False positives in test functions

[kioan000]

Using "in-module" test configuration if my test is using an update function it can happen that rule reports a false positive

[jfmengels]

Hi @kioan000

I'm not sure I understand the issue. Can you clarify what you mean with "in-module" test configuration? And would it be possible for you to provide an SSCCE?

[kioan000]

You're right sorry.
In this project I've configured elm-test to keep test functions within the source modules instead of having an external test folder. The project have a quite strict elm-review configuration (almost 30-35 review rules)

Unluckily it regards code from a private organization so I can't share the repository and despite my efforts I didn't succeed in reproducing a simplified example since I can't find a common pattern. It's a very bizarre case

For example in the following situation

port module Lib.CookieBar exposing (CookieBar, init, subscriptions, view, update, test)

import Lib.Logger as Logger
...

update : Msg -> CookieBar msg -> ( CookieBar msg, Cmd msg )
update msg model =
    case msg of
        ...

        SubError error ->
            model
                |> PrimaUpdate.withCmds
                    [ Logger.devConsoleErrorForJsonDecodeError
                        { location = "CookieBar subscription port is used wrongly: "
                        , error = error
                        }
                    ]

test : Test
test =
    Test.describe "Lib.CookieBar tests"
        [ updateTest
        ]
        
updateTest : Test
updateTest =
    Test.describe "Test over update function"
        [ Test.test "Tests init state"
            (\() ->
                init (always ())
                    |> isVisible
                    |> Expect.false "Cookie bar should be invisibile at init"
            )
        ] 

everything works fine. But if I add a test that calls my update:

updateTest : Test
updateTest =
    Test.describe "Test over update function"
        [ Test.test "Tests init state"
            (\() ->
                init (always ())
                    |> isVisible
                    |> Expect.false "Cookie bar should be invisibile at init"
            )
       , Test.test "Visible flag should be True when cookies acceptance is not present"
            (\() ->
                init (always ())
                    |> update (HasCookiesAcceptance False)
                    |> Tuple.first
                    |> isVisible
                    |> Expect.true "Cookie bar should be visible"
            )
        ] 

Then the rule notices not only that CookieBar.test calls a port inside Logger module, but suddenly reports the same thing in Lib.Authenticator.test (which calls the same port through its update function) that previously wasn't noticed

-- ELM-REVIEW ERROR --------------------------------- web-app/Lib/Logger.elm:8:6

NoUnusedPorts: Port `loggerPort_` is never used (Warning: can cause JS runtime
errors)

8| port loggerPort_ : JsonEncode.Value -> Cmd msg
        ^^^^^^^^^^^

Unused ports are not available in the compiled JavaScript and can cause runtime
errors when you try to access them.

You should either use this port somewhere, or remove it at the location I
pointed at. This may highlight some other unused code in your project too.

Warning: If you remove this port, remember to remove any calls to it in your
JavaScript code too.

I found this port called by the following functions, but none of them trace back
to a `main` function:

-> Lib.CookieBar.test
-> **Lib.Http.Authenticator.test**
-> Lib.Logger.devConsoleErrorForHttp
-> Lib.Logger.devConsoleErrorForJsonDecodeError
-> Lib.Logger.devConsoleLog
-> Lib.Logger.devConsoleWarn