elm-review/tests/NoUnusedExportsTest.elm

module NoUnusedExportsTest exposing (all)

import Elm.Constraint
import Elm.License
import Elm.Module
import Elm.Package
import Elm.Project
import Elm.Version
import NoUnusedExports exposing (rule)
import Review.Project as Project exposing (Project)
import Review.Test
import Test exposing (Test, describe, test)


application : Project
application =
    Project.new
        |> Project.withElmJson applicationElmJson


applicationElmJson : Elm.Project.Project
applicationElmJson =
    Elm.Project.Application
        { elm = Elm.Version.one
        , dirs = []
        , depsDirect = []
        , depsIndirect = []
        , testDepsDirect = []
        , testDepsIndirect = []
        }


package_ : Project
package_ =
    Project.new
        |> Project.withElmJson (createPackageElmJson ())


createPackageElmJson : () -> Elm.Project.Project
createPackageElmJson _ =
    case ( Elm.Package.fromString "author/package", Elm.Constraint.fromString "1.0.0 <= v < 2.0.0", Elm.Module.fromString "Exposed" ) of
        ( Just name, Just elm, Just moduleName ) ->
            Elm.Project.Package
                { name = name
                , summary = "Summary"
                , license = Elm.License.bsd3
                , version = Elm.Version.one
                , exposed = Elm.Project.ExposedList [ moduleName ]
                , deps = []
                , testDeps = []
                , elm = elm
                }

        _ ->
            createPackageElmJson ()


details : List String
details =
    [ "This exposed element is never used. You may want to remove it to keep your project clean, and maybe detect some unused code in your project."
    ]


all : Test
all =
    describe "NoUnusedExports"
        [ functionsAndValuesTests
        , typesTests

        -- TODO Add tests that report exposing the type's variants if they are never used.
        ]


functionsAndValuesTests : Test
functionsAndValuesTests =
    describe "Functions and values"
        [ test "should report an exposed function when it is not used in other modules" <|
            \() ->
                """
module A exposing (a)
a = 1
"""
                    |> Review.Test.runWithProjectData application rule
                    |> Review.Test.expectErrors
                        [ Review.Test.error
                            { message = "Exposed function or value `a` is never used outside this module."
                            , details = details
                            , under = "a"
                            }
                            |> Review.Test.atExactly { start = { row = 2, column = 20 }, end = { row = 2, column = 21 } }
                        ]
        , test "should not report an exposed function when it is used in other modules (qualified import)" <|
            \() ->
                [ """
module A exposing (a)
a = 1
""", """
module B exposing (main)
import A
main = A.a
""" ]
                    |> Review.Test.runOnModulesWithProjectData application rule
                    |> Review.Test.expectNoErrors
        , test "should not report an exposed function when it is used in other modules (using an alias)" <|
            \() ->
                [ """
module A exposing (a)
a = 1
""", """
module B exposing (main)
import A as SomeA
main = SomeA.a
""" ]
                    |> Review.Test.runOnModulesWithProjectData application rule
                    |> Review.Test.expectNoErrors
        , test "should not report an exposed function when it is used in other modules (using `exposing` to import)" <|
            \() ->
                [ """
module A exposing (a)
a = 1
""", """
module B exposing (main)
import A exposing (a)
main = a
""" ]
                    |> Review.Test.runOnModulesWithProjectData application rule
                    |> Review.Test.expectNoErrors
        , test "should not report an exposed function when it is used in other modules (using `exposing(..)` to import)" <|
            \() ->
                [ """
module A exposing (a)
a = 1
""", """
module B exposing (main)
import A exposing (..)
main = a
""" ]
                    |> Review.Test.runOnModulesWithProjectData application rule
                    |> Review.Test.expectNoErrors
        , test "should report an exposed function when it is not used in other modules, even if it is used in the module" <|
            \() ->
                """
module A exposing (exposed)
exposed = 1
main = exposed
"""
                    |> Review.Test.runWithProjectData package_ rule
                    |> Review.Test.expectErrors
                        [ Review.Test.error
                            { message = "Exposed function or value `exposed` is never used outside this module."
                            , details = details
                            , under = "exposed"
                            }
                            |> Review.Test.atExactly { start = { row = 2, column = 20 }, end = { row = 2, column = 27 } }
                        ]
        , test "should not report anything for modules that expose everything`" <|
            \() ->
                """
module A exposing (..)
a = 1
"""
                    |> Review.Test.runWithProjectData package_ rule
                    |> Review.Test.expectNoErrors
        , test "should not report the `main` function for an application even if it is unused" <|
            \() ->
                """
module Main exposing (main)
main = text ""
"""
                    |> Review.Test.runWithProjectData application rule
                    |> Review.Test.expectNoErrors
        , test "should report the `main` function for a package when it is never used outside the module" <|
            \() ->
                """
module Main exposing (main)
main = text ""
"""
                    |> Review.Test.runWithProjectData package_ rule
                    |> Review.Test.expectErrors
                        [ Review.Test.error
                            { message = "Exposed function or value `main` is never used outside this module."
                            , details = details
                            , under = "main"
                            }
                            |> Review.Test.atExactly { start = { row = 2, column = 23 }, end = { row = 2, column = 27 } }
                        ]
        , test "should not report a function that does not refer to anything" <|
            \() ->
                """
module A exposing (b)
a = 1
"""
                    |> Review.Test.runWithProjectData package_ rule
                    |> Review.Test.expectNoErrors
        ]


typesTests : Test
typesTests =
    describe "Types"
        [ test "should report an unused exposed custom type" <|
            \() ->
                """
module A exposing (Exposed)
type Exposed = VariantA | VariantB
"""
                    |> Review.Test.runWithProjectData application rule
                    |> Review.Test.expectErrors
                        [ Review.Test.error
                            { message = "Exposed type or type alias `Exposed` is never used outside this module."
                            , details = details
                            , under = "Exposed"
                            }
                            |> Review.Test.atExactly { start = { row = 2, column = 20 }, end = { row = 2, column = 27 } }
                        ]
        , test "should not report a used exposed custom type (type signature)" <|
            \() ->
                [ """
module A exposing (Exposed)
type Exposed = VariantA | VariantB
""", """
module B exposing (main)
import A
main : A.Exposed
main = VariantA
""" ]
                    |> Review.Test.runOnModulesWithProjectData application rule
                    |> Review.Test.expectNoErrors
        , Test.skip <|
            test "should not report a used exposed custom type (type alias)" <|
                \() ->
                    [ """
module A exposing (ExposedB, ExposedC)
type ExposedB = B
type ExposedC = C
""", """
module Exposed exposing (B, C)
import A
type alias B = A.ExposedB
type alias C = A.ExposedC
""" ]
                        |> Review.Test.runOnModulesWithProjectData package_ rule
                        |> Review.Test.expectNoErrors
        , test "should not report an unused exposed custom type if it's part of the package's exposed API" <|
            \() ->
                """
module Exposed exposing (MyType)
type MyType = VariantA | VariantB
"""
                    |> Review.Test.runWithProjectData package_ rule
                    |> Review.Test.expectNoErrors
        , test "should not report an unused exposed custom type if it's present in the signature of an exposed function" <|
            \() ->
                """
module A exposing (main, MyType)
type MyType = VariantA | VariantB
main : () -> MyType
main = 1
"""
                    |> Review.Test.runWithProjectData application rule
                    |> Review.Test.expectNoErrors
        , Test.skip <|
            test "should not report an unused exposed custom type if it's aliased by an exposed type alias" <|
                \() ->
                    [ """
module A exposing (MyType, OtherType)
type MyType = VariantA | VariantB
type alias OtherType = MyType
""", """
module Exposed exposing (..)
import A
type alias B = A.OtherType
""" ]
                        |> Review.Test.runOnModulesWithProjectData package_ rule
                        |> Review.Test.expectNoErrors
        , Test.skip <|
            test "should not report an unused exposed custom type if it's present in an exposed type alias" <|
                \() ->
                    [ """
module A exposing (MyType, OtherType)
type MyType = VariantA | VariantB
type alias OtherType = { thing : MyType }
""", """
module Exposed exposing (..)
import A
type alias B = A.OtherType
""" ]
                        |> Review.Test.runOnModulesWithProjectData package_ rule
                        |> Review.Test.expectNoErrors
        , Test.skip <|
            test "should not report an unused exposed custom type if it's present in an exposed type alias (nested)" <|
                \() ->
                    [ """
module A exposing (MyType, OtherType)
type MyType = VariantA | VariantB
type alias OtherType = { other { thing : ((), MyType) } }
""", """
module Exposed exposing (..)
import A
type alias B = A.OtherType
""" ]
                        |> Review.Test.runOnModulesWithProjectData package_ rule
                        |> Review.Test.expectNoErrors
        , Test.skip <|
            test "should not report an unused exposed custom type if it's present in an exposed custom type constructor's arguments" <|
                \() ->
                    [ """
module A exposing (MyType, OtherType)
type MyType = VariantA | VariantB
type OtherType = Thing MyType
""", """
module Exposed exposing (..)
import A
type alias B = A.OtherType
""" ]
                        |> Review.Test.runOnModulesWithProjectData package_ rule
                        |> Review.Test.expectNoErrors
        , Test.skip <|
            test "should not report an unused exposed custom type if it's present in an exposed custom type constructor's arguments (nested)" <|
                \() ->
                    [ """
module A exposing (MyType, OtherType)
type MyType = VariantA | VariantB
type OtherType = OtherThing | SomeThing ((), List MyType)
""", """
module Exposed exposing (..)
import A
type alias B = A.OtherType
""" ]
                        |> Review.Test.runOnModulesWithProjectData package_ rule
                        |> Review.Test.expectNoErrors
        ]