chore: import upstream snapshot with attribution

tools/challenge-parser/parser/plugins/utils/before-heading.test.js

@@ -0,0 +1,32 @@
+import isArray from 'lodash/isArray';
+import { describe, beforeAll, it, expect } from 'vitest';
+
+import parseFixture from '../../__fixtures__/parse-fixture';
+import getAllBefore from './before-heading';
+
+describe('before-headings', () => {
+  let simpleAst;
+
+  beforeAll(async () => {
+    simpleAst = await parseFixture('simple.md');
+  });
+
+  it('should return an array', () => {
+    expect.assertions(1);
+    const actual = getAllBefore(simpleAst, '--hints--');
+    expect(isArray(actual)).toBe(true);
+  });
+
+  it('should return an empty array if the marker is not present', () => {
+    expect.assertions(2);
+    const actual = getAllBefore(simpleAst, '--not-a-marker--');
+    expect(isArray(actual)).toBe(true);
+    expect(actual.length).toBe(0);
+  });
+
+  it('should include the whole AST before the marker', () => {
+    expect.assertions(1);
+    const actual = getAllBefore(simpleAst, '--hints--');
+    expect(actual).toHaveLength(6);
+  });
+});