add additional test

packages/browser/src/lib/__tests__/fetch.test.ts

@@ -11,16 +11,30 @@ const getGlobalMock = jest.mocked(getGlobal)
 describe(fetch, () => {
   const testFetchArgs = ['http://foo.com', {}] as const
 
-  it('should call native fetch if available', async () => {
-    const nativeFetchSpy = jest.fn()
-    getGlobalMock.mockReturnValue({ ...window, fetch: nativeFetchSpy })
+  it('should call native fetch if available', () => {
+    const nativeFetchMock = jest.fn()
+    getGlobalMock.mockReturnValue({ ...window, fetch: nativeFetchMock })
     void fetch(...testFetchArgs)
-    expect(nativeFetchSpy).toBeCalledWith(...testFetchArgs)
+    expect(nativeFetchMock).toBeCalledWith(...testFetchArgs)
     expect(unfetchMock).not.toBeCalled()
   })
-  it('should fall back to unfetch', async () => {
+  it('should fall back to unfetch in non-browserlike environment', () => {
     getGlobalMock.mockReturnValue(null)
     void fetch(...testFetchArgs)
     expect(unfetchMock).toBeCalledWith(...testFetchArgs)
   })
+  it('should fall back to unfetch if fetch is unsupported', () => {
+    getGlobalMock.mockReturnValue({} as typeof globalThis)
+    void fetch(...testFetchArgs)
+    expect(unfetchMock).toBeCalledWith(...testFetchArgs)
+  })
+  it('should fall back to unfetch if fetch is unsupported', () => {
+    getGlobalMock.mockReturnValue({
+      ...window,
+      fetch: undefined,
+    } as any)
+
+    void fetch(...testFetchArgs)
+    expect(unfetchMock).toBeCalledWith(...testFetchArgs)
+  })
 })