Test.Hspec

Hspec is a testing framework for Haskell.

This is the library reference for Hspec. The User's Manual contains more in-depth documentation.

Types

type Spec = SpecM ()

class Example a

A type class for examples.

Instances

Example Bool

Example Property

Example Expectation

Example Result

Setting expectations

module Test.Hspec.Expectations

Defining a spec

describe :: String -> Spec -> Spec

Combine a list of specs into a larger spec.

context :: String -> Spec -> Spec

An alias for describe.

it :: Example a => String -> a -> Spec

Create a spec item.

A spec item consists of:

• a textual description of a desired behavior
• an example for that behavior

 describe "absolute" $ do
   it "returns a positive number when given a negative number" $
     absolute (-1) == 1

specify :: Example a => String -> a -> Spec

An alias for it.

example :: Expectation -> Expectation

This is a type restricted version of id. It can be used to get better error messages on type mismatches.

Compare e.g.

 it "exposes some behavior" $ example $ do
   putStrLn

with

 it "exposes some behavior" $ do
   putStrLn

pending :: Expectation

Specifies a pending example.

If you want to textually specify a behavior but do not have an example yet, use this:

 describe "fancyFormatter" $ do
   it "can format text in a way that everyone likes" $
     pending

pendingWith :: String -> Expectation

Specifies a pending example with a reason for why it's pending.

 describe "fancyFormatter" $ do
   it "can format text in a way that everyone likes" $
     pendingWith "waiting for clarification from the designers"

before :: IO () -> Spec -> Spec

Run a custom action before every spec item.

beforeAll :: IO () -> Spec -> Spec

Run a custom action before all spec items.

after :: IO () -> Spec -> Spec

Run a custom action after every spec item.

around :: (IO () -> IO ()) -> Spec -> Spec

Run a custom action before and/or after every spec item.

parallel :: Spec -> Spec

Run examples of given spec in parallel.

runIO :: IO a -> SpecM a

Run an IO action while constructing the spec tree.

SpecM is a monad to construct a spec tree, without executing any spec items. runIO allows you to run IO actions during this construction phase. The IO action is always run when the spec tree is constructed (e.g. even when --dry-run is specified).

Running a spec

hspec :: Spec -> IO ()

Run given spec and write a report to stdout. Exit with exitFailure if at least one spec item fails.