Updating gencode.md docs (#440)

bin/loop_sequences

@@ -51,7 +51,10 @@ validator/bin/build
 JARFILE=validator/build/libs/validator-1.0-SNAPSHOT-all.jar
 JAVA_CMD="java -cp $JARFILE com.google.daq.mqtt.sequencer.SequenceTestRunner"
 
-rm -rf $site_model/out/devices/$device_id
+if [[ $test_names == . ]]; then
+    # Only clear out tests if running complete battery, else keep to allow incremental upates.
+    rm -rf $site_model/out/devices/$device_id
+fi
 
 test_srces=`cd validator/src/main/java/com/google/daq/mqtt/sequencer/sequences; ls *.java`
 echo Processing test sources $test_srces

docs/specs/sequences/generated.md

@@ -5,7 +5,26 @@
 These are the exact sequences being checked by the sequence tool. They are programaticaly generated
 so maybe a bit cryptic, but they accurately represent the specific steps required for each test.
 
-<!-- To regenerate the contents of this file below, use bin/test_sequencer and bin/gencode_seq -->
+<!--
+
+To regenerate the contents of this file below, first generate a message trace sequence and then run bin/gencode_seq
+
+* Running "bin/test_sequencer target-gcp-project" will run through the complete battery of test sequences
+  against the AHU-1 device to create the requisite trace files. This takes about 4 min for a complete test run.
+
+* Then run "bin/gencode_seq" which consumes the generated trace files and creates "generated.md" (this file)
+  with the output. The diff (using git, usually) should then reflect the changes against the committed version.
+
+Some caveats:
+
+* Flaky tests are annoying. Sometimes something goes wrong and one entire test will be borked. Easist thing
+  is to just re-run the sequence tests until it's clean, but that's not always the fastest.
+
+* The gencode part requires a complete test run to work properly, but you can run individual test runs
+  as needed, e.g. "bin/sequencer sites/udmi_site/model target-gcp-project AHU-1 21632 system_last_update"
+  (you will need to run an instance of pubber separately).
+
+-->
 
 <!-- START GENERATED, do not edit anything after this line! -->
 * [broken_config](#broken_config): Check that the device correctly handles a broken (non-json) config message.