TESTS: add more function documentation

Test/Vector.hs

@@ -19,60 +19,79 @@ instance Arbitrary P2 where
   arbitrary = curry p2 <$> arbitrary <*> arbitrary
 
 
+-- the point describing the lower left corner of the square
+-- must be part of the square
 inRangeProp1 :: Square -> Bool
 inRangeProp1 sq@((x1, y1), _) =
   inRange sq (p2 (x1, y1))
 
 
+-- the point describing the upper right corner of the square
+-- must be part of the square
 inRangeProp2 :: Square -> Bool
 inRangeProp2 sq@(_, (x2, y2)) =
   inRange sq (p2 (x2, y2))
 
 
+-- the point describing the upper left corner of the square
+-- must be part of the square
 inRangeProp3 :: Square -> Bool
 inRangeProp3 sq@((x1, _), (_, y2)) =
   inRange sq (p2 (x1, y2))
 
 
+-- the point describing the lower right corner of the square
+-- must be part of the square
 inRangeProp4 :: Square -> Bool
 inRangeProp4 sq@((_, y1), (x2, _)) =
   inRange sq (p2 (x2, y1))
 
 
+-- generating random points within the square
 inRangeProp5 :: Square -> Positive Double -> Positive Double -> Bool
 inRangeProp5 sq@((x1, y1), (x2, y2)) (Positive a) (Positive b) =
   inRange sq (p2 (x1 + ((x2 - x1) / (a + 1)), y1 + ((y2 - y1) / (b + 1))))
 
 
+-- apply id function on the point
 onPTProp1 :: PT -> Bool
 onPTProp1 pt = onPT id pt == pt
 
 
+-- add a random value to the point coordinates
 onPTProp2 :: PT -> Positive R2 -> Bool
 onPTProp2 pt (Positive (R2 rx ry))
   = onPT (\(x, y) -> (x + rx, y + ry)) pt /= pt
 
 
+-- angle between two vectors both on the x-axis must be 0
 getAngleProp1 :: Positive Vec -> Positive Vec -> Bool
 getAngleProp1 (Positive (R2 x1 _)) (Positive (R2 x2 _))
   = getAngle (R2 x1 0) (R2 x2 0) == 0
 
 
+-- angle between two vectors both on the y-axis must be 0
 getAngleProp2 :: Positive Vec -> Positive Vec -> Bool
 getAngleProp2 (Positive (R2 _ y1)) (Positive (R2 _ y2))
   = getAngle (R2 0 y1) (R2 0 y2) == 0
 
 
+-- angle between two vectors both on the x-axis but with opposite direction
+-- must be pi
 getAngleProp3 :: Positive Vec -> Positive Vec -> Bool
 getAngleProp3 (Positive (R2 x1 _)) (Positive (R2 x2 _))
   = getAngle (R2 (negate x1) 0) (R2 x2 0) == pi
 
 
+-- angle between two vectors both on the y-axis but with opposite direction
+-- must be pi
 getAngleProp4 :: Positive Vec -> Positive Vec -> Bool
 getAngleProp4 (Positive (R2 _ y1)) (Positive (R2 _ y2))
   = getAngle (R2 0 (negate y1)) (R2 0 y2) == pi
 
 
+-- angle between vector in x-axis direction and y-axis direction must be
+-- p/2
 getAngleProp5 :: Positive Vec -> Positive Vec -> Bool
 getAngleProp5 (Positive (R2 x1 _)) (Positive (R2 _ y2))
   = getAngle (R2 x1 0) (R2 0 y2) == pi / 2