1 files changed, 69 insertions, 0 deletions
diff --git a/js/xpconnect/tests/unit/test_onGarbageCollection-01.js b/js/xpconnect/tests/unit/test_onGarbageCollection-01.js
new file mode 100644
index 0000000000..81ac713865
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_onGarbageCollection-01.js
@@ -0,0 +1,69 @@
+// Test basic usage of onGarbageCollection
+
+const root = newGlobal();
+const dbg = new Debugger();
+const wrappedRoot = dbg.addDebuggee(root)
+
+const NUM_SLICES = root.NUM_SLICES = 10;
+
+let fired = false;
+let slicesFound = 0;
+
+Services.prefs.setBoolPref("security.allow_eval_with_system_principal", true);
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref("security.allow_eval_with_system_principal");
+});
+
+dbg.memory.onGarbageCollection = data => {
+  fired = true;
+
+  print("Got onGarbageCollection: " + JSON.stringify(data, null, 2));
+
+  equal(typeof data.reason, "string");
+  equal(typeof data.nonincrementalReason == "string" || data.nonincrementalReason === null,
+        true);
+
+  let lastStartTimestamp = 0;
+  for (let i = 0; i < data.collections.length; i++) {
+    let slice = data.collections[i];
+
+    equal(slice.startTimestamp >= lastStartTimestamp, true);
+    equal(slice.startTimestamp <= slice.endTimestamp, true);
+
+    lastStartTimestamp = slice.startTimestamp;
+  }
+
+  equal(data.collections.length >= 1, true);
+  slicesFound += data.collections.length;
+}
+
+function run_test() {
+  do_test_pending();
+
+  root.eval(
+    `
+    this.allocs = [];
+
+    // GC slices
+    for (var i = 0; i < NUM_SLICES; i++) {
+      this.allocs.push({});
+      gcslice();
+    }
+
+    // Full GC
+    this.allocs.push({});
+    gc();
+    `
+  );
+
+  executeSoon(() => {
+    equal(fired, true, "The GC hook should have fired at least once");
+
+    // NUM_SLICES + 1 full gc + however many were triggered naturally (due to
+    // whatever zealousness setting).
+    print("Found " + slicesFound + " slices");
+    equal(slicesFound >= NUM_SLICES + 1, true);
+
+    do_test_finished();
+  });
+}