[keystore] Fix openHandle in Jest tests (#96671) (#96973)

```
[2021-04-07T00:19:27Z] Jest did not exit one second after the test run has completed.
[2021-04-07T00:19:27Z]
[2021-04-07T00:19:27Z] This usually means that there are asynchronous operations that weren't stopped in your tests. Consider running Jest with `--detectOpenHandles` to troubleshoot this issue.
```

Signed-off-by: Tyler Smalley <tyler.smalley@elastic.co>

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

Co-authored-by: Tyler Smalley <tyler.smalley@elastic.co>

src/cli_keystore/utils/prompt.js

@@ -75,6 +75,7 @@ export function question(question, options = {}) {
     });
 
     rl.question(questionPrompt, (value) => {
+      rl.close();
       resolve(value);
     });
   });

src/cli_keystore/utils/prompt.test.js

@@ -6,14 +6,11 @@
  * Side Public License, v 1.
  */
 
-import sinon from 'sinon';
 import { PassThrough } from 'stream';
 
 import { confirm, question } from './prompt';
 
 describe('prompt', () => {
-  const sandbox = sinon.createSandbox();
-
   let input;
   let output;
 
@@ -23,30 +20,27 @@ describe('prompt', () => {
   });
 
   afterEach(() => {
-    sandbox.restore();
+    input.end();
+    output.end();
   });
 
   describe('confirm', () => {
     it('prompts for question', async () => {
-      const onData = sandbox.stub(output, 'write');
-
-      confirm('my question', { output });
+      const write = jest.spyOn(output, 'write');
 
-      sinon.assert.calledOnce(onData);
+      process.nextTick(() => input.write('Y\n'));
+      await confirm('my question', { input, output });
 
-      const { args } = onData.getCall(0);
-      expect(args[0]).toEqual('my question [y/N] ');
+      expect(write).toHaveBeenCalledWith('my question [y/N] ');
     });
 
     it('prompts for question with default true', async () => {
-      const onData = sandbox.stub(output, 'write');
-
-      confirm('my question', { output, default: true });
+      const write = jest.spyOn(output, 'write');
 
-      sinon.assert.calledOnce(onData);
+      process.nextTick(() => input.write('Y\n'));
+      await confirm('my question', { input, output, default: true });
 
-      const { args } = onData.getCall(0);
-      expect(args[0]).toEqual('my question [Y/n] ');
+      expect(write).toHaveBeenCalledWith('my question [Y/n] ');
     });
 
     it('defaults to false', async () => {
@@ -87,14 +81,12 @@ describe('prompt', () => {
 
   describe('question', () => {
     it('prompts for question', async () => {
-      const onData = sandbox.stub(output, 'write');
-
-      question('my question', { output });
+      const write = jest.spyOn(output, 'write');
 
-      sinon.assert.calledOnce(onData);
+      process.nextTick(() => input.write('my answer\n'));
+      await question('my question', { input, output });
 
-      const { args } = onData.getCall(0);
-      expect(args[0]).toEqual('my question: ');
+      expect(write).toHaveBeenCalledWith('my question: ');
     });
 
     it('can be answered', async () => {