diff --git a/example/greet.hs b/example/greet.hs --- a/example/greet.hs +++ b/example/greet.hs @@ -34,7 +34,7 @@ :<|> "greet" :> ReqBody '[JSON] Greet :> Post '[JSON] Greet -- DELETE /greet/:greetid - :<|> "greet" :> Capture "greetid" Text :> Delete '[JSON] () + :<|> "greet" :> Capture "greetid" Text :> Delete '[JSON] NoContent testApi :: Proxy TestApi testApi = Proxy @@ -54,7 +54,7 @@ postGreetH greet = return greet - deleteGreetH _ = return () + deleteGreetH _ = return NoContent -- Turn the server into a WAI app. 'serve' is provided by servant, -- more precisely by the Servant.Server module. diff --git a/servant-server.cabal b/servant-server.cabal --- a/servant-server.cabal +++ b/servant-server.cabal @@ -1,5 +1,5 @@ name: servant-server -version: 0.7.1 +version: 0.8 synopsis: A family of combinators for defining webservices APIs and serving them description: A family of combinators for defining webservices APIs and serving them @@ -45,31 +45,31 @@ Servant.Server.Internal.ServantErr Servant.Utils.StaticFiles build-depends: - base >= 4.7 && < 5 - , base-compat >= 0.9 + base >= 4.7 && < 4.10 + , base-compat >= 0.9 && < 0.10 , aeson >= 0.7 && < 0.12 , attoparsec >= 0.12 && < 0.14 - , base64-bytestring == 1.0.* + , base64-bytestring >= 1.0 && < 1.1 , bytestring >= 0.10 && < 0.11 , containers >= 0.5 && < 0.6 , http-api-data >= 0.1 && < 0.3 , http-types >= 0.8 && < 0.10 , network-uri >= 2.6 && < 2.7 - , mtl >= 2 && < 3 + , mtl >= 2 && < 2.3 , network >= 2.6 && < 2.7 , safe >= 0.3 && < 0.4 - , servant == 0.7.* + , servant == 0.8.* , split >= 0.2 && < 0.3 , string-conversions >= 0.3 && < 0.5 , system-filepath >= 0.4 && < 0.5 - , filepath >= 1 + , filepath >= 1 && < 1.5 , text >= 1.2 && < 1.3 , transformers >= 0.3 && < 0.6 - , transformers-compat>= 0.4 + , transformers-compat>= 0.4 && < 0.6 , wai >= 3.0 && < 3.3 - , wai-app-static >= 3.0 && < 3.2 + , wai-app-static >= 3.1 && < 3.2 , warp >= 3.0 && < 3.3 - , word8 == 0.1.* + , word8 >= 0.1 && < 0.2 hs-source-dirs: src default-language: Haskell2010 diff --git a/src/Servant/Server.hs b/src/Servant/Server.hs --- a/src/Servant/Server.hs +++ b/src/Servant/Server.hs @@ -95,6 +95,9 @@ , err504 , err505 + -- * Re-exports + , Application + ) where import Data.Proxy (Proxy) @@ -127,11 +130,11 @@ -- > main :: IO () -- > main = Network.Wai.Handler.Warp.run 8080 app -- -serve :: (HasServer layout '[]) => Proxy layout -> Server layout -> Application +serve :: (HasServer api '[]) => Proxy api -> Server api -> Application serve p = serveWithContext p EmptyContext -serveWithContext :: (HasServer layout context) - => Proxy layout -> Context context -> Server layout -> Application +serveWithContext :: (HasServer api context) + => Proxy api -> Context context -> Server api -> Application serveWithContext p context server = toApplication (runRouter (route p context (emptyDelayed (Route server)))) @@ -144,7 +147,7 @@ -- For the following API -- -- > type API = --- > "a" :> "d" :> Get '[JSON] () +-- > "a" :> "d" :> Get '[JSON] NoContent -- > :<|> "b" :> Capture "x" Int :> Get '[JSON] Bool -- > :<|> "c" :> Put '[JSON] Bool -- > :<|> "a" :> "e" :> Get '[JSON] Int @@ -186,12 +189,12 @@ -- that one takes precedence. If both parts fail, the \"better\" error -- code will be returned. -- -layout :: (HasServer layout '[]) => Proxy layout -> Text +layout :: (HasServer api '[]) => Proxy api -> Text layout p = layoutWithContext p EmptyContext -- | Variant of 'layout' that takes an additional 'Context'. -layoutWithContext :: (HasServer layout context) - => Proxy layout -> Context context -> Text +layoutWithContext :: (HasServer api context) + => Proxy api -> Context context -> Text layoutWithContext p context = routerLayout (route p context (emptyDelayed (FailFatal err501))) diff --git a/src/Servant/Server/Internal.hs b/src/Servant/Server/Internal.hs --- a/src/Servant/Server/Internal.hs +++ b/src/Servant/Server/Internal.hs @@ -68,16 +68,16 @@ import Servant.Server.Internal.ServantErr -class HasServer layout context where - type ServerT layout (m :: * -> *) :: * +class HasServer api context where + type ServerT api (m :: * -> *) :: * route :: - Proxy layout + Proxy api -> Context context - -> Delayed env (Server layout) + -> Delayed env (Server api) -> Router env -type Server layout = ServerT layout Handler +type Server api = ServerT api Handler -- * Instances @@ -118,15 +118,15 @@ -- > server = getBook -- > where getBook :: Text -> Handler Book -- > getBook isbn = ... -instance (KnownSymbol capture, FromHttpApiData a, HasServer sublayout context) - => HasServer (Capture capture a :> sublayout) context where +instance (KnownSymbol capture, FromHttpApiData a, HasServer api context) + => HasServer (Capture capture a :> api) context where - type ServerT (Capture capture a :> sublayout) m = - a -> ServerT sublayout m + type ServerT (Capture capture a :> api) m = + a -> ServerT api m route Proxy context d = CaptureRouter $ - route (Proxy :: Proxy sublayout) + route (Proxy :: Proxy api) context (addCapture d $ \ txt -> case parseUrlPieceMaybe txt :: Maybe a of Nothing -> delayedFail err400 @@ -236,15 +236,15 @@ -- > server = viewReferer -- > where viewReferer :: Referer -> Handler referer -- > viewReferer referer = return referer -instance (KnownSymbol sym, FromHttpApiData a, HasServer sublayout context) - => HasServer (Header sym a :> sublayout) context where +instance (KnownSymbol sym, FromHttpApiData a, HasServer api context) + => HasServer (Header sym a :> api) context where - type ServerT (Header sym a :> sublayout) m = - Maybe a -> ServerT sublayout m + type ServerT (Header sym a :> api) m = + Maybe a -> ServerT api m route Proxy context subserver = let mheader req = parseHeaderMaybe =<< lookup str (requestHeaders req) - in route (Proxy :: Proxy sublayout) context (passToServer subserver mheader) + in route (Proxy :: Proxy api) context (passToServer subserver mheader) where str = fromString $ symbolVal (Proxy :: Proxy sym) -- | If you use @'QueryParam' "author" Text@ in one of the endpoints for your API, @@ -268,11 +268,11 @@ -- > where getBooksBy :: Maybe Text -> Handler [Book] -- > getBooksBy Nothing = ...return all books... -- > getBooksBy (Just author) = ...return books by the given author... -instance (KnownSymbol sym, FromHttpApiData a, HasServer sublayout context) - => HasServer (QueryParam sym a :> sublayout) context where +instance (KnownSymbol sym, FromHttpApiData a, HasServer api context) + => HasServer (QueryParam sym a :> api) context where - type ServerT (QueryParam sym a :> sublayout) m = - Maybe a -> ServerT sublayout m + type ServerT (QueryParam sym a :> api) m = + Maybe a -> ServerT api m route Proxy context subserver = let querytext r = parseQueryText $ rawQueryString r @@ -282,7 +282,7 @@ Just Nothing -> Nothing -- param present with no value -> Nothing Just (Just v) -> parseQueryParamMaybe v -- if present, we try to convert to -- the right type - in route (Proxy :: Proxy sublayout) context (passToServer subserver param) + in route (Proxy :: Proxy api) context (passToServer subserver param) where paramname = cs $ symbolVal (Proxy :: Proxy sym) -- | If you use @'QueryParams' "authors" Text@ in one of the endpoints for your API, @@ -304,11 +304,11 @@ -- > server = getBooksBy -- > where getBooksBy :: [Text] -> Handler [Book] -- > getBooksBy authors = ...return all books by these authors... -instance (KnownSymbol sym, FromHttpApiData a, HasServer sublayout context) - => HasServer (QueryParams sym a :> sublayout) context where +instance (KnownSymbol sym, FromHttpApiData a, HasServer api context) + => HasServer (QueryParams sym a :> api) context where - type ServerT (QueryParams sym a :> sublayout) m = - [a] -> ServerT sublayout m + type ServerT (QueryParams sym a :> api) m = + [a] -> ServerT api m route Proxy context subserver = let querytext r = parseQueryText $ rawQueryString r @@ -317,7 +317,7 @@ -- corresponding values parameters r = filter looksLikeParam (querytext r) values r = mapMaybe (convert . snd) (parameters r) - in route (Proxy :: Proxy sublayout) context (passToServer subserver values) + in route (Proxy :: Proxy api) context (passToServer subserver values) where paramname = cs $ symbolVal (Proxy :: Proxy sym) looksLikeParam (name, _) = name == paramname || name == (paramname <> "[]") convert Nothing = Nothing @@ -335,11 +335,11 @@ -- > server = getBooks -- > where getBooks :: Bool -> Handler [Book] -- > getBooks onlyPublished = ...return all books, or only the ones that are already published, depending on the argument... -instance (KnownSymbol sym, HasServer sublayout context) - => HasServer (QueryFlag sym :> sublayout) context where +instance (KnownSymbol sym, HasServer api context) + => HasServer (QueryFlag sym :> api) context where - type ServerT (QueryFlag sym :> sublayout) m = - Bool -> ServerT sublayout m + type ServerT (QueryFlag sym :> api) m = + Bool -> ServerT api m route Proxy context subserver = let querytext r = parseQueryText $ rawQueryString r @@ -347,7 +347,7 @@ Just Nothing -> True -- param is there, with no value Just (Just v) -> examine v -- param with a value Nothing -> False -- param not in the query string - in route (Proxy :: Proxy sublayout) context (passToServer subserver param) + in route (Proxy :: Proxy api) context (passToServer subserver param) where paramname = cs $ symbolVal (Proxy :: Proxy sym) examine v | v == "true" || v == "1" || v == "" = True | otherwise = False @@ -392,14 +392,14 @@ -- > server = postBook -- > where postBook :: Book -> Handler Book -- > postBook book = ...insert into your db... -instance ( AllCTUnrender list a, HasServer sublayout context - ) => HasServer (ReqBody list a :> sublayout) context where +instance ( AllCTUnrender list a, HasServer api context + ) => HasServer (ReqBody list a :> api) context where - type ServerT (ReqBody list a :> sublayout) m = - a -> ServerT sublayout m + type ServerT (ReqBody list a :> api) m = + a -> ServerT api m route Proxy context subserver = - route (Proxy :: Proxy sublayout) context (addBodyCheck subserver bodyCheck) + route (Proxy :: Proxy api) context (addBodyCheck subserver bodyCheck) where bodyCheck = withRequest $ \ request -> do -- See HTTP RFC 2616, section 7.2.1 @@ -416,15 +416,15 @@ Just (Right v) -> return v -- | Make sure the incoming request starts with @"/path"@, strip it and --- pass the rest of the request path to @sublayout@. -instance (KnownSymbol path, HasServer sublayout context) => HasServer (path :> sublayout) context where +-- pass the rest of the request path to @api@. +instance (KnownSymbol path, HasServer api context) => HasServer (path :> api) context where - type ServerT (path :> sublayout) m = ServerT sublayout m + type ServerT (path :> api) m = ServerT api m route Proxy context subserver = pathRouter (cs (symbolVal proxyPath)) - (route (Proxy :: Proxy sublayout) context subserver) + (route (Proxy :: Proxy api) context subserver) where proxyPath = Proxy :: Proxy path instance HasServer api context => HasServer (RemoteHost :> api) context where diff --git a/src/Servant/Server/Internal/ServantErr.hs b/src/Servant/Server/Internal/ServantErr.hs --- a/src/Servant/Server/Internal/ServantErr.hs +++ b/src/Servant/Server/Internal/ServantErr.hs @@ -31,7 +31,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err300 { errBody = "I can't choose." } +-- > failingHandler = throwError $ err300 { errBody = "I can't choose." } -- err300 :: ServantErr err300 = ServantErr { errHTTPCode = 300 @@ -45,7 +45,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr err301 +-- > failingHandler = throwError err301 -- err301 :: ServantErr err301 = ServantErr { errHTTPCode = 301 @@ -59,7 +59,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr err302 +-- > failingHandler = throwError err302 -- err302 :: ServantErr err302 = ServantErr { errHTTPCode = 302 @@ -73,7 +73,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr err303 +-- > failingHandler = throwError err303 -- err303 :: ServantErr err303 = ServantErr { errHTTPCode = 303 @@ -87,7 +87,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr err304 +-- > failingHandler = throwError err304 -- err304 :: ServantErr err304 = ServantErr { errHTTPCode = 304 @@ -101,7 +101,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr err305 +-- > failingHandler = throwError err305 -- err305 :: ServantErr err305 = ServantErr { errHTTPCode = 305 @@ -115,7 +115,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr err307 +-- > failingHandler = throwError err307 -- err307 :: ServantErr err307 = ServantErr { errHTTPCode = 307 @@ -129,7 +129,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err400 { errBody = "Your request makes no sense to me." } +-- > failingHandler = throwError $ err400 { errBody = "Your request makes no sense to me." } -- err400 :: ServantErr err400 = ServantErr { errHTTPCode = 400 @@ -143,7 +143,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err401 { errBody = "Your credentials are invalid." } +-- > failingHandler = throwError $ err401 { errBody = "Your credentials are invalid." } -- err401 :: ServantErr err401 = ServantErr { errHTTPCode = 401 @@ -157,7 +157,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err402 { errBody = "You have 0 credits. Please give me $$$." } +-- > failingHandler = throwError $ err402 { errBody = "You have 0 credits. Please give me $$$." } -- err402 :: ServantErr err402 = ServantErr { errHTTPCode = 402 @@ -171,7 +171,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err403 { errBody = "Please login first." } +-- > failingHandler = throwError $ err403 { errBody = "Please login first." } -- err403 :: ServantErr err403 = ServantErr { errHTTPCode = 403 @@ -185,7 +185,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err404 { errBody = "(╯°□°）╯︵ ┻━┻)." } +-- > failingHandler = throwError $ err404 { errBody = "(╯°□°）╯︵ ┻━┻)." } -- err404 :: ServantErr err404 = ServantErr { errHTTPCode = 404 @@ -199,7 +199,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err405 { errBody = "Your account privileges does not allow for this. Please pay $$$." } +-- > failingHandler = throwError $ err405 { errBody = "Your account privileges does not allow for this. Please pay $$$." } -- err405 :: ServantErr err405 = ServantErr { errHTTPCode = 405 @@ -213,7 +213,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr err406 +-- > failingHandler = throwError err406 -- err406 :: ServantErr err406 = ServantErr { errHTTPCode = 406 @@ -227,7 +227,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr err407 +-- > failingHandler = throwError err407 -- err407 :: ServantErr err407 = ServantErr { errHTTPCode = 407 @@ -241,7 +241,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err409 { errBody = "Transaction conflicts with 59879cb56c7c159231eeacdd503d755f7e835f74" } +-- > failingHandler = throwError $ err409 { errBody = "Transaction conflicts with 59879cb56c7c159231eeacdd503d755f7e835f74" } -- err409 :: ServantErr err409 = ServantErr { errHTTPCode = 409 @@ -255,7 +255,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err410 { errBody = "I know it was here at some point, but.. I blame bad luck." } +-- > failingHandler = throwError $ err410 { errBody = "I know it was here at some point, but.. I blame bad luck." } -- err410 :: ServantErr err410 = ServantErr { errHTTPCode = 410 @@ -269,7 +269,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr err411 +-- > failingHandler = throwError err411 -- err411 :: ServantErr err411 = ServantErr { errHTTPCode = 411 @@ -283,7 +283,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err412 { errBody = "Precondition fail: x < 42 && y > 57" } +-- > failingHandler = throwError $ err412 { errBody = "Precondition fail: x < 42 && y > 57" } -- err412 :: ServantErr err412 = ServantErr { errHTTPCode = 412 @@ -297,7 +297,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err413 { errBody = "Request exceeded 64k." } +-- > failingHandler = throwError $ err413 { errBody = "Request exceeded 64k." } -- err413 :: ServantErr err413 = ServantErr { errHTTPCode = 413 @@ -311,7 +311,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err414 { errBody = "Maximum length is 64." } +-- > failingHandler = throwError $ err414 { errBody = "Maximum length is 64." } -- err414 :: ServantErr err414 = ServantErr { errHTTPCode = 414 @@ -325,7 +325,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err415 { errBody = "Supported media types: gif, png" } +-- > failingHandler = throwError $ err415 { errBody = "Supported media types: gif, png" } -- err415 :: ServantErr err415 = ServantErr { errHTTPCode = 415 @@ -339,7 +339,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err416 { errBody = "Valid range is [0, 424242]." } +-- > failingHandler = throwError $ err416 { errBody = "Valid range is [0, 424242]." } -- err416 :: ServantErr err416 = ServantErr { errHTTPCode = 416 @@ -353,7 +353,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err417 { errBody = "I found a quux in the request. This isn't going to work." } +-- > failingHandler = throwError $ err417 { errBody = "I found a quux in the request. This isn't going to work." } -- err417 :: ServantErr err417 = ServantErr { errHTTPCode = 417 @@ -367,7 +367,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err500 { errBody = "Exception in module A.B.C:55. Have a great day!" } +-- > failingHandler = throwError $ err500 { errBody = "Exception in module A.B.C:55. Have a great day!" } -- err500 :: ServantErr err500 = ServantErr { errHTTPCode = 500 @@ -381,7 +381,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err501 { errBody = "/v1/foo is not supported with quux in the request." } +-- > failingHandler = throwError $ err501 { errBody = "/v1/foo is not supported with quux in the request." } -- err501 :: ServantErr err501 = ServantErr { errHTTPCode = 501 @@ -395,7 +395,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err502 { errBody = "Tried gateway foo, bar, and baz. None responded." } +-- > failingHandler = throwError $ err502 { errBody = "Tried gateway foo, bar, and baz. None responded." } -- err502 :: ServantErr err502 = ServantErr { errHTTPCode = 502 @@ -409,7 +409,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err503 { errBody = "We're rewriting in PHP." } +-- > failingHandler = throwError $ err503 { errBody = "We're rewriting in PHP." } -- err503 :: ServantErr err503 = ServantErr { errHTTPCode = 503 @@ -423,7 +423,7 @@ -- Example: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err504 { errBody = "Backend foobar did not respond in 5 seconds." } +-- > failingHandler = throwError $ err504 { errBody = "Backend foobar did not respond in 5 seconds." } -- err504 :: ServantErr err504 = ServantErr { errHTTPCode = 504 @@ -437,7 +437,7 @@ -- Example usage: -- -- > failingHandler :: Handler () --- > failingHandler = throwErr $ err505 { errBody = "I support HTTP/4.0 only." } +-- > failingHandler = throwError $ err505 { errBody = "I support HTTP/4.0 only." } -- err505 :: ServantErr err505 = ServantErr { errHTTPCode = 505 diff --git a/test/Servant/Server/RouterSpec.hs b/test/Servant/Server/RouterSpec.hs --- a/test/Servant/Server/RouterSpec.hs +++ b/test/Servant/Server/RouterSpec.hs @@ -8,7 +8,7 @@ import Data.Proxy (Proxy(..)) import Data.Text (unpack) import Network.HTTP.Types (Status (..)) -import Network.Wai (Application, responseBuilder) +import Network.Wai (responseBuilder) import Network.Wai.Internal (Response (ResponseBuilder)) import Test.Hspec import Test.Hspec.Wai (get, shouldRespondWith, with) @@ -74,7 +74,7 @@ makeTrivialRouter p = route p EmptyContext (emptyDelayed (FailFatal err501)) -type End = Get '[JSON] () +type End = Get '[JSON] NoContent -- The latter version looks more efficient, -- but the former should be compiled to the diff --git a/test/Servant/ServerSpec.hs b/test/Servant/ServerSpec.hs --- a/test/Servant/ServerSpec.hs +++ b/test/Servant/ServerSpec.hs @@ -340,19 +340,23 @@ -- * headerSpec {{{ ------------------------------------------------------------------------------ -type HeaderApi a = Header "MyHeader" a :> Delete '[JSON] () +type HeaderApi a = Header "MyHeader" a :> Delete '[JSON] NoContent headerApi :: Proxy (HeaderApi a) headerApi = Proxy headerSpec :: Spec headerSpec = describe "Servant.API.Header" $ do - let expectsInt :: Maybe Int -> Handler () - expectsInt (Just x) = when (x /= 5) $ error "Expected 5" + let expectsInt :: Maybe Int -> Handler NoContent + expectsInt (Just x) = do + when (x /= 5) $ error "Expected 5" + return NoContent expectsInt Nothing = error "Expected an int" - let expectsString :: Maybe String -> Handler () - expectsString (Just x) = when (x /= "more from you") $ error "Expected more from you" + let expectsString :: Maybe String -> Handler NoContent + expectsString (Just x) = do + when (x /= "more from you") $ error "Expected more from you" + return NoContent expectsString Nothing = error "Expected a string" with (return (serve headerApi expectsInt)) $ do @@ -410,7 +414,7 @@ :<|> "foo" :> Get '[PlainText] T.Text :<|> "bar" :> Post '[JSON] Animal :<|> "bar" :> Put '[JSON] Animal - :<|> "bar" :> Delete '[JSON] () + :<|> "bar" :> Delete '[JSON] NoContent alternativeApi :: Proxy AlternativeApi alternativeApi = Proxy @@ -422,7 +426,7 @@ :<|> return "a string" :<|> return jerry :<|> return jerry - :<|> return () + :<|> return NoContent alternativeSpec :: Spec alternativeSpec = do