Mock throws exception when called twice

[nathanlepori]

Description
Mock throws ExpectationError: Anonymous mock already called once when called twice, even with two preprogrammed returns()/resolves().

To Reproduce

const myMock = sinon.mock()
    .returns('something')
    .returns('something else');

myMock();
myMock();    // Throws 'ExpectationError: Anonymous mock already called once'

Expected behavior
Mock should be able to be reusable, as far as I know. It would be useful in case the system under test calls the function multiple times. I know this works with stubs.

Context

• Library version: 7.0.13
• Environment: Node 12.0.0
• Operating System: Windows 10

[fatso83]

Not sure why anonymous mocks differ from the ones on objects, but adding atLeast() works:

https://runkit.com/fatso83/sinon-workbook/1.0.0

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[mroderick]

This looks like it need a bit more investigation

[rgroothuijsen]

For anonymous mocks, mock delegates most of its behavior to stub (including returns) while maintaining its own minCalls and maxCalls counters that never get updated after calling returns. As noted, these counters can be updated by explicitly calling atLeast and atMost.

[fatso83]

I think this should be closed or changed to update the docs. I guess it's not stated explicitly.

Also, we talked about removing mocks for Sinon 2 and splitting it out into a separate side-project, seeing that none of the maintainers care about them or use them, and seeing we really don't know enough about how they work these days, maybe it's time to revisit that idea 😄