1 files changed, 33 insertions, 0 deletions
diff --git a/src/features/counter/counterSlice.spec.js b/src/features/counter/counterSlice.spec.js
new file mode 100644
index 0000000..113526b
--- /dev/null
+++ b/src/features/counter/counterSlice.spec.js
@@ -0,0 +1,33 @@
+import counterReducer, {
+  increment,
+  decrement,
+  incrementByAmount,
+} from "./counterSlice";
+
+describe("counter reducer", () => {
+  const initialState = {
+    value: 3,
+    status: "idle",
+  };
+  it("should handle initial state", () => {
+    expect(counterReducer(undefined, { type: "unknown" })).toEqual({
+      value: 0,
+      status: "idle",
+    });
+  });
+
+  it("should handle increment", () => {
+    const actual = counterReducer(initialState, increment());
+    expect(actual.value).toEqual(4);
+  });
+
+  it("should handle decrement", () => {
+    const actual = counterReducer(initialState, decrement());
+    expect(actual.value).toEqual(2);
+  });
+
+  it("should handle incrementByAmount", () => {
+    const actual = counterReducer(initialState, incrementByAmount(2));
+    expect(actual.value).toEqual(5);
+  });
+});