diff --git a/core/src/main/kotlin/com/r3corda/core/contracts/ContractsDSL.kt b/core/src/main/kotlin/com/r3corda/core/contracts/ContractsDSL.kt
index 4e36dc0d69..3e7e06def1 100644
--- a/core/src/main/kotlin/com/r3corda/core/contracts/ContractsDSL.kt
+++ b/core/src/main/kotlin/com/r3corda/core/contracts/ContractsDSL.kt
@@ -93,11 +93,21 @@ fun List<AuthenticatedObject<CommandData>>.getTimestampByName(vararg names: Stri
 @Throws(IllegalArgumentException::class)
 // TODO: Can we have a common Move command for all contracts and avoid the reified type parameter here?
 inline fun <reified T : CommandData> verifyMoveCommand(inputs: List<OwnableState>, tx: TransactionForContract) {
+    return verifyMoveCommand<T>(inputs, tx.commands)
+}
+
+/**
+ * Simple functionality for verifying a move command. Verifies that each input has a signature from its owning key.
+ *
+ * @param T the type of the move command
+ */
+@Throws(IllegalArgumentException::class)
+inline fun <reified T : CommandData> verifyMoveCommand(inputs: List<OwnableState>, commands: List<AuthenticatedObject<CommandData>>) {
     // Now check the digital signatures on the move command. Every input has an owning public key, and we must
     // see a signature from each of those keys. The actual signatures have been verified against the transaction
     // data by the platform before execution.
     val owningPubKeys = inputs.map { it.owner }.toSet()
-    val keysThatSigned = tx.commands.requireSingleCommand<T>().signers.toSet()
+    val keysThatSigned = commands.requireSingleCommand<T>().signers.toSet()
     requireThat {
         "the owning keys are the same as the signing keys" by keysThatSigned.containsAll(owningPubKeys)
     }
diff --git a/core/src/main/kotlin/com/r3corda/core/contracts/TransactionVerification.kt b/core/src/main/kotlin/com/r3corda/core/contracts/TransactionVerification.kt
index 2b3c5551dd..bd83d1a629 100644
--- a/core/src/main/kotlin/com/r3corda/core/contracts/TransactionVerification.kt
+++ b/core/src/main/kotlin/com/r3corda/core/contracts/TransactionVerification.kt
@@ -93,6 +93,9 @@ data class TransactionForContract(val inputs: List<ContractState>,
     @Deprecated("This property was renamed to outputs", ReplaceWith("outputs"))
     val outStates: List<ContractState> get() = outputs
 
+    inline fun <reified T: CommandData, K> groupCommands(keySelector: (AuthenticatedObject<T>) -> K): Map<K, List<AuthenticatedObject<T>>>
+        = commands.select<T>().groupBy(keySelector)
+
     /**
      * Given a type and a function that returns a grouping key, associates inputs and outputs together so that they
      * can be processed as one. The grouping key is any arbitrary object that can act as a map key (so must implement
diff --git a/core/src/main/kotlin/com/r3corda/core/testing/TestUtils.kt b/core/src/main/kotlin/com/r3corda/core/testing/TestUtils.kt
index 925a8f5983..1cae30a37c 100644
--- a/core/src/main/kotlin/com/r3corda/core/testing/TestUtils.kt
+++ b/core/src/main/kotlin/com/r3corda/core/testing/TestUtils.kt
@@ -295,7 +295,7 @@ class TransactionGroupDSL<T : ContractState>(private val stateType: Class<T>) {
     fun labelForState(output: TransactionState<*>): String? = outputsToLabels[output]
 
     inner class Roots {
-        fun transaction(vararg outputStates: LabeledOutput) {
+        fun transaction(vararg outputStates: LabeledOutput): Roots {
             val outs = outputStates.map { it.state }
             val wtx = WireTransaction(emptyList(), emptyList(), outs, emptyList(), emptyList(), TransactionType.General())
             for ((index, state) in outputStates.withIndex()) {
@@ -305,6 +305,7 @@ class TransactionGroupDSL<T : ContractState>(private val stateType: Class<T>) {
                 labelToOutputs[label] = state.state as TransactionState<T>
             }
             rootTxns.add(wtx)
+            return this
         }
 
         /**
@@ -370,8 +371,8 @@ class TransactionGroupDSL<T : ContractState>(private val stateType: Class<T>) {
             verify()
         }
         assertEquals(index, e.index)
-        if (!e.cause!!.message!!.contains(message))
-            throw AssertionError("Exception should have said '$message' but was actually: ${e.cause.message}", e.cause)
+        if (!(e.cause?.message ?: "") .contains(message))
+            throw AssertionError("Exception should have said '$message' but was actually: ${e.cause?.message}", e.cause)
         return e
     }