diff --git a/src/__tests__/Squawk.update.test.ts b/src/__tests__/Squawk.update.test.ts
new file mode 100644
index 0000000..ced1a93
--- /dev/null
+++ b/src/__tests__/Squawk.update.test.ts
@@ -0,0 +1,31 @@
+import createStore from "../Squawk";
+
+describe("Squawk update", () => {
+  it("updates partial state correctly", () => {
+    const store = createStore({
+      prop1: "initial1",
+      prop2: "initial2"
+    });
+
+    store.update({ prop1: "updated1" });
+
+    expect(store.get()).toEqual({
+      prop1: "updated1",
+      prop2: "initial2"
+    });
+  });
+
+  it("updates multiple properties correctly", () => {
+    const store = createStore({
+      prop1: "initial1",
+      prop2: "initial2"
+    });
+
+    store.update({ prop1: "updated1", prop2: "updated2" });
+
+    expect(store.get()).toEqual({
+      prop1: "updated1",
+      prop2: "updated2"
+    });
+  });
+});