Add missing uses to SubstanceAmount

Defined missing centimoles & decimoles in SubstanceAmount
module. Include in commit tests for fuzzing these and equal
pair comparisons.

See also ianmackenzie#6

src/SubstanceAmount.elm

@@ -1,8 +1,9 @@
 module SubstanceAmount exposing
     ( SubstanceAmount, Moles
     , moles, inMoles, picomoles, inPicomoles, nanomoles, inNanomoles
-    , micromoles, inMicromoles, millimoles, inMillimoles, kilomoles, inKilomoles
-    , megamoles, inMegamoles, gigamoles, inGigamoles
+    , micromoles, inMicromoles, millimoles, inMillimoles
+    , centimoles, inCentimoles, decimoles, inDecimoles
+    , kilomoles, inKilomoles, megamoles, inMegamoles, gigamoles, inGigamoles
     )
 
 {-| A `SubstanceAmount` value represents a substance amount in [moles][1].
@@ -15,8 +16,9 @@ module SubstanceAmount exposing
 ## Conversions
 
 @docs moles, inMoles, picomoles, inPicomoles, nanomoles, inNanomoles
-@docs micromoles, inMicromoles, millimoles, inMillimoles, kilomoles, inKilomoles
-@docs megamoles, inMegamoles, gigamoles, inGigamoles
+@docs micromoles, inMicromoles, millimoles, inMillimoles
+@docs centimoles, inCentimoles, decimoles, inDecimoles
+@docs kilomoles, inKilomoles, megamoles, inMegamoles, gigamoles, inGigamoles
 
 -}
 
@@ -103,6 +105,34 @@ inMillimoles substanceAmount =
     inMoles substanceAmount / 1.0e-3
 
 
+{-| Construct a substance amount from a number of centimoles.
+-}
+centimoles : Float -> SubstanceAmount
+centimoles numCentimoles =
+    moles (numCentimoles * 1.0e-2)
+
+
+{-| Convert a substance amount to a number of centimoles.
+-}
+inCentimoles : SubstanceAmount -> Float
+inCentimoles substanceAmount =
+    inMoles substanceAmount / 1.0e-2
+
+
+{-| Construct a substance amount from a number of decimoles.
+-}
+decimoles : Float -> SubstanceAmount
+decimoles numDecimoles =
+    moles (numDecimoles * 1.0e-1)
+
+
+{-| Convert a substance amount to a number of decimoles.
+-}
+inDecimoles : SubstanceAmount -> Float
+inDecimoles substanceAmount =
+    inMoles substanceAmount / 1.0e-1
+
+
 {-| Construct a substance amount from a number of kilomoles.
 -}
 kilomoles : Float -> SubstanceAmount

tests/Tests.elm

@@ -242,9 +242,18 @@ substanceAmount =
         , ( nanomoles 1000000
           , millimoles 1
           )
+        , ( centimoles 600
+          , decimoles 60
+          )
         , ( moles 1
           , millimoles 1000
           )
+        , ( moles 4
+          , centimoles 400
+          )
+        , ( moles 2
+          , decimoles 20
+          )
         , ( moles 2000
           , kilomoles 2
           )
@@ -575,6 +584,8 @@ conversionsToQuantityAndBack =
             , fuzzFloatToQuantityAndBack "nanomoles" SubstanceAmount.nanomoles SubstanceAmount.inNanomoles
             , fuzzFloatToQuantityAndBack "micromoles" SubstanceAmount.micromoles SubstanceAmount.inMicromoles
             , fuzzFloatToQuantityAndBack "millimoles" SubstanceAmount.millimoles SubstanceAmount.inMillimoles
+            , fuzzFloatToQuantityAndBack "centimoles" SubstanceAmount.centimoles SubstanceAmount.inCentimoles
+            , fuzzFloatToQuantityAndBack "decimoles" SubstanceAmount.decimoles SubstanceAmount.inDecimoles
             , fuzzFloatToQuantityAndBack "kilomoles" SubstanceAmount.kilomoles SubstanceAmount.inKilomoles
             , fuzzFloatToQuantityAndBack "megamoles" SubstanceAmount.megamoles SubstanceAmount.inMegamoles
             , fuzzFloatToQuantityAndBack "gigamoles" SubstanceAmount.gigamoles SubstanceAmount.inGigamoles