req, err := newTestSignedRequestV4(http.MethodHead, getHEADBucketURL("", testCase.bucketName), 0, nil, testCase.accessKey, testCase.secretKey, nil)
		if err != nil {
			t.Fatalf("Test %d: %s: Failed to create HTTP request for HeadBucketHandler: <ERROR> %v", i+1, instanceType, err)
		}
		// Since `apiRouter` satisfies `http.Handler` it has a ServeHTTP to execute the logic of the handler.
		// Call the ServeHTTP to execute the handler.

		// PutBucket
		router.Methods(http.MethodPut).
			HandlerFunc(s3APIMiddleware(api.PutBucketHandler))
		// HeadBucket
		router.Methods(http.MethodHead).
			HandlerFunc(s3APIMiddleware(api.HeadBucketHandler))
		// PostPolicy
		router.Methods(http.MethodPost).
			MatcherFunc(func(r *http.Request, _ *mux.RouteMatch) bool {
				return isRequestPostPolicySignatureV4(r)
			}).