use partial functions in tests

I claim that it's ok because if the match is non-exhaustive then the
test will fail anyway

tests/UnitTest.hs

@@ -69,32 +69,28 @@ testMalformed = TestCase $
 test2 = TestCase $
         either
         (assertFailure . displayException)
-        (\ trk -> case trk of
+        (\ (p:_) ->
-          p:_ ->
            assertEqual "matches lat/lon"
            (Track.Pos 51.0 (-0.1))
-             (Track.pos p)
+           (Track.pos p))
-          [] -> assertFailure "no points")
         (Track.parse onepoint)
 
 test3 = TestCase $
-        case Track.parse onepoint
+        either
-        of
+        (assertFailure . displayException)
-          Left err -> assertFailure (displayException err)
+        (\ (p:_) ->
-          Right (p:ps) ->
+           assertEqual "handles missing attributes"
-            assertEqual "matches attributes"
+             (Nothing, Nothing) (Track.elevation p, Track.cadence p))
-             (Nothing, Nothing) (Track.elevation p, Track.cadence p)
+        (Track.parse onepoint)
-          Right [] -> assertFailure "no points"
 
 test4 = TestCase $
-        case Track.parse onepointWithAttrs
+        either
-        of
+        (assertFailure . displayException)
-          Left err -> assertFailure (displayException err)
+        (\ (p:_) ->
-          Right (p:ps) ->
+           assertEqual "handles attributes"
-            assertEqual "matches attributes"
              (Just 25.2, Just 128, Just 55, Data.Time.UTCTime (toEnum 60606) 27299.779)
-             (Track.elevation p, Track.cadence p, Track.power p, Track.time p)
+             (Track.elevation p, Track.cadence p, Track.power p, Track.time p))
-          Right [] -> assertFailure "no points"
+        (Track.parse onepointWithAttrs)
 
 tests :: Test
 tests = TestList [