Add unittest docs

docs/index.md

@@ -11,10 +11,12 @@ Dnscontrol is a platform for seamlessly managing your dns configuration across a
 
 ## [Language Reference]({{site.github.url}}/js): Description of the DNSControl language (DSL).
 
-## [Examples]({{site.github.url}}/examples): DSL examples.
+## [Examples]({{site.github.url}}/examples): The DNSControl language by example.
 
 ## [Migrating]({{site.github.url}}/migrating): Migrating zones to DNSControl.
 
+## [Testing]({{site.github.url}}/unittests): Unit Testing DNS Data.
+
 ## [github](https://github.com/StackExchange/dnscontrol): Get the source!
 
 

docs/unittests.md

@@ -0,0 +1,33 @@
+# Unit Testing DNS Data
+
+## Testing
+
+DNSControl performs a number of tests during the validation stage.
+You can find them in `pkg/normalize/validate.go`.
+
+
+## External tests
+
+Tests specific to your environment may be added as external tests.
+Output the intermediate representation as a JSON file and perform
+tests on this data.
+
+Output the intermediate representation:
+
+    dnscontrol -debugjson foo.json print
+
+Here is a sample test written in `bash` using the [jq](https://stedolan.github.io/jq/) command.  This fails if the number of MX records in the `stackex.com` domain is not exactly 5:
+
+    COUNTMX=$(jq --raw-output <foo.json '.domains[] | select(.name == "stackex.com") | .records[] | select(.type == "MX") | .target' | wc -l)
+    echo COUNT=:"$COUNTMX":
+    if [[ "$COUNTMX" -eq "5" ]]; then
+      echo GOOD
+    else
+      echo BAD
+    fi
+
+
+## Future directions
+
+Manipulting JSON data is difficult. If you implement ways to make it easier, we'd
+gladly accept contributions.