progtest/README.md: Basic test case format documentation

progtest/README.md

@@ -1,5 +1,38 @@
 # Program Testing
+<!--
+  Copyright (C) 2018 R-T Specialty, LLC.
+
+  This file is part of TAME.
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+  Copying and distribution of this file, with or without modification, are
+  permitted in any medium without royalty provided the copyright notice and
+  this notice are preserved.  This file is offered as-is, without warranty
+  of any kind.
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+
 A /program/ is a top-level package (either marked as with `@program="true"`,
 or with a root `rater` node).  This system provides a means of writing and
 running test cases.
 
+
+## Test Case Format
+Test cases must be provided in a YAML file.  Each test case has a
+description (`description`), input data (`data`), and expected results
+(`expect`).
+
+```yaml
+- description: >-
+    Example test case
+  data:
+    state:              [ STATE_AK ]
+    prem_total:         [ 9000 ]
+    effective_date:     12/05/2017
+  expect:
+    premTaxStamping: [ 1234 ]
+    premTaxSurplus:  [ 1010 ]
+```
+
+A file may contain any number of test cases.  All identifiers in `data` and
+`expect` must be valid inputs (params) and outputs (classifications and
+calculations) respectively.  Inputs are passed as-is to the program, and
+outputs are recursively (deeply) compared.