1 files changed, 61 insertions, 0 deletions
diff --git a/devtools/client/memory/test/xpcshell/test_action-take-snapshot.js b/devtools/client/memory/test/xpcshell/test_action-take-snapshot.js
new file mode 100644
index 0000000000..e8bd46898c
--- /dev/null
+++ b/devtools/client/memory/test/xpcshell/test_action-take-snapshot.js
@@ -0,0 +1,61 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * Tests the async reducer responding to the action `takeSnapshot(front)`
+ */
+
+const actions = require("resource://devtools/client/memory/actions/snapshot.js");
+const {
+  snapshotState: states,
+} = require("resource://devtools/client/memory/constants.js");
+
+add_task(async function () {
+  const front = new StubbedMemoryFront();
+  await front.attach();
+  const store = Store();
+
+  const unsubscribe = store.subscribe(checkState);
+
+  let foundPendingState = false;
+  let foundDoneState = false;
+
+  function checkState() {
+    const { snapshots } = store.getState();
+    const lastSnapshot = snapshots[snapshots.length - 1];
+
+    if (lastSnapshot.state === states.SAVING) {
+      foundPendingState = true;
+      ok(
+        foundPendingState,
+        "Got state change for pending heap snapshot request"
+      );
+      ok(!lastSnapshot.path, "Snapshot does not yet have a path");
+      ok(!lastSnapshot.census, "Has no census data when loading");
+    } else if (lastSnapshot.state === states.SAVED) {
+      foundDoneState = true;
+      ok(
+        foundDoneState,
+        "Got state change for completed heap snapshot request"
+      );
+      ok(foundPendingState, "SAVED state occurs after SAVING state");
+      ok(lastSnapshot.path, "Snapshot fetched with a path");
+      ok(
+        snapshots.every(s => s.selected === (s.id === lastSnapshot.id)),
+        "Only recent snapshot is selected"
+      );
+    }
+  }
+
+  for (let i = 0; i < 4; i++) {
+    store.dispatch(actions.takeSnapshot(front));
+    await waitUntilState(store, () => foundPendingState && foundDoneState);
+
+    // reset state trackers
+    foundDoneState = foundPendingState = false;
+  }
+
+  unsubscribe();
+});