Misc changes from Monday meeting.

src/contracts/Cash.kt

@@ -63,7 +63,6 @@ object Cash : Contract {
         val cashInputs = inStates.filterIsInstance<Cash.State>()
 
         requireThat {
-            "there is at least one cash input" by cashInputs.isNotEmpty()
             "there are no zero sized inputs" by cashInputs.none { it.amount.pennies == 0 }
             "all inputs use the same currency" by (cashInputs.groupBy { it.amount.currency }.size == 1)
         }

src/contracts/ComedyPaper.kt

@@ -58,6 +58,8 @@ object ComedyPaper : Contract {
 
             is Commands.Redeem -> requireThat {
                 val received = outStates.sumCash()
+                // Do we need to check the signature of the issuer here too?
+                "the transaction is signed by the owner of the CP" by (command.signer == input.owner)
                 "the paper must have matured" by (input.maturityDate < time)
                 "the received amount equals the face value" by (received == input.faceValue)
                 "the paper must be destroyed" by outStates.filterIsInstance<ComedyPaper.State>().none()

tests/contracts/CashTests.kt

@@ -24,8 +24,6 @@ class CashTests {
     @Test
     fun trivial() {
         transaction {
-            contract `fails requirement` "there is at least one cash input"
-
             input { inState }
             contract `fails requirement` "the amounts balance"