Added testing.md to explain how to write a test (#10)

.github/PULL_REQUEST_TEMPLATE.md

@@ -2,6 +2,6 @@
 Describe the contents of the PR
 
 #### How do we test this?
-Provide commands/steps to test this PR.
+Have you followed the TESTING.md doc? If not, please provide commands/steps to test this PR.
 
 cc: @redhat-cop/day-in-the-life

TESTING.md

@@ -0,0 +1,10 @@
+# testing
+This repo uses as a combination of [bats](https://github.com/bats-core/bats-core) and [conftest](https://github.com/open-policy-agent/conftest)
+to validate the rego policies.
+
+## How do i write a test?
+Each test is expected to have a directory under [_test](_test) which contains the test input data; typically a yaml file 
+containing a OCP Template or k8s List.
+
+The tests are executed by [_test/tests.bats](_test/tests.bats). The test should validate each expected bats output and always
+end with the expected success line.