';
 export { AbstractElementTextStore } from './abstractElementTextStore.js';
 export { TextAreaElementTextStore } from './textareaTextStore.js';
-export { nestedInstanceOf } from './utils.js';
+export { nestedInstanceOf } from './nestedInstanceOf.js';

web/src/test/auto/dom/cases/element-text-stores/nestedInstanceOf.tests.ts

@@ -0,0 +1,47 @@
+/*
+ * Keyman is copyright (C) SIL Global. MIT License.
+ */
+import { assert } from 'chai';
+import { nestedInstanceOf } from 'keyman/engine/element-text-stores';
+
+describe('nestedInstanceOf', () => {
+  it('returns false for null input', () => {
+    assert.strictEqual(nestedInstanceOf(null as any, 'HTMLElement'), false);
+  });
+
+  it('returns true for Window object when className is "Window"', () => {
+    assert.strictEqual(nestedInstanceOf(window as any, 'Window'), true);
+  });
+
+  it('returns false for Window object when className is not "Window"', () => {
+    assert.strictEqual(nestedInstanceOf(window as any, 'Document'), false);
+  });
+
+  it('returns true for Document object when className is "Document"', () => {
+    assert.strictEqual(nestedInstanceOf(document as any, 'Document'), true);
+  });
+
+  it('returns false for Document object when className is not "Document"', () => {
+    assert.strictEqual(nestedInstanceOf(document as any, 'HTMLElement'), false);
+  });
+
+  it('returns true for HTMLElement when className is "HTMLElement"', () => {
+    const elem = document.createElement('div');
+    assert.strictEqual(nestedInstanceOf(elem, 'HTMLElement'), true);
+  });
+
+  it('returns false for HTMLElement when className is "HTMLInputElement"', () => {
+    const elem = document.createElement('div');
+    assert.strictEqual(nestedInstanceOf(elem, 'HTMLInputElement'), false);
+  });
+
+  it('returns true for HTMLInputElement when className is "HTMLInputElement"', () => {
+    const input = document.createElement('input');
+    assert.strictEqual(nestedInstanceOf(input, 'HTMLInputElement'), true);
+  });
+
+  it('returns false for unknown className', () => {
+    const elem = document.createElement('div');
+    assert.strictEqual(nestedInstanceOf(elem, 'NonExistentClass'), false);
+  });
+});