In the book Practical Go chapter 3 - pkgregister-data/pkgregister_test.go, we only give single parameters for this code: ```go func TestRegisterPackageData(t *testing.T) { // ... pResult, err := registerPackageData(ts.URL) // ... } ``` It will throw an error when running the test because of `not enough arguments in call to registerPackageData`. ```shell # github.com/rikyhidayat21/pkgregister-data [github.com/rikyhidayat21/pkgregister-data.test] /Users/riky/Dev/learning-go/goprac/ch3/pkgregister-data/pkgregister_test.go:55:38: not enough arguments in call to registerPackageData have (string) want (*http.Client, string, pkgData) FAIL github.com/rikyhidayat21/pkgregister-data [build failed] FAIL ``` The solution we need to add appropriate parameters as it is. It should be like this: ```go func TestRegisterPackageData(t *testing.T) { // ... pResult, err := registerPackageData(createHTTPClientWithTimeout(1000), ts.URL, p) // ... } ``` Then if we run the test, now it will be pass.