1 files changed, 145 insertions, 0 deletions
diff --git a/toolkit/components/telemetry/tests/unit/test_TelemetryLateWrites.js b/toolkit/components/telemetry/tests/unit/test_TelemetryLateWrites.js
new file mode 100644
index 0000000000..36a77d0e2b
--- /dev/null
+++ b/toolkit/components/telemetry/tests/unit/test_TelemetryLateWrites.js
@@ -0,0 +1,145 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/
+*/
+/* A testcase to make sure reading late writes stacks works.  */
+
+ChromeUtils.import("resource://gre/modules/Services.jsm", this);
+
+// Constants from prio.h for nsIFileOutputStream.init
+const PR_WRONLY = 0x2;
+const PR_CREATE_FILE = 0x8;
+const PR_TRUNCATE = 0x20;
+const RW_OWNER = parseInt("0600", 8);
+
+const STACK_SUFFIX1 = "stack1.txt";
+const STACK_SUFFIX2 = "stack2.txt";
+const STACK_BOGUS_SUFFIX = "bogus.txt";
+const LATE_WRITE_PREFIX = "Telemetry.LateWriteFinal-";
+
+// The names and IDs don't matter, but the format of the IDs does.
+const LOADED_MODULES = {
+  "4759A7E6993548C89CAF716A67EC242D00": "libtest.so",
+  F77AF15BB8D6419FA875954B4A3506CA00: "libxul.so",
+  "1E2F7FB590424E8F93D60BB88D66B8C500": "libc.so",
+  E4D6D70CC09A63EF8B88D532F867858800: "libmodμles.so",
+};
+const N_MODULES = Object.keys(LOADED_MODULES).length;
+
+// Format of individual items is [index, offset-in-library].
+const STACK1 = [
+  [0, 0],
+  [1, 1],
+  [2, 2],
+  [3, 3],
+];
+const STACK2 = [
+  [0, 0],
+  [1, 5],
+  [2, 10],
+  [3, 15],
+];
+// XXX The only error checking is for a zero-sized stack.
+const STACK_BOGUS = [];
+
+function write_string_to_file(file, contents) {
+  let ostream = Cc[
+    "@mozilla.org/network/safe-file-output-stream;1"
+  ].createInstance(Ci.nsIFileOutputStream);
+  ostream.init(
+    file,
+    PR_WRONLY | PR_CREATE_FILE | PR_TRUNCATE,
+    RW_OWNER,
+    ostream.DEFER_OPEN
+  );
+
+  var bos = Cc["@mozilla.org/binaryoutputstream;1"].createInstance(
+    Ci.nsIBinaryOutputStream
+  );
+  bos.setOutputStream(ostream);
+
+  let utf8 = new TextEncoder("utf-8").encode(contents);
+  bos.writeByteArray(utf8);
+  ostream.QueryInterface(Ci.nsISafeOutputStream).finish();
+  ostream.close();
+}
+
+function construct_file(suffix) {
+  let profileDirectory = Services.dirsvc.get("ProfD", Ci.nsIFile);
+  let file = profileDirectory.clone();
+  file.append(LATE_WRITE_PREFIX + suffix);
+  return file;
+}
+
+function write_late_writes_file(stack, suffix) {
+  let file = construct_file(suffix);
+  let contents = N_MODULES + "\n";
+  for (let id in LOADED_MODULES) {
+    contents += id + " " + LOADED_MODULES[id] + "\n";
+  }
+
+  contents += stack.length + "\n";
+  for (let element of stack) {
+    contents += element[0] + " " + element[1].toString(16) + "\n";
+  }
+
+  write_string_to_file(file, contents);
+}
+
+function run_test() {
+  do_get_profile();
+
+  write_late_writes_file(STACK1, STACK_SUFFIX1);
+  write_late_writes_file(STACK2, STACK_SUFFIX2);
+  write_late_writes_file(STACK_BOGUS, STACK_BOGUS_SUFFIX);
+
+  let lateWrites = Telemetry.lateWrites;
+  Assert.ok("memoryMap" in lateWrites);
+  Assert.equal(lateWrites.memoryMap.length, 0);
+  Assert.ok("stacks" in lateWrites);
+  Assert.equal(lateWrites.stacks.length, 0);
+
+  do_test_pending();
+  Telemetry.asyncFetchTelemetryData(function() {
+    actual_test();
+  });
+}
+
+function actual_test() {
+  Assert.ok(!construct_file(STACK_SUFFIX1).exists());
+  Assert.ok(!construct_file(STACK_SUFFIX2).exists());
+  Assert.ok(!construct_file(STACK_BOGUS_SUFFIX).exists());
+
+  let lateWrites = Telemetry.lateWrites;
+
+  Assert.ok("memoryMap" in lateWrites);
+  Assert.equal(lateWrites.memoryMap.length, N_MODULES);
+  for (let id in LOADED_MODULES) {
+    let matchingLibrary = lateWrites.memoryMap.filter(function(
+      library,
+      idx,
+      array
+    ) {
+      return library[1] == id;
+    });
+    Assert.equal(matchingLibrary.length, 1);
+    let library = matchingLibrary[0];
+    let name = library[0];
+    Assert.equal(LOADED_MODULES[id], name);
+  }
+
+  Assert.ok("stacks" in lateWrites);
+  Assert.equal(lateWrites.stacks.length, 2);
+  let uneval_STACKS = [uneval(STACK1), uneval(STACK2)];
+  let first_stack = lateWrites.stacks[0];
+  let second_stack = lateWrites.stacks[1];
+  function stackChecker(canonicalStack) {
+    let unevalCanonicalStack = uneval(canonicalStack);
+    return function(obj, idx, array) {
+      return unevalCanonicalStack == obj;
+    };
+  }
+  Assert.equal(uneval_STACKS.filter(stackChecker(first_stack)).length, 1);
+  Assert.equal(uneval_STACKS.filter(stackChecker(second_stack)).length, 1);
+
+  do_test_finished();
+}