1 files changed, 72 insertions, 0 deletions
diff --git a/devtools/client/memory/test/xpcshell/test_action-set-display.js b/devtools/client/memory/test/xpcshell/test_action-set-display.js
new file mode 100644
index 0000000000..5b4bc58d3c
--- /dev/null
+++ b/devtools/client/memory/test/xpcshell/test_action-set-display.js
@@ -0,0 +1,72 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * Tests the action creator `setCensusDisplay()` for display changing. Does not
+ * test refreshing the census information, check `setCensusDisplayAndRefresh`
+ * action for that.
+ */
+
+const {
+  censusDisplays,
+  censusState,
+  viewState,
+} = require("devtools/client/memory/constants");
+const {
+  setCensusDisplay,
+} = require("devtools/client/memory/actions/census-display");
+const {
+  takeSnapshotAndCensus,
+} = require("devtools/client/memory/actions/snapshot");
+const { changeView } = require("devtools/client/memory/actions/view");
+
+// We test setting an invalid display, which triggers an assertion failure.
+EXPECTED_DTU_ASSERT_FAILURE_COUNT = 1;
+
+add_task(async function() {
+  const front = new StubbedMemoryFront();
+  const heapWorker = new HeapAnalysesClient();
+  await front.attach();
+  const store = Store();
+  const { getState, dispatch } = store;
+
+  dispatch(changeView(viewState.CENSUS));
+
+  // Test default display with no snapshots
+  equal(
+    getState().censusDisplay.breakdown.by,
+    "coarseType",
+    "default coarseType display selected at start."
+  );
+
+  dispatch(setCensusDisplay(censusDisplays.allocationStack));
+  equal(
+    getState().censusDisplay.breakdown.by,
+    "allocationStack",
+    "display changed with no snapshots"
+  );
+
+  // Test invalid displays
+  try {
+    dispatch(setCensusDisplay({}));
+    ok(false, "Throws when passing in an invalid display object");
+  } catch (e) {
+    ok(true, "Throws when passing in an invalid display object");
+  }
+  equal(
+    getState().censusDisplay.breakdown.by,
+    "allocationStack",
+    "current display unchanged when passing invalid display"
+  );
+
+  // Test new snapshots
+  dispatch(takeSnapshotAndCensus(front, heapWorker));
+  await waitUntilCensusState(store, s => s.census, [censusState.SAVED]);
+  equal(
+    getState().snapshots[0].census.display,
+    censusDisplays.allocationStack,
+    "New snapshots use the current, non-default display"
+  );
+});