1 files changed, 87 insertions, 0 deletions
diff --git a/devtools/shared/commands/target/tests/browser_watcher_actor_getter_caching.js b/devtools/shared/commands/target/tests/browser_watcher_actor_getter_caching.js
new file mode 100644
index 0000000000..6dd99d243b
--- /dev/null
+++ b/devtools/shared/commands/target/tests/browser_watcher_actor_getter_caching.js
@@ -0,0 +1,87 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Test that watcher front/actor APIs do not lead to create duplicate actors.
+
+const TEST_URL = "data:text/html;charset=utf-8,Actor caching test";
+
+add_task(async function () {
+  info("Setup the test page with workers of all types");
+  const tab = await addTab(TEST_URL);
+
+  info("Create a target list for a tab target");
+  const commands = await CommandsFactory.forTab(tab);
+  const targetCommand = commands.targetCommand;
+  await targetCommand.startListening();
+
+  const { watcherFront } = targetCommand;
+  ok(watcherFront, "A watcherFront is available on targetCommand");
+
+  info("Check that getNetworkParentActor does not create duplicate actors");
+  testActorGetter(
+    watcherFront,
+    () => watcherFront.getNetworkParentActor(),
+    "networkParent"
+  );
+
+  info("Check that getBreakpointListActor does not create duplicate actors");
+  testActorGetter(
+    watcherFront,
+    () => watcherFront.getBreakpointListActor(),
+    "breakpoint-list"
+  );
+
+  info(
+    "Check that getTargetConfigurationActor does not create duplicate actors"
+  );
+  testActorGetter(
+    watcherFront,
+    () => watcherFront.getTargetConfigurationActor(),
+    "target-configuration"
+  );
+
+  info(
+    "Check that getThreadConfigurationActor does not create duplicate actors"
+  );
+  testActorGetter(
+    watcherFront,
+    () => watcherFront.getThreadConfigurationActor(),
+    "thread-configuration"
+  );
+
+  targetCommand.destroy();
+  await commands.waitForRequestsToSettle();
+  await commands.destroy();
+});
+
+/**
+ * Check that calling an actor getter method on the watcher front leads to the
+ * creation of at most 1 actor.
+ */
+async function testActorGetter(watcherFront, actorGetterFn, typeName) {
+  checkPoolChildrenSize(watcherFront, typeName, 0);
+
+  const actor = await actorGetterFn();
+  checkPoolChildrenSize(watcherFront, typeName, 1);
+
+  const otherActor = await actorGetterFn();
+  is(actor, otherActor, "Returned the same actor for " + typeName);
+
+  checkPoolChildrenSize(watcherFront, typeName, 1);
+}
+
+/**
+ * Assert that a given parent pool has the expected number of children for
+ * a given typeName.
+ */
+function checkPoolChildrenSize(parentPool, typeName, expected) {
+  const children = [...parentPool.poolChildren()];
+  const childrenByType = children.filter(pool => pool.typeName === typeName);
+  is(
+    childrenByType.length,
+    expected,
+    `${parentPool.actorID} should have ${expected} children of type ${typeName}`
+  );
+}