Add .env.test back for integration tests

Oops, removing .env.test makes integration tests (that need the AWS_*
env vars set) fail. Let's add it back but be explicit about injecting
ENV in unit tests.

Author: leesharma

.env.test

@@ -0,0 +1,4 @@
+# For integration tests
+AWS_ACCESS_KEY="aws_access_key"
+AWS_SECRET_KEY="aws_secret_key"
+AWS_ASSOCIATES_TAG="aws_associates_tag"