RFC RetailMeNotSandbox#1 - test entry point

The RFC proposes we specify the behavior of a test entry point.

[Fix RetailMeNotSandbox#6]

doc/rfc/1-test-entry-point.md

@@ -0,0 +1,42 @@
+# Summary
+
+## Problem
+
+We want ingredients and pantries to be easy to test. Specifically, it should be
+easy to write both unit and functional tests, easy to run those tests, and easy
+to obtain coverage data.
+
+This RFC proposes the ingredient interface to support these goals.
+
+## Solution Overview
+
+Ingredients may define a test entry point (`test.js`) that runs the ingredient's
+unit and functional tests and reports [TAP](https://testanything.org/) results.
+The test harness can be configured to ensure a Roux server is running before
+executing the test entry point. If it does so, it will provide the URL for that
+server via an environment variable.
+The test harness will be able to execute the test entry points of multiple
+ingredients and report the aggregate results.
+
+# API
+
+## Test entry point
+
+An ingredient MAY define a test entry point by including a file named `test.js`
+in the ingredient root. When invoked, the script must print a [Test Anything
+Protocol (TAP)](https://testanything.org/) test stream to `stdout` before
+exiting. The script MAY run one or more tests when invoked. The result of any
+tests the script runs MUST be printed to the TAP stream. If any test fails, the
+script MUST exit with a non-zero exit code. Otherwise, it MUST exit with an exit
+code of zero.
+
+The test entry point MAY receive configuration via its `process.argv` and
+`process.env` properties.
+
+The test entry point MUST NOT assume a Roux server is running. If a Roux server
+is running, the test entry point WILL receive the root URL for its ingredient as
+an environment variable named `ROUX_INGREDIENT_URL`.
+
+A test entry point MUST NOT assume that it is the only test entry point
+executing. The test harness MAY execute multiple entry points concurrently, so
+access to any shared resources MUST be coordinated via other means.