Fix DOMTextScanner entering initial div on backwards seeks (#1071)

* Fix dom-text-scanner entering initial div on reverse seeks

* Add new case

* Add launch.json

* Cleanup launch.json

1 files changed, 80 insertions, 0 deletions

diff --git a/test/text-source-range.test.js b/test/text-source-range.test.js
new file mode 100644
index 00000000..d92198c3
--- /dev/null
+++ b/test/text-source-range.test.js
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2024  Yomitan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import {fail} from 'node:assert';
+import {fileURLToPath} from 'node:url';
+import path from 'path';
+import {afterAll, describe, expect, test} from 'vitest';
+import {TextSourceRange} from '../ext/js/dom/text-source-range.js';
+import {setupDomTest} from './fixtures/dom-test.js';
+
+
+const dirname = path.dirname(fileURLToPath(import.meta.url));
+const textSourceRangeTestEnv = await setupDomTest(path.join(dirname, 'data/html/text-source-range.html'));
+
+
+describe('TextSourceRange', () => {
+    const {window, teardown} = textSourceRangeTestEnv;
+    afterAll(() => teardown(global));
+
+    test('lazy', () => {
+        const {document} = window;
+        const testElement /** @type {NodeListOf<HTMLElement>} */ = document.getElementById('text-source-range-lazy');
+        if (testElement === null) {
+            fail('test element not found');
+        }
+
+        const range = new Range();
+        range.selectNodeContents(testElement);
+
+        const source = TextSourceRange.createLazy(range);
+        const startLength = source.setStartOffset(200, false);
+        const endLength = source.setEndOffset(200, true, false);
+
+        const text = source.text();
+        const textLength = text.length;
+
+        expect(startLength).toBeLessThanOrEqual(textLength);
+        expect(endLength).toBeLessThan(textLength);
+        const count = (text.match(/人/g) || []).length;
+        expect(count).toEqual(1);
+    });
+
+    test('standard', () => {
+        const {document} = window;
+        const testElement /** @type {NodeListOf<HTMLElement>} */ = document.getElementById('text-source-range');
+        if (testElement === null) {
+            fail('test element not found');
+        }
+
+        const range = new Range();
+
+        range.selectNodeContents(testElement);
+
+        const source = TextSourceRange.create(range);
+        const startLength = source.setStartOffset(15, false);
+        const endLength = source.setEndOffset(15, true, false);
+
+        const text = source.text();
+        const textLength = text.length;
+
+        expect(startLength).toBeLessThan(textLength);
+        expect(endLength).toBeLessThan(textLength);
+        const count = (text.match(/山/g) || []).length;
+        expect(count).toEqual(1);
+    });
+});