Safe Haskell | Safe |
---|---|
Language | Haskell2010 |
Synopsis
- captureProcessResult :: IO () -> IO ProcessResult
- data ProcessResult = ProcessResult {
- prStdout :: !ByteString
- prStderr :: !ByteString
- prExitCode :: !ExitCode
- prException :: !(Maybe SomeException)
- withStdin :: ByteString -> IO a -> IO a
- withEnv :: [(String, Maybe String)] -> IO a -> IO a
- withArgs :: [String] -> IO a -> IO a
- data ExitCode
Utilities for testing your main function
captureProcessResult :: IO () -> IO ProcessResult Source #
Capture stdout, stderr, and exit code of the given IO action.
>>>
let main = putStr "hello"
>>>
captureProcessResult main
ProcessResult {prStdout = "hello", prStderr = "", prExitCode = ExitSuccess, prException = Nothing}
If the IO action exit with error message, the exit code of result is ExitFailure
.
>>>
import System.IO
>>>
import System.Exit
>>>
let main = hPutStr stderr "OMG!" >> exitWith (ExitFailure 1)
>>>
captureProcessResult main
ProcessResult {prStdout = "", prStderr = "OMG!", prExitCode = ExitFailure 1, prException = Nothing}
Since v0.2.0.0, this function catches SomeException
, not only ExitCode
to prevent it from losing output when an exception other than ExitCode
is thrown.
To get the thrown error, use prException
.
Note: prStderr
doesn't contain the error message of the thrown exception.
See the example below.
>>>
import Control.Exception
>>>
let main = ioError $ userError "OMG!"
>>>
captureProcessResult main
ProcessResult {prStdout = "", prStderr = "", prExitCode = ExitFailure 1, prException = Just user error (OMG!)}
Since: main-tester-0.2.0.0
data ProcessResult Source #
Used for the result of captureProcessResult
.
ProcessResult | |
|
Instances
withStdin :: ByteString -> IO a -> IO a Source #
Pass the ByteString to stdin of the given IO action.
>>>
import Data.ByteString.Char8 ()
>>>
:set -XOverloadedStrings
>>>
let main = putStrLn . reverse =<< getLine
>>>
withStdin "abcde" main
edcba
withEnv :: [(String, Maybe String)] -> IO a -> IO a Source #
Run the given IO action with the specified environment variables set.
The environment variables are specified as pairs of ENV_VAR_NAME
and ENV_VAR_VALUE
.
If ENV_VAR_VALUE
is Nothing
, the ENV_VAR_NAME
is unset with unsetEnv
.
>>>
import System.Environment
>>>
setEnv "ENV_VAR_TO_UNSET" "value_to_unset"
>>>
setEnv "ENV_VAR_TO_OVERWRITE" "value_to_overwrite"
>>>
let main = (print =<< lookupEnv "ENV_VAR_TO_UNSET") >> (print =<< lookupEnv "ENV_VAR_TO_OVERWRITE")
>>>
withEnv [("ENV_VAR_TO_UNSET", Nothing), ("ENV_VAR_TO_OVERWRITE" , Just "new_value")] main
Nothing Just "new_value">>>
main
Just "value_to_unset" Just "value_to_overwrite"
Re-export from System.Environment
Re-export from System.Exit
Defines the exit codes that a program can return.
ExitSuccess | indicates successful termination; |
ExitFailure Int | indicates program failure with an exit code. The exact interpretation of the code is operating-system dependent. In particular, some values may be prohibited (e.g. 0 on a POSIX-compliant system). |
Instances
Eq ExitCode | |
Ord ExitCode | |
Defined in GHC.IO.Exception | |
Read ExitCode | |
Show ExitCode | |
Generic ExitCode | |
Exception ExitCode | Since: base-4.1.0.0 |
Defined in GHC.IO.Exception toException :: ExitCode -> SomeException # fromException :: SomeException -> Maybe ExitCode # displayException :: ExitCode -> String # | |
type Rep ExitCode | |
Defined in GHC.IO.Exception |