Bug 1000719 - Add tracing on logging experiment rejections and telemetry tests. r=bsmedberg

browser/experiments/Experiments.jsm

@@ -1123,7 +1123,9 @@ Experiments.Experiments.prototype = {
           let desc = TELEMETRY_LOG.ACTIVATION;
           let data = [TELEMETRY_LOG.ACTIVATION.REJECTED, id];
           data = data.concat(reason);
-          TelemetryLog.log(TELEMETRY_LOG.ACTIVATION_KEY, data);
+          const key = TELEMETRY_LOG.ACTIVATION_KEY;
+          TelemetryLog.log(key, data);
+          this._log.trace("evaluateExperiments() - added " + key + " to TelemetryLog: " + JSON.stringify(data));
         }
 
         if (!applicable) {

browser/experiments/test/xpcshell/test_telemetry.js

@@ -175,6 +175,7 @@ add_task(function* test_telemetryBasics() {
 
   expectedLogLength += 2;
   let log = TelemetryPing.getPayload().log;
+  do_print("Telemetry log: " + JSON.stringify(log));
   Assert.equal(log.length, expectedLogLength, "Telemetry log should have " + expectedLogLength + " entries.");
   checkEvent(log[log.length-2], TLOG.ACTIVATION_KEY,
              [TLOG.ACTIVATION.REJECTED, EXPERIMENT1_ID, "startTime"]);