message: Add checks for warnings
diff: @@ -66,6 +66,8 @@ const mkdocsYmlWithComments = fs.readFileSync(
  resolvePath(__filename, '../__fixtures__/mkdocs_with_comments.yml'),
  );
  const mockLogger = getVoidLogger();
  +const warn = jest.spyOn(mockLogger, 'warn');
  +
  const rootDir = os.platform() === 'win32' ? 'C:\\rootDir' : '/rootDir';
  const scmIntegrations = ScmIntegrations.fromConfig(new ConfigReader({}));
  @@ -288,6 +290,9 @@ describe('helpers', () => {
  });
  describe('patchIndexPreBuild', () => {
  + afterEach(() => {
  + warn.mockClear();
  + });
  it('should have no effect if docs/index.md exists', async () => {
  mockFs({
  '/docs/index.md': 'index.md content',
  @@ -299,6 +304,7 @@ describe('helpers', () => {
  expect(fs.readFileSync('/docs/index.md', 'utf-8')).toEqual(
  'index.md content',
  );
  + expect(warn).not.toHaveBeenCalledWith();
  mockFs.restore();
  });
  @@ -313,6 +319,7 @@ describe('helpers', () => {
  expect(fs.readFileSync('/docs/index.md', 'utf-8')).toEqual(
  'docs/README.md content',
  );
  + expect(warn.mock.calls).toEqual([['docs/index.md not found.']]);
  mockFs.restore();
  });
  @@ -326,6 +333,11 @@ describe('helpers', () => {
  expect(fs.readFileSync('/docs/index.md', 'utf-8')).toEqual(
  'main README.md content',
  );
  + expect(warn.mock.calls).toEqual([
  + ['docs/index.md not found.'],
  + ['docs/README.md not found.'],
  + ['docs/readme.md not found.'],
  + ]);
  mockFs.restore();
  });
  @@ -335,6 +347,16 @@ describe('helpers', () => {
  await patchIndexPreBuild({ inputDir: '/', logger: mockLogger });
  expect(() => fs.readFileSync('/docs/index.md', 'utf-8')).toThrow();
  + expect(warn.mock.calls).toEqual([
  + ['docs/index.md not found.'],
  + ['docs/README.md not found.'],
  + ['docs/readme.md not found.'],
  + ['README.md not found.'],
  + ['readme.md not found.'],
  + [
  + "Could not find any techdocs' index file. Please make sure at least one of /docs/index.md /docs/README.md /docs/readme.md /README.md /readme.md exists.",
  + ],
  + ]);
  mockFs.restore();
  });
  });
  @@ -459,7 +481,7 @@ describe('helpers', () => {
  it('should return true on when a valid docs_dir is present', async () => {
  await expect(
  validateMkdocsYaml(inputDir, mkdocsYmlWithValidDocDir.toString()),
  - ).resolves.toBeUndefined();
  + ).resolves.toBe('docs/');
  });
  it('should return false on absolute doc_dir path', async () => {
  