Merge pull request #818 from mindofmatthew/signal-tests

Test and bugfix basic patterns (sine, etc)

src/Sound/Tidal/Core.hs

@@ -62,7 +62,7 @@ cosine = 0.25 `rotR` sine
 -- following a cosine with frequency of one cycle, and amplitude from
 -- -1 to 1. Equivalent to `0.25 ~> sine2`.
 cosine2 :: Fractional a => Pattern a
-cosine2 = 0.25 `rotR` sine
+cosine2 = 0.25 `rotR` sine2
 
 -- | @saw@ - unipolar ascending sawtooth wave. A pattern of continuous values
 -- following a sawtooth with frequency of one cycle, and amplitude from
@@ -82,7 +82,7 @@ isaw = (1-) <$> saw
 
 -- | @isaw2@ like @saw2@, but a descending (inverse) sawtooth.
 isaw2 :: (Fractional a, Real a) => Pattern a
-isaw2 = (1-) <$> saw
+isaw2 = (*(-1)) <$> saw2
 
 -- | @tri@ - unipolar triangle wave. A pattern of continuous values
 -- following a triangle wave with frequency of one cycle, and amplitude from
@@ -94,7 +94,7 @@ tri = fastAppend saw isaw
 -- following a triangle wave with frequency of one cycle, and amplitude from
 -- -1 to 1.
 tri2 :: (Fractional a, Real a) => Pattern a
-tri2 = fastAppend saw isaw
+tri2 = fastAppend saw2 isaw2
 
 -- | @square@ - unipolar square wave. A pattern of continuous values
 -- following a square wave with frequency of one cycle, and amplitude from

test/Sound/Tidal/CoreTest.hs

@@ -4,6 +4,7 @@ module Sound.Tidal.CoreTest where
 
 import Data.List (sort)
 import Data.Ratio
+import qualified Data.Map as Map
 import Sound.Tidal.Context
 import Test.Microspec
 import TestUtils
@@ -12,6 +13,29 @@ import Prelude hiding ((*>), (<*))
 run :: Microspec ()
 run =
   describe "Sound.Tidal.Core" $ do
+    describe "Elemental patterns" $ do
+      let sampleOf :: Pattern Double -> Rational -> Double
+          sampleOf pat t = (value . head) $ query pat (State (Arc t t) Map.empty)
+      describe "are in range [0, 1]" $ do
+        let inNormalRange pat t = (y >= 0) && (y <= 1)
+              where y = sampleOf pat t
+        it "sine" $ inNormalRange sine
+        it "cosine" $ inNormalRange cosine
+        it "saw" $ inNormalRange saw
+        it "isaw" $ inNormalRange isaw
+        it "tri" $ inNormalRange tri
+        it "square" $ inNormalRange square
+      describe "have correctly-scaled bipolar variants" $ do
+        let areCorrectlyScaled pat pat2 t = (y * 2 - 1) ~== y2
+              where y = sampleOf pat t
+                    y2 = sampleOf pat2 t
+        it "sine" $ areCorrectlyScaled sine sine2
+        it "cosine" $ areCorrectlyScaled cosine cosine2
+        it "saw" $ areCorrectlyScaled saw saw2
+        it "isaw" $ areCorrectlyScaled isaw isaw2
+        it "tri" $ areCorrectlyScaled tri tri2
+        it "square" $ areCorrectlyScaled square square2
+
     describe "append" $
       it "can switch between the cycles from two pures" $ do
         queryArc (append (pure "a") (pure "b")) (Arc 0 5)
@@ -23,6 +47,7 @@ run =
               (((3, 4), (3, 4)), "b"),
               (((4, 5), (4, 5)), "a")
             ]
+
     describe "cat" $ do
       it "can switch between the cycles from three pures" $ do
         queryArc (cat [pure "a", pure "b", pure "c"]) (Arc 0 5)
@@ -42,6 +67,7 @@ run =
               (Arc 0 10)
               (rev $ cat [a, b, c])
               (cat [rev a, rev b, rev c])
+
     describe "fastCat" $ do
       it "can switch between the cycles from three pures inside one cycle" $ do
         it "1" $

test/TestUtils.hs

@@ -15,6 +15,9 @@ import qualified Data.Map.Strict as Map
 class TolerantEq a where
    (~==) :: a -> a -> Bool
 
+instance TolerantEq Double where
+  a ~== b = abs (a - b) < 0.000001
+
 instance TolerantEq Value where
          (VS a) ~== (VS b) = a == b
          (VI a) ~== (VI b) = a == b