Fix regression in BufferedConsole after TS migration

e2e/__tests__/__snapshots__/console.test.ts.snap

@@ -50,6 +50,16 @@ Time:        <<REPLACED>>
 Ran all test suites.
 `;
 
+exports[`does not error out when using winston 1`] = ``;
+
+exports[`does not error out when using winston 2`] = `
+Test Suites: 1 failed, 1 passed, 2 of 1 total
+Tests:       1 passed, 1 total
+Snapshots:   0 total
+Time:        <<REPLACED>>
+Ran all test suites.
+`;
+
 exports[`does not print to console with --silent 1`] = ``;
 
 exports[`does not print to console with --silent 2`] = `PASS __tests__/console.test.js`;

e2e/__tests__/console.test.ts

@@ -59,3 +59,22 @@ test('the jsdom console is the same as the test console', () => {
   expect(wrap(rest)).toMatchSnapshot();
   expect(wrap(summary)).toMatchSnapshot();
 });
+
+test('does not error out when using winston', () => {
+  const {stderr, stdout, status} = runJest('console-winston');
+  const {summary, rest} = extractSummary(stderr);
+
+  expect(wrap(stdout)).toMatchSnapshot();
+  expect(wrap(summary)).toMatchSnapshot();
+  expect(wrap(rest)).toMatchInlineSnapshot(`
+PASS __tests__/console.test.js
+FAIL __tests__/console.test.js
+  ● Test suite failed to run
+
+    TypeError: message.split is not a function
+
+      at buffer.reduce (../../packages/jest-util/build/getConsoleOutput.js:54:8)
+          at Array.reduce (<anonymous>)
+`);
+  expect(status).toBe(0);
+});

e2e/console-winston/__tests__/console.test.js

@@ -0,0 +1,22 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+'use strict';
+
+const winston = require('winston');
+const logger = winston.createLogger({
+  transports: [new winston.transports.Console()],
+});
+
+test('using winston should not fail', () => {
+  logger.log('info', 'Log message from winston');
+
+  logger.info('Info message from winston');
+
+  logger.warn('Warn message from winston');
+
+  logger.error('Error message from winston');
+});

e2e/console-winston/package.json

@@ -0,0 +1,9 @@
+{
+  "jest": {
+    "testEnvironment": "node",
+    "verbose": false
+  },
+  "dependencies": {
+    "winston": "^3.2.1"
+  }
+}