diff --git a/packages/bezier-react/src/features/SmoothCornersFeature/SmoothCornersFeatures.test.ts b/packages/bezier-react/src/features/SmoothCornersFeature/SmoothCornersFeatures.test.ts
new file mode 100644
index 0000000000..ed65dbf7d7
--- /dev/null
+++ b/packages/bezier-react/src/features/SmoothCornersFeature/SmoothCornersFeatures.test.ts
@@ -0,0 +1,34 @@
+import SmoothCornersFeature from './SmoothCornersFeature'
+
+describe('SmoothCornersFeature', () => {
+  let addModule: jest.Mock
+
+  beforeEach(() => {
+    addModule = jest.fn(() => Promise.resolve())
+
+    Object.defineProperty(global, 'URL', {
+      value: {
+        createObjectURL: jest.fn(),
+      },
+    })
+
+    Object.defineProperty(global, 'CSS', {
+      value: {
+        paintWorklet: { addModule },
+      },
+    })
+  })
+
+  it('If the global objects are the same, activate should only be executed once.', async () => {
+    await SmoothCornersFeature.activate(globalThis)
+    await SmoothCornersFeature.activate(globalThis)
+    expect(addModule).toHaveBeenCalledTimes(1)
+  })
+
+  it('If the global object has changed, activate should be executed again.', async () => {
+    await SmoothCornersFeature.activate(globalThis)
+    expect(addModule).toHaveBeenCalledTimes(0)
+    await SmoothCornersFeature.activate({ ...globalThis })
+    expect(addModule).toHaveBeenCalledTimes(1)
+  })
+})