message: Fix open kit editor test by replacing showTextDocument with stub.
diff: @@ -110,7 +110,7 @@ suite('Kits test', () => {
  let path_rescan_kit = testFilePath('rescan_kit.json');
  let sandbox : sinon.SinonSandbox;
  let path_backup : string | undefined;
  - setup( async() => {;
  + setup( async() => {
  sandbox = sinon.sandbox.create();
  let stateMock = sandbox.createStubInstance(state.StateManager);
  sandbox.stub(stateMock, 'activeKitName').get(function () {
  @@ -182,19 +182,39 @@ suite('Kits test', () => {
  });
  });
  - test('KitManager tests opening of kit file', async() => {
  - let stateMock = sinon.createStubInstance(state.StateManager);
  + suite('GUI test', () => {
  + let km : kit.KitManager;
  + let gui_sandbox : sinon.SinonSandbox;
  + setup( async() => {
  + gui_sandbox = sinon.sandbox.create();
  + let stateMock = gui_sandbox.createStubInstance(state.StateManager);
  sinon.stub(stateMock, 'activeKitName').get(function () {
  return null;
  }).set(function() {});
  - const km = new kit.KitManager(stateMock, testFilePath('test_kit.json'));
  +
  + km = new kit.KitManager(stateMock, testFilePath('test_kit.json'));
  + });
  + teardown(async() => {
  + gui_sandbox.restore();
  + });
  +
  + test('KitManager tests opening of kit file', async() => {
  + let text : vscode.TextDocument | undefined;
  + gui_sandbox.stub(vscode.window, "showTextDocument").callsFake(function(textDoc) {
  + text = textDoc;
  + return {document: text};
  + });
  await km.initialize();
  const editor = await km.openKitsEditor();
  + expect(text).to.be.not.undefined;
  + if(text != undefined) {
  const rawKitsFromFile = (await fs.readFile(testFilePath('test_kit.json'), 'utf8'));
  expect(editor.document.getText()).to.be.eq(rawKitsFromFile);
  + } else {}
  }).timeout(5000);
  + });
  test('KitManager tests event on change of active kit', async() => {
  let stateMock = sinon.createStubInstance(state.StateManager);
  