bdd.gby

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1 Haskell Behavior Driven Development 1

2 Haskell 4 Mew Firemacs Mighty ghc-mod 2

3 Ruby/Java HackageDB 3

4 Haskeller 4

5 Haskeller 5

6 Q) Haskeller A) 6

7 7

8 Haskeller Haskell 8

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10 10

11 Haskell 11

12 Haskell Haskell 12

13 13

14 Haskell 14

15 Haskell 15

16 Haskell 16

17 \^^/ 17

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19 19

20 Haskeller HUnit QuickCheck 20

21 QuickCheck prop_doublesort :: [Int] -> Bool prop_doublesort xs = sort xs == sort (sort xs) > quickcheck prop_doublesort +++ OK, passed 100 tests. 21

22 22

23 Haskell QuickCheck sort :: Ord a => [a] -> [a] lookup :: Eq a => a -> [(a, b)] -> Maybe b delete :: Eq a => a -> [a] -> [a] HUnit ( ) hgetline :: Handle -> IO String writefile :: FilePath -> String -> IO () forkio :: IO () -> IO ThreadId 23

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26 26

27 QuickCheck QuickCheck prop_model x xs = linearsearch x xs == binarysearch x xs 27

28 QuickCheck 28

29 Haskeller 29

30 Simon HENGEL doctest 30

31 doctest Python def factorial(n): """Return the factorial of n, an exact integer >= 0. If the result is small enough to fit in an int, return an int. Else return a long. >>> [factorial(n) for n in range(6)] [1, 1, 2, 6, 24, 120] >>> factorial(30) L """ import math if not n >= 0: raise ValueError("n must be >= 0")... 31

32 Haskell Haddock 32

33 Haddock -- unlines is an inverse operation to lines. -- It joins lines, after appending a terminating -- newline to each. unlines :: [String] -> String unlines [] = [] unlines (l:ls) = l ++ \n : unlines ls Haddock HTML 33

34 ">" Data.Map -- /O(1)/. Is the map empty? > Data.Map.null (empty) == True -- > Data.Map.null (singleton 1 a ) == False null :: Map k a -> Bool null Tip = True null (Bin _) = False 34

35 35

36 Simon HENGEL ">>>" >>> length [] 0 >>> writefile "tmpfile" "Hello" >>> readfile "tmpfile" "Hello" >>> head [] *** Exception: Prelude.head: empty list Haddock

37 doctest Haddock Haddock API 0.6 GHC API GHCi doctest 0.6.x GHCi 0.7 GHCi 37

38 "prop>" prop> Data.Map.null empty == True prop> \xs -> sort xs == sort (sort (xs::[int])) prop> sort xs == sort (sort (xs::[int])) Haddock 38

39 haskell-src-exts... GHCi > sort xs == sort (sort (xs::[int])) <interactive>:1:6: Not in scope: xs <interactive>:1:24: Not in scope: xs "\xs -> " 39

40 doctest doctest 40

41 v2.3 QuickCheck > quickcheck $ length [] == OK, passed 100 tests. True 100 v2.4 > quickcheck $ length [] == OK, passed 1 tests. 41

42 / > valid $ deletemin $ deletemin $ fromlist [(i,()) i <- [0,2,5,1,6,4,8,9,7,11,10,3]] False 42

43 Trystan SPANGLER Hspec 43

44 Q) Hspec A) Ruby Rspec Haskell Rspec BDD 44

45 Q) BDD (Behavior Driven Development) A) TDD (Test Driven Development) 45

46 Haskell 46

47 Hspec describe "deletemin" $ do it "maintains the balance even if applied doubly" $ valid $ deletemin $ deletemin $ fromlist [(i::int,()) i <- [0,2,5,1,6,4,8,9,7,11,10,3]] it... it... it... 47

48 IO setup teardown withdb action = bracket (connectsqlite3 "my.db") disconnect action describe "database adaptor" $ do it "returns 23, when 23 is selected" $ withdb $ \connection -> run connection "select 23;" shouldreturn 23 48

49 Haskell Behavior Driven Development 49

50 Haskell BDD (1) (1) rev :: [a] -> [a] rev = undefined undefined undefined undefined placeholders notimplemented todo 50

51 Haskell BDD (2) (2) Haddock rev returns the elements of -- in reverse order. must be finite >>> rev [1,2,3] -- [3,2,1] prop> rev [] == rev [] -- prop> rev (xs++ys) == rev ys ++ rev (xs::[int]) -- prop> rev (rev xs) == (xs::[int]) rev :: [a] -> [a] rev = undefined 51

52 Haskell BDD (3) (3) Hspec describe "rev" $ do it "returns the first element in the last" $ property $ \xs -> not (null xs) ==> head (rev xs) == last (xs :: [Int]) it "returns the last element in the first" $ property $ \xs -> not (null xs) ==> last (rev xs) == head (xs :: [Int]) 52

53 (4) Haskell BDD (4) rev :: [a] -> [a] rev = foldl (flip (:)) [] doctest Hspec Cabal cabal test test-suite doctests type: exitcode-stdio-1.0 main-is: doctests.hs build-depends: base, doctest test-suite spec type: exitcode-stdio-1.0 main-is: Spec.hs build-depends: base, hspec 53

54 rev = foldl (flip (:)) [] ghc-mod rev :: [a] -> [a] rev = foldl (flip (:)) [] >>> rev [1,2,3] -- [3,2,1] rev :: [a] -> [a] rev = foldl (flip (:)) [] 54

55 QuickCheck doctest Hspec ( ) Cabal 55

56 Simon HENGEL (doctest Hspec ) Hspec github issue 56

test.gby

test.gby Beautiful Programming Language and Beautiful Testing 1 Haskeller Haskeller 2 Haskeller (Doctest QuickCheck ) github 3 Haskeller 4 Haskell Platform 2011.4.0.0 Glasgow Haskell Compiler + 23 19 8 5 10 5 Q)