test(catchError): add failing test

spec/operators/catch-spec.ts

@@ -1,5 +1,5 @@
 import { expect } from 'chai';
-import { of, throwError, EMPTY, from } from 'rxjs';
+import { concat, Observable, of, throwError, EMPTY, from } from 'rxjs';
 import { catchError, map, mergeMap } from 'rxjs/operators';
 import { TestScheduler } from 'rxjs/testing';
 import * as sinon from 'sinon';
@@ -285,6 +285,21 @@ describe('catchError operator', () => {
  });
  });
 
+ it('should catch errors throw from within the constructor', () => {
+ // See https://github.com/ReactiveX/rxjs/issues/3740
+ const source = concat(
+ new Observable<string>(o => {
+ o.next('a');
+ throw 'kaboom';
+ }).pipe(
+ catchError(_ => of('b'))
+ ),
+ of('c')
+ );
+ const expected = '(abc|)';
+ expectObservable(source).toBe(expected);
+ });
+
  context('fromPromise', () => {
  type SetTimeout = (callback: (...args: any[]) => void, ms: number, ...args: any[]) => NodeJS.Timer;