test calls actual code we wrote

lib/Track.hs

@@ -0,0 +1,17 @@
+module Track where
+import Data.Time
+import qualified Data.List
+data Pos = Pos Float Float
+
+
+data Point = Point Pos UTCTime
+
+type Track = [Point]
+
+parse :: String -> Track
+parse str = [
+  -- Point (Pos 516 0) (UTCTime (toEnum  60631) 43200)
+  ]
+
+length :: Track -> Int
+length trk = Data.List.length trk

souplesse.cabal

@@ -79,6 +79,17 @@ executable souplesse
 -- mostly copied from
 -- https://functional.works-hub.com/learn/basic-unit-testing-in-haskell-using-hunit-and-cabal-29e47
 
+library souplesse-lib
+    exposed-modules:
+        Track
+    hs-source-dirs:
+        lib
+    build-depends:
+        base >=4.7 && <5
+      , HaXml
+      , time
+    default-language: GHC2021
+
 test-suite tests
     type: exitcode-stdio-1.0
     main-is: UnitTest.hs
@@ -86,5 +97,6 @@ test-suite tests
         tests
     build-depends:
         base >=4.7 && <5
+      , souplesse-lib
       , HUnit
     default-language: GHC2021

tests/UnitTest.hs

@@ -1,10 +1,17 @@
 module Main where
--- import BasicSum
+
+import qualified Track (Track, parse, length )
 import Test.HUnit
 import qualified System.Exit as Exit
 
+
 test1 :: Test
-test1 = TestCase (assertEqual "should return 3" 3 (1 + 2))
+test1 = TestCase $
+        let
+          trk = Track.parse "<gpx></gpx>"
+        in
+          assertEqual "empty track has no elements"
+          0 (Track.length trk)
 
 tests :: Test
 tests = TestList [TestLabel "test1" test1]