Safe Haskell | Safe-Infered |
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Introductory documentation: https://github.com/sol/test-shouldbe#readme
- shouldBe :: (Show a, Eq a) => a -> a -> Assertion
- shouldSatisfy :: Show a => a -> (a -> Bool) -> Assertion
- shouldThrow :: Exception e => IO a -> Selector e -> Assertion
- type Selector a = a -> Bool
- anyException :: Selector SomeException
- anyErrorCall :: Selector ErrorCall
- anyIOException :: Selector IOException
- anyArithException :: Selector ArithException
- errorCall :: String -> Selector ErrorCall
Making assertions
shouldBe :: (Show a, Eq a) => a -> a -> AssertionSource
actual `shouldBe` expected
asserts that actual
is equal to expected
(this is just an alias for @?=
).
shouldSatisfy :: Show a => a -> (a -> Bool) -> AssertionSource
v `shouldSatisfy` p
asserts that p v
is True
.
Checking for exceptions
shouldThrow :: Exception e => IO a -> Selector e -> AssertionSource
action `shouldThrow` selector
asserts that action
throws an exception.
The precise nature of that exception is described with a Selector
.
Selecting exceptions
type Selector a = a -> BoolSource
A Selector
is a predicate; it can simultaneously constrain the type and
value of an exception.
Predefined type-based selectors
There are predefined selectors for some standard exceptions. Each selector
is just const True
with an appropriate type.
Combinators for defining value-based selectors
Some exceptions (most prominently ErrorCall
) have no Eq
instance.
Selecting a specific value would require pattern matching.
For such exceptions, combinators that construct selectors are provided. Each combinator corresponds to a constructor; it takes the same arguments, and has the same name (but starting with a lower-case letter).