TO API test TestCDNs fails: Expected only one cdn response

[zrhoffman]

I'm submitting a ...

• bug report

Traffic Control components affected ...

• Traffic Ops

Current behavior:

TestCDNs fails for API v4:

INFO: traffic_ops_test.go:71: 2021-06-17T00:00:33.129707062Z: Using Config values:
                           TO Config File:       ../conf/traffic-ops-test.conf
                           TO Fixtures:          tc-fixtures.json
                           TO URL:               https://localhost:6443
                           TO Session Timeout In Secs:  60
                           DB Server:            localhost
                           DB User:              traffic_ops
                           DB Name:              traffic_ops
                           DB Ssl:               false
               UseIMS:               true
=== RUN   TestCDNs
    cdns_test.go:386: Expected only one cdn response {[] {[]}}
--- FAIL: TestCDNs (1.62s)
FAIL
FAIL    github.com/apache/trafficcontrol/traffic_ops/testing/api/v4     2.130s
FAIL

Expected behavior:

TestCDNs should pass.

Minimal reproduction of the problem with instructions:

go test ./v4 -cfg=../conf/traffic-ops-test.conf -test.v -test.run '^TestCDNs$'

[ocket8888]

The Fatal call is hiding another error that occurs later in the test - checking for a 400 response code when TO returns 404 when attempting to delete a CDN that doesn't exist