Go Unit-Testing fatals and testing main()

manpreet Best Answer 2 years ago

I'm pretty new to go testing coming from a background of PHP with PHPUnit tests.

In PHP it's pretty much reliously preached that you need 100% coverage. In Go most stuff i've read about tests seem to minimal, without stuff like provoking errors.

For example my small program:

func main() {
    config = readConfig("config.json")
}

func readConfig(path string) Config {
    var cfg Config
    file, err := ioutil.ReadFile(path)
    if err != nil {
        log.Fatal(err)
    }
    err = json.Unmarshal(file, &cfg)
    if err != nil {
        log.Fatal(err)
    }
    return cfg
}

func TestCanReadConfig(t *testing.T) {
    cfg := readConfig("test_data/config.json")
    if cfg.Broker_pass != "test" || cfg.Broker_port != "3333" {
        t.Error("invalid config")
    }
}

now in my example I would have issues with coverage because main() isn't covered at all in Unit tests (How should it?)

And the 2 log.Fatal()'s are not covered at all.

My question is how do I write my tests exactly in go? Do I do it in a less strict style not testing every possible scenario or can I do annotation like in php with @expectedException \InvalidArgumentException Can I or should I test the main function? If not can I ignore it from the coverage tool somehow? Should I consider a testing framework? Most testing tutorial are nice but very short and only introducing simple tests.

manpreet 2 years ago

func readConfig(path string) (Config, error) {
    var cfg Config
    file, err := ioutil.ReadFile(path)
    if err != nil {
        return cfg, err
    }
    err = json.Unmarshal(file, &cfg)
    if err != nil {
        return cfg, err
    }
    return cfg, nil
}

func main() {
    config, err := readConfig("config.json")
    if err != nil {
        log.Fatal(err)
    }

}