Bug 878458 - improve error handling behavior of telemetry ping tests; r=vladan

toolkit/components/telemetry/tests/unit/test_TelemetryPing.js

@@ -56,18 +56,38 @@ function dummyHandler(request, response) {
   return p;
 }
 
+function wrapWithExceptionHandler(f) {
+  function wrapper() {
+    try {
+      f.apply(null, arguments);
+    } catch (ex if typeof(ex) == 'object') {
+      dump("Caught exception: " + ex.message + "\n");
+      dump(ex.stack);
+      do_test_finished();
+    }
+  }
+  return wrapper;
+}
+
+function addWrappedObserver(f, topic) {
+  let wrappedObserver = wrapWithExceptionHandler(f);
+  Services.obs.addObserver(function g(aSubject, aTopic, aData) {
+    Services.obs.removeObserver(g, aTopic);
+    wrappedObserver(aSubject, aTopic, aData);
+  }, topic, false);
+}
+
 function registerPingHandler(handler) {
-  httpserver.registerPathHandler(TelemetryPing.submissionPath(), handler);
+  httpserver.registerPathHandler(TelemetryPing.submissionPath(),
+				 wrapWithExceptionHandler(handler));
 }
 
 function nonexistentServerObserver(aSubject, aTopic, aData) {
-  Services.obs.removeObserver(nonexistentServerObserver, aTopic);
-
   httpserver.start(4444);
 
   // Provide a dummy function so it returns 200 instead of 404 to telemetry.
   registerPingHandler(dummyHandler);
-  Services.obs.addObserver(telemetryObserver, "telemetry-test-xhr-complete", false);
+  addWrappedObserver(telemetryObserver, "telemetry-test-xhr-complete");
   telemetry_ping();
 }
 
@@ -98,7 +118,6 @@ function getSavedHistogramsFile(basename) {
 }
 
 function telemetryObserver(aSubject, aTopic, aData) {
-  Services.obs.removeObserver(telemetryObserver, aTopic);
   registerPingHandler(checkHistogramsSync);
   let histogramsFile = getSavedHistogramsFile("saved-histograms.dat");
   setupTestData();
@@ -275,7 +294,7 @@ function checkPersistedHistogramsSync(request, response) {
   // saved.
   checkPayload(request, "saved-session", 1);
 
-  Services.obs.addObserver(runAsyncTestObserver, "telemetry-test-xhr-complete", false);
+  addWrappedObserver(runAsyncTestObserver, "telemetry-test-xhr-complete");
 }
 
 function checkHistogramsSync(request, response) {
@@ -284,20 +303,16 @@ function checkHistogramsSync(request, response) {
 }
 
 function runAsyncTestObserver(aSubject, aTopic, aData) {
-  Services.obs.removeObserver(runAsyncTestObserver, aTopic);
   registerPingHandler(checkHistogramsAsync);
   let histogramsFile = getSavedHistogramsFile("saved-histograms2.dat");
 
-  Services.obs.addObserver(function(aSubject, aTopic, aData) {
-    Services.obs.removeObserver(arguments.callee, aTopic);
-
-    Services.obs.addObserver(function(aSubject, aTopic, aData) {
-      Services.obs.removeObserver(arguments.callee, aTopic);
+  addWrappedObserver(function(aSubject, aTopic, aData) {
+    addWrappedObserver(function(aSubject, aTopic, aData) {
       telemetry_ping();
-    }, "telemetry-test-load-complete", false);
+    }, "telemetry-test-load-complete");
 
     TelemetryPing.testLoadHistograms(histogramsFile, false);
-  }, "telemetry-test-save-complete", false);
+  }, "telemetry-test-save-complete");
   TelemetryPing.saveHistograms(histogramsFile, false);
 }
 
@@ -309,9 +324,9 @@ function checkPersistedHistogramsAsync(request, response) {
   // saved.
   checkPayload(request, "saved-session", 3);
 
-  gFinished = true;
-
   runOldPingFileTest();
+
+  gFinished = true;
 }
 
 function checkHistogramsAsync(request, response) {
@@ -501,12 +516,12 @@ function run_test() {
     });
   });
 
-  Telemetry.asyncFetchTelemetryData(function () {
-    actualTest();
-  });
+  Telemetry.asyncFetchTelemetryData(wrapWithExceptionHandler(actualTest));
 }
 
 function actualTest() {
+  // ensure that test runs to completion
+  do_register_cleanup(function () do_check_true(gFinished));
   // try to make LightweightThemeManager do stuff
   let gInternalManager = Cc["@mozilla.org/addons/integration;1"]
                          .getService(Ci.nsIObserver)
@@ -520,11 +535,9 @@ function actualTest() {
 
   runInvalidJSONTest();
 
-  Services.obs.addObserver(nonexistentServerObserver, "telemetry-test-xhr-complete", false);
+  addWrappedObserver(nonexistentServerObserver, "telemetry-test-xhr-complete");
   telemetry_ping();
   // spin the event loop
   do_test_pending();
-  // ensure that test runs to completion
-  do_register_cleanup(function () do_check_true(gFinished));
   do_test_finished();
 }