Add Tests for SocketModeReceiver

[stevengill]

Description

Need to write some tests for SocketModeReceiver after figuring out an appropriate test harness.

What type of issue is this? (place an x in one of the [ ])

• bug
• enhancement (feature request)
• question
• documentation related
• example code related
• testing related
• discussion

Requirements (place an x in each of the [ ])

• I've read and understood the Contributing guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.
• I've searched for any related issues and avoided creating a duplicate issue.

---

Bug Report

Filling out the following details about bugs will help us solve your issue sooner.

Reproducible in:

package version:

node version:

OS version(s):

Steps to reproduce:

Expected result:

What you expected to happen

Actual result:

What actually happened

Attachments:

Logs, screenshots, screencast, sample project, funny gif, etc.

[seratch]

Probably, I will start working on this soon. If anyone in the community has thoughts or ideas about this, sharing them with us would be greatly appreciated!