Modulechell-0.5.0.2GHC2021

Test.Chell

Chell is a simple and intuitive library for automated testing. It natively supports assertion-based testing, and can use companion libraries such as chell-quickcheck to support more complex testing strategies.

An example test suite, which verifies the behavior of arithmetic operators.

{-# LANGUAGE TemplateHaskell #-}

import Test.Chell

suite_Math :: Suite
suite_Math = suite "math"
   [ test_Addition
   , test_Subtraction
   ]

test_Addition :: Test
test_Addition = assertions "addition" $ do
   $expect (equal (2 + 1) 3)
   $expect (equal (1 + 2) 3)

test_Subtraction :: Test
test_Subtraction = assertions "subtraction" $ do
   $expect (equal (2 - 1) 1)
   $expect (equal (1 - 2) (-1))

main :: IO ()
main = defaultMain [suite_Math]

$ ghc --make chell-example.hs
$ ./chell-example
PASS: 2 tests run, 2 tests passed

8 types
3 classes
47 values

Packagechell-0.5.0.2
Exports58
LanguageGHC2021
LicenceMIT
SourceChell.hs

Main

1 declaration

valuedefaultMain :: [Suite] -> IO ()

A simple default main function, which runs a list of tests and logs statistics to stdout.

Test suites

4 declarations

datadata Suite

A suite is a named collection of tests.

Note: earlier versions of Chell permitted arbitrary nesting of test suites. This feature proved too unwieldy, and was removed. A similar result can be achieved with suiteTests; see the documentation for suite.

Instances2Show, SuiteOrTest

Show SuiteDefined in chell-0.5.0.2 · Test.Chell.Types
SuiteOrTest SuiteDefined in chell-0.5.0.2 · Test.Chell.Types

valuesuite :: String -> [Test] -> Suite

Define a new Suite, with the given name and children.

Note: earlier versions of Chell permitted arbitrary nesting of test suites. This feature proved too unwieldy, and was removed. A similar result can be achieved with suiteTests:

test_Addition :: Test
test_Subtraction :: Test
test_Show :: Test

suite_Math :: Suite
suite_Math = suite "math"
   [ test_Addition
   , test_Subtraction
   ]

suite_Prelude :: Suite
suite_Prelude = suite "prelude"
   (
     [ test_Show
     ]
     ++ suiteTests suite_Math
   )

valuesuiteName :: Suite -> String

Get a suite's name. Suite names may be any string, but are typically plain ASCII so users can easily type them on the command line.

$ ghci chell-example.hs
Ok, modules loaded: Main.

*Main> suiteName tests_Math
"math"

valuesuiteTests :: Suite -> [Test]

Get the full list of tests contained within this Suite. Each test is given its full name within the test hierarchy, where names are separated by periods.

$ ghci chell-example.hs
Ok, modules loaded: Main.

*Main> suiteTests tests_Math
[Test "math.addition",Test "math.subtraction"]

Skipping some tests

classclass SuiteOrTest a where

Instances2SuiteOrTest

SuiteOrTest SuiteDefined in chell-0.5.0.2 · Test.Chell.Types
SuiteOrTest TestDefined in chell-0.5.0.2 · Test.Chell.Types

valueskipIf :: SuiteOrTest a => Bool -> a -> a

Conditionally skip tests. Use this to avoid commenting out tests which are currently broken, or do not work on the current platform.

tests :: Suite
tests = suite "tests"
   [ test_Foo
   , skipIf builtOnUnix test_WindowsSpecific
   , test_Bar
   ]

valueskipWhen :: SuiteOrTest a => IO Bool -> a -> a

Conditionally skip tests, depending on the result of a runtime check. The predicate is checked before each test is started.

tests :: Suite
tests = suite "tests"
   [ test_Foo
   , skipWhen noNetwork test_PingGoogle
   , test_Bar
   ]

Basic testing library

14 declarations

newtypenewtype Assertions a

See assertions.

Instances4Monad, Functor, Applicative, MonadIO

Monad AssertionsDefined in chell-0.5.0.2 · Test.Chell
Functor AssertionsDefined in chell-0.5.0.2 · Test.Chell
Applicative AssertionsDefined in chell-0.5.0.2 · Test.Chell
MonadIO AssertionsDefined in chell-0.5.0.2 · Test.Chell

valueassertions :: String -> Assertions a -> Test

Convert a sequence of pass/fail assertions into a runnable test.

test_Equality :: Test
test_Equality = assertions "equality" $ do
    $assert (1 == 1)
    $assert (equal 1 1)

classclass IsAssertion a where

See assert and expect.

Instances3IsAssertion

IsAssertion AssertionDefined in chell-0.5.0.2 · Test.Chell
IsAssertion BoolDefined in chell-0.5.0.2 · Test.Chell
IsAssertion a => IsAssertion (IO a)Defined in chell-0.5.0.2 · Test.Chell

datadata Assertion

A single pass/fail assertion. Failed assertions include an explanatory message.

Instances3Eq, Show, IsAssertion

Eq AssertionDefined in chell-0.5.0.2 · Test.Chell
Show AssertionDefined in chell-0.5.0.2 · Test.Chell
IsAssertion AssertionDefined in chell-0.5.0.2 · Test.Chell

valueassertionPassed :: Assertion

See Assertion.

valueassertionFailed :: String -> Assertion

See Assertion.

valueassert :: Q Exp

valueexpect :: Q Exp

valuedie :: Q Exp

valuetrace :: Q Exp

valuenote :: String -> String -> Assertions ()

Attach a note to a test run. Notes will be printed to stdout and included in reports, even if the test fails or aborts. Notes are useful for debugging failing tests.

valueafterTest :: IO () -> Assertions ()

valuerequireLeft :: Q Exp

valuerequireRight :: Q Exp

Built-in assertions

valueequal :: (Show a, Eq a) => a -> a -> Assertion

Assert that two values are equal.

valuenotEqual :: (Eq a, Show a) => a -> a -> Assertion

Assert that two values are not equal.

valueequalWithin

:: (Real a, Show a)
=> a
-> a
-> a
delta
-> Assertion

Assert that two values are within some delta of each other.

valuejust :: Maybe a -> Assertion

Assert that some value is Just.

valuenothing :: Show a => Maybe a -> Assertion

Assert that some value is Nothing.

valueleft :: Show b => Either a b -> Assertion

Assert that some value is Left.

valueright :: Show a => Either a b -> Assertion

Assert that some value is Right.

valuethrows :: Exception err => (err -> Bool) -> IO a -> IO Assertion

Assert that some computation throws an exception matching the provided predicate. This is mostly useful for exception types which do not have an instance for Eq, such as ErrorCall.

valuethrowsEq :: (Eq err, Exception err, Show err) => err -> IO a -> IO Assertion

Assert that some computation throws an exception equal to the given exception. This is better than just checking that the correct type was thrown, because the test can also verify the exception contains the correct information.

valuegreater :: (Ord a, Show a) => a -> a -> Assertion

Assert a value is greater than another.

valuegreaterEqual :: (Ord a, Show a) => a -> a -> Assertion

Assert a value is greater than or equal to another.

valuelesser :: (Ord a, Show a) => a -> a -> Assertion

Assert a value is less than another.

valuelesserEqual :: (Ord a, Show a) => a -> a -> Assertion

Assert a value is less than or equal to another.

valuesameItems

:: (Foldable container, Show item, Ord item)
=> container item
-> container item
-> Assertion

Assert that two containers have the same items, in any order.

valueequalItems

:: (Foldable container, Show item, Ord item)
=> container item
-> container item
-> Assertion

Assert that two containers have the same items, in the same order.

classclass IsText a where

Class for types which can be treated as text; see equalLines.

Instances5IsText

IsText ByteStringDefined in chell-0.5.0.2 · Test.Chell
Uses Data.ByteString.Char8
IsText ByteStringDefined in chell-0.5.0.2 · Test.Chell
Uses Data.ByteString.Lazy.Char8
IsText StringDefined in chell-0.5.0.2 · Test.Chell
IsText TextDefined in chell-0.5.0.2 · Test.Chell
IsText TextDefined in chell-0.5.0.2 · Test.Chell

valueequalLines :: (Ord a, IsText a) => a -> a -> Assertion

Assert that two pieces of text are equal. This uses a diff algorithm to check line-by-line, so the error message will be easier to read on large inputs.

valueequalLinesWith :: Ord a => (a -> [String]) -> a -> a -> Assertion

Variant of equalLines which allows a user-specified line-splitting predicate.

Custom test types

4 declarations

datadata Test

A Test is, essentially, an IO action that returns a TestResult. Tests are aggregated into suites (see Suite).

Instances2Show, SuiteOrTest

Show TestDefined in chell-0.5.0.2 · Test.Chell.Types
SuiteOrTest TestDefined in chell-0.5.0.2 · Test.Chell.Types

valuetest :: String -> (TestOptions -> IO TestResult) -> Test

Define a test, with the given name and implementation.

valuetestName :: Test -> String

Get the name a test was given when it was defined; see test.

valuerunTest :: Test -> TestOptions -> IO TestResult

Run a test, wrapped in error handlers. This will return TestAborted if the test throws an exception or times out.

Test results

datadata TestResult

The result of running a test.

To support future extensions to the testing API, any users of this module who pattern-match against the TestResult constructors should include a default case. If no default case is provided, a warning will be issued.

Constructors

TestPassed [(String, String)]
The test passed, and generated the given notes.
TestSkipped
The test did not run, because it was skipped with skipIf or skipWhen.
TestFailed [(String, String)] [Failure]
The test failed, generating the given notes and failures.
TestAborted [(String, String)] String
The test aborted with an error message, and generated the given notes.

Instances2Eq, Show

Eq TestResultDefined in chell-0.5.0.2 · Test.Chell.Types
Show TestResultDefined in chell-0.5.0.2 · Test.Chell.Types

Failures

datadata Failure

Contains details about a test failure.

Instances2Eq, Show

Eq FailureDefined in chell-0.5.0.2 · Test.Chell.Types
Show FailureDefined in chell-0.5.0.2 · Test.Chell.Types

valuefailure :: Failure

An empty Failure; use the field accessors to populate this value.

valuefailureLocation :: Failure -> Maybe Location

If given, the location of the failing assertion, expectation, etc.

failureLocation is a field accessor, and can be used to update a Failure value.

valuefailureMessage :: Failure -> String

If given, a message which explains why the test failed.

failureMessage is a field accessor, and can be used to update a Failure value.

Failure locations

datadata Location

Contains details about a location in the test source file.

Instances2Eq, Show

Eq LocationDefined in chell-0.5.0.2 · Test.Chell.Types
Show LocationDefined in chell-0.5.0.2 · Test.Chell.Types

valuelocation :: Location

An empty Location; use the field accessors to populate this value.

valuelocationFile :: Location -> String

A path to a source file, or empty if not provided.

locationFile is a field accessor, and can be used to update a Location value.

valuelocationModule :: Location -> String

A Haskell module name, or empty if not provided.

locationModule is a field accessor, and can be used to update a Location value.

valuelocationLine :: Location -> Maybe Integer

A line number, or Nothing if not provided.

locationLine is a field accessor, and can be used to update a Location value.

Test options

datadata TestOptions

Test options are passed to each test, and control details about how the test should be run.

Instances2Eq, Show

Eq TestOptionsDefined in chell-0.5.0.2 · Test.Chell.Types
Show TestOptionsDefined in chell-0.5.0.2 · Test.Chell.Types

valuedefaultTestOptions :: TestOptions

Default test options.

$ ghci
Prelude> import Test.Chell

Test.Chell> testOptionSeed defaultTestOptions
0

Test.Chell> testOptionTimeout defaultTestOptions
Nothing

valuetestOptionSeed :: TestOptions -> Int

Get the RNG seed for this test run. The seed is generated once, in defaultMain, and used for all tests. It is also logged to reports using a note.

When using defaultMain, users may specify a seed using the --seed command-line option.

testOptionSeed is a field accessor, and can be used to update a TestOptions value.

valuetestOptionTimeout :: TestOptions -> Maybe Int

An optional timeout, in milliseconds. Tests which run longer than this timeout will be aborted.

When using defaultMain, users may specify a timeout using the --timeout command-line option.

testOptionTimeout is a field accessor, and can be used to update a TestOptions value.