implemented padNum

src/Mtlstats/Format.hs

@@ -0,0 +1,38 @@
+{- |
+
+mtlstats
+Copyright (C) 2019 Rhéal Lamothe
+<rheal.lamothe@gmail.com>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or (at
+your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+-}
+
+module Mtlstats.Format (padNum) where
+
+-- | Pad an 'Int' with leading zeroes to fit a certain character width
+padNum
+  :: Int
+  -- ^ The width in characters
+  -> Int
+  -- ^ The value to format
+  -> String
+padNum size n
+  | n < 0 = '-' : padNum (pred size) (-n)
+  | otherwise = let
+    str  = show n
+    sLen = length str
+    pLen = size - sLen
+    pad  = replicate pLen '0'
+    in pad ++ str

test/FormatSpec.hs

@@ -0,0 +1,53 @@
+{-
+
+mtlstats
+Copyright (C) 2019 Rhéal Lamothe
+<rheal.lamothe@gmail.com>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or (at
+your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+-}
+
+module FormatSpec (spec) where
+
+import Test.Hspec (Spec, context, describe, it, shouldBe)
+
+import Mtlstats.Format
+
+spec :: Spec
+spec = describe "Mtlstats.Format"
+  padNumSpec
+
+padNumSpec :: Spec
+padNumSpec = describe "padNum" $ do
+
+  context "zero, four digits" $
+    it "should be 0000" $
+      padNum 4 0 `shouldBe` "0000"
+
+  context "123, four digits" $
+    it "should be 0123" $
+      padNum 4 123 `shouldBe` "0123"
+
+  context "12345, four digits" $
+    it "should be 12345" $
+      padNum 4 12345 `shouldBe` "12345"
+
+  context "-12, four digits" $
+    it "should be -012" $
+      padNum 4 (-12) `shouldBe` "-012"
+
+  context "-1234, four digits" $
+    it "should be -1234" $
+      padNum 4 (-1234) `shouldBe` "-1234"

test/Spec.hs

@@ -22,9 +22,11 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 import Test.Hspec (hspec)
 
 import qualified ActionsSpec as Actions
+import qualified FormatSpec as Format
 import qualified TypesSpec as Types
 
 main :: IO ()
 main = hspec $ do
   Types.spec
   Actions.spec
+  Format.spec