1 files changed, 35 insertions, 0 deletions
diff --git a/packages/excalidraw/scene/selection.test.ts b/packages/excalidraw/scene/selection.test.ts
new file mode 100644
index 0000000..644d212
--- /dev/null
+++ b/packages/excalidraw/scene/selection.test.ts
@@ -0,0 +1,35 @@
+import { makeNextSelectedElementIds } from "./selection";
+
+describe("makeNextSelectedElementIds", () => {
+  const _makeNextSelectedElementIds = (
+    selectedElementIds: { [id: string]: true },
+    prevSelectedElementIds: { [id: string]: true },
+    expectUpdated: boolean,
+  ) => {
+    const ret = makeNextSelectedElementIds(selectedElementIds, {
+      selectedElementIds: prevSelectedElementIds,
+    });
+    expect(ret === selectedElementIds).toBe(expectUpdated);
+  };
+  it("should return prevState selectedElementIds if no change", () => {
+    _makeNextSelectedElementIds({}, {}, false);
+    _makeNextSelectedElementIds({ 1: true }, { 1: true }, false);
+    _makeNextSelectedElementIds(
+      { 1: true, 2: true },
+      { 1: true, 2: true },
+      false,
+    );
+  });
+  it("should return new selectedElementIds if changed", () => {
+    // _makeNextSelectedElementIds({ 1: true }, { 1: false }, true);
+    _makeNextSelectedElementIds({ 1: true }, {}, true);
+    _makeNextSelectedElementIds({}, { 1: true }, true);
+    _makeNextSelectedElementIds({ 1: true }, { 2: true }, true);
+    _makeNextSelectedElementIds({ 1: true }, { 1: true, 2: true }, true);
+    _makeNextSelectedElementIds(
+      { 1: true, 2: true },
+      { 1: true, 3: true },
+      true,
+    );
+  });
+});