add README

pkg/js/README-parse_tests.md

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+
+# Parse Tests
+
+The `parse_tests` directory contains test cases for `js_test.go`.  `js_test.go`
+scans for files named `DDD-*.js` where `DDD` is a three-digit number.
+
+* `parse_tests/001-basic.js`  -- The dnsconfig.js file.
+* `parse_tests/001-basic.json` -- The EXPECTED output of "print-ir" for the `.js` file.
+* `parse_tests/001-basic.json.ACTUAL` -- The ACTUAL output of "print-ir" for the `.js` file (not saved in git)
+* `parse_tests/001-basic/foo.com.zone` -- Zonefiles from the domains mentioned in dnsconfig.js
+
+NOTE: The zonefiles are only generated if a matching `DDD-name/DOMAINNAME.zone` file exists.
+
+Any files committed to Git should be in standard format.
+
+# Fix formatting
+
+Fix the `.js` formatting:
+
+```
+cd parse_tests
+for i in *.js ; do echo ========== $i ; dnscontrol fmt -i $i -o $i ; done
+```
+
+Fix the `.json` formatting:
+
+```
+cd parse_tests
+fmtjson *.json *.json.ACTUAL
+```
+
+# Copy actuals to expected.
+
+Back-port the ACTUAL results to the expected results:
+
+(This is dangerous.  Carefully inspect the resulting PR.)
+
+```
+cd parse_tests
+fmtjson *.json *.json.ACTUAL
+for i in *.ACTUAL ; do f=$(basename $i .ACTUAL) ; cp $i $f ; done
+```