DOC: NEW: How to test a branch (#3264)

Co-authored-by: Jeffrey Cafferata <[email protected]>

documentation/SUMMARY.md

@@ -186,6 +186,7 @@
 * [Writing new DNS providers](writing-providers.md)
 * [Creating new DNS Resource Types (rtypes)](adding-new-rtypes.md)
 * [Integration Tests](integration-tests.md)
+* [Test a branch](test-a-branch.md)
 * [Unit Testing DNS Data](unittests.md)
 * [Bug Triage Process](bug-triage.md)
 * [Bring-Your-Own-Secrets for automated testing](byo-secrets.md)

documentation/test-a-branch.md

@@ -0,0 +1,65 @@
+### Test A Branch
+
+Instructions for testing DNSControl at a particular PR or branch.
+
+## Using Docker
+
+Using Docker assures you're using the latest version of Go and doesn't require you to install anything on your machine, other than Docker!
+
+Assumptions:
+* `/THE/PATH` -- Change this to the full path to where your dnsconfig.js and other files are located.
+* `INSERT_BRANCH_HERE` -- The branch you want to test.  The branch associated with a PR is listed on [https://github.com/StackExchange/dnscontrol/branches](https://github.com/StackExchange/dnscontrol/branches).
+
+```
+docker run -it -v /THE/PATH:/dns golang
+git clone https://github.com/StackExchange/dnscontrol.git
+cd dnscontrol
+git checkout INSERT_BRANCH_HERE
+go install
+
+cd /dns
+dnscontrol preview
+```
+
+If you want to run the integration tests, follow the
+[Integration Tests](https://docs.dnscontrol.org/developer-info/integration-tests) document
+as usual. The directory to be in is `/go/dnscontrol/integrationTest`.
+
+```
+cd /go/dnscontrol/integrationTest
+go test -v -verbose -provider INSERT_PROVIDER_NAME -start 1 -end 3
+```
+
+Change `INSERT_PROVIDER_NAME` to the name of your provider (BIND, ROUTE53, GCLOUD, etc.)
+
+
+## Not using Docker
+
+Assumptions:
+* `/THE/PATH` -- Change this to the full path to where your dnsconfig.js and other files are located.
+* `INSERT_BRANCH_HERE` -- The branch you want to test.  The branch associated with a PR is listed on [https://github.com/StackExchange/dnscontrol/branches](https://github.com/StackExchange/dnscontrol/branches).
+
+Step 1: Install Go
+
+[https://go.dev/dl/](https://go.dev/dl/)
+
+Step 2: Check out the software
+
+```
+git clone https://github.com/StackExchange/dnscontrol.git
+cd dnscontrol
+git checkout INSERT_BRANCH_HERE
+go install
+
+cd /THE/PATH
+dnscontrol preview
+```
+
+Step 3: Clean up
+
+`go install` put the `dnscontrol` program in your `$HOME/bin` directory. You probably want to remove it.
+
+```
+$ rm -i $HOME/bin/dnscontrol
+```
+