Make Jest tests fail if tests emit any console messages

jestFailOnConsoleMessages.js

// Fail the test if it prints ANYTHING to the console!
//
// Warning & log messages in test output are an anti-pattern. Also, testing
// for console messages is the only way to check for PropTypes failures
// (because all PropTypes does is print a console warning)
const realConsole = global.console;

// TODO: It's possible that some of the functions under global.console may
// have legitimate uses during test runs. If so, we'll need to be more picky.
global.console = Object.keys(realConsole).reduce(
  (acc, consoleFunctionName) => ({
    ...acc,
    [consoleFunctionName]: (...args) => {
      realConsole[consoleFunctionName](args);
      // expect().alwaysFail() is a custom Jest matcher that automatically fails.
      // It's at the end of this file.
      expect(args).alwaysFail(
        `Test invoked "console.${consoleFunctionName}()"! Tests should NOT emit messages to the console. >:(`
      );
    },
  }),
  {}
);

// A custom Jest matcher to force a failure and print an informative message
// about it.
expect.extend({
  alwaysFail(received, failureMessage) {
    return {
      pass: false,
      message: () =>
        failureMessage +
        (received ? '\n\nDetails:\n' + this.utils.printReceived(received) : ''),
    };
  },
});