implemented getNumRungs

test/AbacusSpec.hs

@@ -31,6 +31,7 @@ spec :: Spec
 spec = describe "Abacus" $ do
   newAbacusSpec
   getNumBeadsSpec
+  getNumRungsSpec
 
 newAbacusSpec :: Spec
 newAbacusSpec = describe "newAbacusSpec" $ mapM_
@@ -58,4 +59,18 @@ getNumBeadsSpec = describe "getNumBeads" $ mapM_
     tenBeads = build 10
     build n = fromJust $ newAbacus n 10
 
+getNumRungsSpec :: Spec
+getNumRungsSpec = describe "getNumRungs" $ mapM_
+  ( \(desc, input, expected) -> context desc $ let
+    actual = getNumRungs input
+    in it ("should be " ++ show expected) $
+      actual `shouldBe` expected
+  )
+  [ ( "one rung",  oneRung,  1  )
+  , ( "ten rungs", tenRungs, 10 )
+  ] where
+    oneRung = build 1
+    tenRungs = build 10
+    build n = fromJust $ newAbacus 10 n
+
 --jl