correctly calculate goalie average

ChangeLog.md

@@ -5,6 +5,7 @@
 - Allow lower case player names
 - Don't show players without points in game report
 - Removed unnecessary goalie statistics from game report
+- Fixed goalie average calculation
 
 ## 0.7.0
 - Shortened views to fit within 25 lines

src/Mtlstats/Types.hs

@@ -1010,4 +1010,10 @@ addGoalieStats g1 g2 = GoalieStats
 
 -- | Determines a goalie's average goals allowed per game.
 gsAverage :: GoalieStats -> Rational
-gsAverage gs = fromIntegral (gs^.gsGoalsAllowed) / fromIntegral (gs^.gsGames)
+gsAverage gs = let
+  allowed = fromIntegral $ gs^.gsGoalsAllowed
+  mins    = fromIntegral $ gs^.gsMinsPlayed
+  gLen    = fromIntegral gameLength
+  in if mins == 0
+    then 0
+    else allowed / mins * gLen

test/TypesSpec.hs

@@ -813,15 +813,20 @@ addGoalieStatsSpec = describe "addGoalieStats" $ let
     actual `shouldBe` expected
 
 gsAverageSpec :: Spec
-gsAverageSpec = describe "gsAverage" $ let
-  gs = newGoalieStats
-    & gsGames        .~ 2
-    & gsGoalsAllowed .~ 3
+gsAverageSpec = describe "gsAverage" $ mapM_
+  (\(label, stats, expected) -> context label $
+    it ("should be " ++ show expected) $
+      gsAverage stats `shouldBe` expected)
 
-  expected = 3 % 2
+  --  label,          stats,           expected
+  [ ( "with minutes", gs,              3 % 2    )
+  , ( "no minutes",   newGoalieStats , 0        )
+  ]
 
-  in it ("should be " ++ show expected) $
-    gsAverage gs `shouldBe` expected
+  where
+    gs = newGoalieStats
+      & gsMinsPlayed   .~ 2 * gameLength
+      & gsGoalsAllowed .~ 3
 
 joe :: Player
 joe = newPlayer 2 "Joe" "center"