Matchers (#3716)

* Move common matches to testing, add some missing ones

* Clarify test logic

* Move common matches to testing, add some missing ones

* Clarify test logic

* Rename 'randomise'

* endregion

* Fix broken unit test

confidential-identities/src/test/kotlin/net/corda/confidential/SwapIdentitiesFlowTests.kt

@@ -1,54 +1,59 @@
 package net.corda.confidential
 
+import com.natpryce.hamkrest.MatchResult
+import com.natpryce.hamkrest.Matcher
+import com.natpryce.hamkrest.equalTo
 import net.corda.core.identity.*
-import net.corda.core.utilities.getOrThrow
 import net.corda.testing.core.*
+import net.corda.testing.internal.matchers.allOf
+import net.corda.testing.internal.matchers.flow.willReturn
 import net.corda.testing.node.internal.InternalMockNetwork
 import net.corda.testing.node.internal.startFlow
-import org.junit.Before
 import org.junit.Test
 import kotlin.test.*
+import com.natpryce.hamkrest.assertion.assert
+import net.corda.core.crypto.DigitalSignature
+import net.corda.testing.internal.matchers.hasOnlyEntries
+import net.corda.testing.node.internal.TestStartedNode
+import org.junit.AfterClass
+import java.security.PublicKey
 
 class SwapIdentitiesFlowTests {
-    private lateinit var mockNet: InternalMockNetwork
+    companion object {
+        private val mockNet = InternalMockNetwork(networkSendManuallyPumped = false, threadPerNode = true)
 
-    @Before
+        @AfterClass
-    fun setup() {
+        @JvmStatic
-        // We run this in parallel threads to help catch any race conditions that may exist.
+        fun tearDown() = mockNet.stopNodes()
-        mockNet = InternalMockNetwork(networkSendManuallyPumped = false, threadPerNode = true)
     }
 
+    private val aliceNode = mockNet.createPartyNode(makeUnique(ALICE_NAME))
+    private val bobNode = mockNet.createPartyNode(makeUnique(BOB_NAME))
+    private val charlieNode = mockNet.createPartyNode(makeUnique(CHARLIE_NAME))
+    private val alice = aliceNode.info.singleIdentity()
+    private val bob = bobNode.info.singleIdentity()
+
     @Test
     fun `issue key`() {
-        // Set up values we'll need
+        assert.that(
-        val aliceNode = mockNet.createPartyNode(ALICE_NAME)
+            aliceNode.services.startFlow(SwapIdentitiesFlow(bob)),
-        val bobNode = mockNet.createPartyNode(BOB_NAME)
+            willReturn(
-        val alice = aliceNode.info.singleIdentity()
+                hasOnlyEntries(
-        val bob = bobNode.services.myInfo.singleIdentity()
+                    alice to allOf(
-
+                        !equalTo<AbstractParty>(alice),
-        // Run the flows
+                        aliceNode.resolvesToWellKnownParty(alice),
-        val requesterFlow = aliceNode.services.startFlow(SwapIdentitiesFlow(bob)).resultFuture
+                        aliceNode.holdsOwningKey(),
-
+                        !bobNode.holdsOwningKey()
-        // Get the results
+                    ),
-        val actual: Map<Party, AnonymousParty> = requesterFlow.getOrThrow().toMap()
+                    bob to allOf(
-        assertEquals(2, actual.size)
+                        !equalTo<AbstractParty>(bob),
-        // Verify that the generated anonymous identities do not match the well known identities
+                        bobNode.resolvesToWellKnownParty(bob),
-        val aliceAnonymousIdentity = actual[alice] ?: throw IllegalStateException()
+                        bobNode.holdsOwningKey(),
-        val bobAnonymousIdentity = actual[bob] ?: throw IllegalStateException()
+                        !aliceNode.holdsOwningKey()
-        assertNotEquals<AbstractParty>(alice, aliceAnonymousIdentity)
+                    )
-        assertNotEquals<AbstractParty>(bob, bobAnonymousIdentity)
+                )
-
+            )
-        // Verify that the anonymous identities look sane
+        )
-        assertEquals(alice.name, aliceNode.database.transaction { aliceNode.services.identityService.wellKnownPartyFromAnonymous(aliceAnonymousIdentity)!!.name })
-        assertEquals(bob.name, bobNode.database.transaction { bobNode.services.identityService.wellKnownPartyFromAnonymous(bobAnonymousIdentity)!!.name })
-
-        // Verify that the nodes have the right anonymous identities
-        assertTrue { aliceAnonymousIdentity.owningKey in aliceNode.services.keyManagementService.keys }
-        assertTrue { bobAnonymousIdentity.owningKey in bobNode.services.keyManagementService.keys }
-        assertFalse { aliceAnonymousIdentity.owningKey in bobNode.services.keyManagementService.keys }
-        assertFalse { bobAnonymousIdentity.owningKey in aliceNode.services.keyManagementService.keys }
-
-        mockNet.stopNodes()
     }
 
     /**
@@ -56,58 +61,101 @@ class SwapIdentitiesFlowTests {
      */
     @Test
     fun `verifies identity name`() {
-        // Set up values we'll need
+        val notBob = charlieNode.issueFreshKeyAndCert()
-        val aliceNode = mockNet.createPartyNode(ALICE_NAME)
+        val signature = charlieNode.signSwapIdentitiesFlowData(notBob, notBob.owningKey)
-        val bobNode = mockNet.createPartyNode(BOB_NAME)
+        assertFailsWith<SwapIdentitiesException>(
-        val charlieNode = mockNet.createPartyNode(CHARLIE_NAME)
+            "Certificate subject must match counterparty's well known identity.") {
-        val bob: Party = bobNode.services.myInfo.singleIdentity()
+            aliceNode.validateSwapIdentitiesFlow(bob, notBob, signature)
-        val notBob = charlieNode.database.transaction {
-            charlieNode.services.keyManagementService.freshKeyAndCert(charlieNode.services.myInfo.singleIdentityAndCert(), false)
         }
-        val sigData = SwapIdentitiesFlow.buildDataToSign(notBob)
-        val signature = charlieNode.services.keyManagementService.sign(sigData, notBob.owningKey)
-        assertFailsWith<SwapIdentitiesException>("Certificate subject must match counterparty's well known identity.") {
-            SwapIdentitiesFlow.validateAndRegisterIdentity(aliceNode.services.identityService, bob, notBob, signature.withoutKey())
-        }
-
-        mockNet.stopNodes()
     }
 
     /**
      * Check that flow is actually validating its the signature presented by the counterparty.
      */
     @Test
-    fun `verifies signature`() {
+    fun `verification rejects signature if name is right but key is wrong`() {
-        // Set up values we'll need
+        val evilBobNode = mockNet.createPartyNode(bobNode.info.singleIdentity().name)
-        val aliceNode = mockNet.createPartyNode(ALICE_NAME)
-        val bobNode = mockNet.createPartyNode(BOB_NAME)
-        val alice: PartyAndCertificate = aliceNode.info.singleIdentityAndCert()
-        val bob: PartyAndCertificate = bobNode.info.singleIdentityAndCert()
-        // Check that the right name but wrong key is rejected
-        val evilBobNode = mockNet.createPartyNode(BOB_NAME)
         val evilBob = evilBobNode.info.singleIdentityAndCert()
-        evilBobNode.database.transaction {
+        val anonymousEvilBob = evilBobNode.issueFreshKeyAndCert()
-            val anonymousEvilBob = evilBobNode.services.keyManagementService.freshKeyAndCert(evilBob, false)
+        val signature = evilBobNode.signSwapIdentitiesFlowData(evilBob, anonymousEvilBob.owningKey)
-            val sigData = SwapIdentitiesFlow.buildDataToSign(evilBob)
-            val signature = evilBobNode.services.keyManagementService.sign(sigData, anonymousEvilBob.owningKey)
-            assertFailsWith<SwapIdentitiesException>("Signature does not match the given identity and nonce") {
-                SwapIdentitiesFlow.validateAndRegisterIdentity(aliceNode.services.identityService, bob.party, anonymousEvilBob, signature.withoutKey())
-            }
-        }
-        // Check that the right signing key, but wrong identity is rejected
-        val anonymousAlice: PartyAndCertificate = aliceNode.database.transaction {
-            aliceNode.services.keyManagementService.freshKeyAndCert(alice, false)
-        }
-        bobNode.database.transaction {
-            bobNode.services.keyManagementService.freshKeyAndCert(bob, false)
-        }.let { anonymousBob ->
-            val sigData = SwapIdentitiesFlow.buildDataToSign(anonymousAlice)
-            val signature = bobNode.services.keyManagementService.sign(sigData, anonymousBob.owningKey)
-            assertFailsWith<SwapIdentitiesException>("Signature does not match the given identity and nonce.") {
-                SwapIdentitiesFlow.validateAndRegisterIdentity(aliceNode.services.identityService, bob.party, anonymousBob, signature.withoutKey())
-            }
-        }
 
-        mockNet.stopNodes()
+        assertFailsWith<SwapIdentitiesException>(
+                "Signature does not match the given identity and nonce") {
+            aliceNode.validateSwapIdentitiesFlow(bob, anonymousEvilBob, signature)
+        }
     }
+
+    @Test
+    fun `verification rejects signature if key is right but name is wrong`() {
+        val anonymousAlice = aliceNode.issueFreshKeyAndCert()
+        val anonymousBob = bobNode.issueFreshKeyAndCert()
+        val signature = bobNode.signSwapIdentitiesFlowData(anonymousAlice, anonymousBob.owningKey)
+
+        assertFailsWith<SwapIdentitiesException>(
+                "Signature does not match the given identity and nonce.") {
+                aliceNode.validateSwapIdentitiesFlow(bob, anonymousBob, signature)
+        }
+    }
+
+    //region Operations
+    private fun TestStartedNode.issueFreshKeyAndCert() = database.transaction {
+        services.keyManagementService.freshKeyAndCert(services.myInfo.singleIdentityAndCert(), false)
+    }
+
+    private fun TestStartedNode.signSwapIdentitiesFlowData(party: PartyAndCertificate, owningKey: PublicKey) =
+            services.keyManagementService.sign(
+                    SwapIdentitiesFlow.buildDataToSign(party),
+                    owningKey)
+
+    private fun TestStartedNode.validateSwapIdentitiesFlow(
+            party: Party,
+            counterparty: PartyAndCertificate,
+            signature: DigitalSignature.WithKey) =
+            SwapIdentitiesFlow.validateAndRegisterIdentity(
+                    services.identityService,
+                    party,
+                    counterparty,
+                    signature.withoutKey()
+            )
+    //endregion
+
+    //region Matchers
+    private fun TestStartedNode.resolvesToWellKnownParty(party: Party) = object : Matcher<AnonymousParty> {
+        override val description = """
+            is resolved by "${this@resolvesToWellKnownParty.info.singleIdentity().name}" to well-known party "${party.name}"
+        """.trimIndent()
+
+        override fun invoke(actual: AnonymousParty): MatchResult {
+            val resolvedName = services.identityService.wellKnownPartyFromAnonymous(actual)!!.name
+            return if (resolvedName == party.name) {
+                MatchResult.Match
+            } else {
+                MatchResult.Mismatch("was resolved to $resolvedName")
+            }
+        }
+    }
+
+    private data class HoldsOwningKeyMatcher(val node: TestStartedNode, val negated: Boolean = false) : Matcher<AnonymousParty> {
+        private fun sayNotIf(negation: Boolean) = if (negation) { "not " } else { "" }
+
+        override val description =
+                "has an owning key which is ${sayNotIf(negated)}held by ${node.info.singleIdentity().name}"
+
+        override fun invoke(actual: AnonymousParty) =
+                if (negated != actual.owningKey in node.services.keyManagementService.keys) {
+                    MatchResult.Match
+                } else {
+                    MatchResult.Mismatch("""
+                    had an owning key which was ${sayNotIf(!negated)}held by ${node.info.singleIdentity().name}
+                    """.trimIndent())
+                }
+
+        override fun not(): Matcher<AnonymousParty> {
+            return copy(negated=!negated)
+        }
+    }
+
+    private fun TestStartedNode.holdsOwningKey() = HoldsOwningKeyMatcher(this)
+    //endregion
+
 }

core/src/test/kotlin/net/corda/core/flows/AttachmentTests.kt

@@ -5,8 +5,8 @@ import com.natpryce.hamkrest.*
 import com.natpryce.hamkrest.assertion.assert
 import net.corda.core.contracts.Attachment
 import net.corda.core.crypto.SecureHash
-import net.corda.core.flows.matchers.flow.willReturn
+import net.corda.testing.internal.matchers.flow.willReturn
-import net.corda.core.flows.matchers.flow.willThrow
+import net.corda.testing.internal.matchers.flow.willThrow
 import net.corda.core.flows.mixins.WithMockNet
 import net.corda.core.identity.CordaX500Name
 import net.corda.core.identity.Party
@@ -16,6 +16,7 @@ import net.corda.core.internal.hash
 import net.corda.node.services.persistence.NodeAttachmentService
 import net.corda.testing.core.ALICE_NAME
 import net.corda.testing.core.BOB_NAME
+import net.corda.testing.core.makeUnique
 import net.corda.testing.core.singleIdentity
 import net.corda.testing.node.internal.InternalMockNetwork
 import net.corda.testing.node.internal.InternalMockNodeParameters
@@ -120,13 +121,13 @@ class AttachmentTests : WithMockNet {
 
     //region Generators
     override fun makeNode(name: CordaX500Name) =
-        mockNet.createPartyNode(randomise(name)).apply {
+        mockNet.createPartyNode(makeUnique(name)).apply {
             registerInitiatedFlow(FetchAttachmentsResponse::class.java)
         }
 
     // Makes a node that doesn't do sanity checking at load time.
     private fun makeBadNode(name: CordaX500Name) = mockNet.createNode(
-            InternalMockNodeParameters(legalName = randomise(name)),
+            InternalMockNodeParameters(legalName = makeUnique(name)),
             nodeFactory = { args, _ ->
                 object : InternalMockNetwork.MockNode(args) {
                     override fun start() = super.start().apply { attachments.checkAttachmentsOnLoad = false }

core/src/test/kotlin/net/corda/core/flows/CollectSignaturesFlowTests.kt

@@ -5,8 +5,8 @@ import com.natpryce.hamkrest.assertion.assert
 import net.corda.core.contracts.Command
 import net.corda.core.contracts.StateAndContract
 import net.corda.core.contracts.requireThat
-import net.corda.core.flows.matchers.flow.willReturn
+import net.corda.testing.internal.matchers.flow.willReturn
-import net.corda.core.flows.matchers.flow.willThrow
+import net.corda.testing.internal.matchers.flow.willThrow
 import net.corda.core.flows.mixins.WithContracts
 import net.corda.core.identity.CordaX500Name
 import net.corda.core.identity.Party

core/src/test/kotlin/net/corda/core/flows/ContractUpgradeFlowRPCTest.kt

@@ -8,8 +8,8 @@ import com.natpryce.hamkrest.isA
 import net.corda.core.CordaRuntimeException
 import net.corda.core.contracts.ContractState
 import net.corda.core.contracts.StateAndRef
-import net.corda.core.flows.matchers.rpc.willReturn
+import net.corda.testing.internal.matchers.rpc.willReturn
-import net.corda.core.flows.matchers.rpc.willThrow
+import net.corda.testing.internal.matchers.rpc.willThrow
 import net.corda.core.flows.mixins.WithContracts
 import net.corda.core.flows.mixins.WithFinality
 import net.corda.core.messaging.CordaRPCOps

core/src/test/kotlin/net/corda/core/flows/ContractUpgradeFlowTest.kt

@@ -3,8 +3,8 @@ package net.corda.core.flows
 import com.natpryce.hamkrest.*
 import com.natpryce.hamkrest.assertion.assert
 import net.corda.core.contracts.*
-import net.corda.core.flows.matchers.flow.willReturn
+import net.corda.testing.internal.matchers.flow.willReturn
-import net.corda.core.flows.matchers.flow.willThrow
+import net.corda.testing.internal.matchers.flow.willThrow
 import net.corda.core.flows.mixins.WithContracts
 import net.corda.core.flows.mixins.WithFinality
 import net.corda.core.identity.AbstractParty
@@ -80,9 +80,9 @@ class ContractUpgradeFlowTest : WithContracts, WithFinality {
         // Party A initiates contract upgrade flow, expected to succeed this time.
         assert.that(
             aliceNode.initiateDummyContractUpgrade(atx),
-            willReturn(
+                willReturn(
-                aliceNode.hasDummyContractUpgradeTransaction()
+                        aliceNode.hasDummyContractUpgradeTransaction()
-                and bobNode.hasDummyContractUpgradeTransaction()))
+                                and bobNode.hasDummyContractUpgradeTransaction()))
     }
 
     private fun TestStartedNode.issueCash(amount: Amount<Currency> = Amount(1000, USD)) =

core/src/test/kotlin/net/corda/core/flows/FinalityFlowTests.kt

@@ -2,8 +2,8 @@ package net.corda.core.flows
 
 import com.natpryce.hamkrest.and
 import com.natpryce.hamkrest.assertion.assert
-import net.corda.core.flows.matchers.flow.willReturn
+import net.corda.testing.internal.matchers.flow.willReturn
-import net.corda.core.flows.matchers.flow.willThrow
+import net.corda.testing.internal.matchers.flow.willThrow
 import net.corda.core.flows.mixins.WithFinality
 import net.corda.core.identity.Party
 import net.corda.core.transactions.SignedTransaction

core/src/test/kotlin/net/corda/core/flows/ReceiveAllFlowTests.kt

@@ -2,7 +2,7 @@ package net.corda.core.flows
 
 import co.paralleluniverse.fibers.Suspendable
 import com.natpryce.hamkrest.assertion.assert
-import net.corda.core.flows.matchers.flow.willReturn
+import net.corda.testing.internal.matchers.flow.willReturn
 import net.corda.core.flows.mixins.WithMockNet
 import net.corda.core.identity.Party
 import net.corda.core.utilities.UntrustworthyData

core/src/test/kotlin/net/corda/core/flows/matchers/flow/FlowMatchers.kt

@@ -1,36 +0,0 @@
-package net.corda.core.flows.matchers.flow
-
-import com.natpryce.hamkrest.Matcher
-import com.natpryce.hamkrest.equalTo
-import com.natpryce.hamkrest.has
-import net.corda.core.flows.matchers.willReturn
-import net.corda.core.flows.matchers.willThrow
-import net.corda.core.internal.FlowStateMachine
-
-/**
- * Matches a Flow that succeeds with a result matched by the given matcher
- */
-fun <T> willReturn() = has(FlowStateMachine<T>::resultFuture, willReturn())
-
-fun <T> willReturn(expected: T): Matcher<FlowStateMachine<out T?>> = net.corda.core.flows.matchers.flow.willReturn(equalTo(expected))
-
-/**
- * Matches a Flow that succeeds with a result matched by the given matcher
- */
-fun <T> willReturn(successMatcher: Matcher<T>) = has(
-        FlowStateMachine<out T>::resultFuture,
-        willReturn(successMatcher))
-
-/**
- * Matches a Flow that fails, with an exception matched by the given matcher.
- */
-inline fun <reified E: Exception> willThrow(failureMatcher: Matcher<E>) = has(
-        FlowStateMachine<*>::resultFuture,
-        willThrow(failureMatcher))
-
-/**
- * Matches a Flow that fails, with an exception of the specified type.
- */
-inline fun <reified E: Exception> willThrow() = has(
-        FlowStateMachine<*>::resultFuture,
-        willThrow<E>())

core/src/test/kotlin/net/corda/core/flows/matchers/rpc/RpcMatchers.kt

@@ -1,31 +0,0 @@
-package net.corda.core.flows.matchers.rpc
-
-import com.natpryce.hamkrest.Matcher
-import com.natpryce.hamkrest.has
-import net.corda.core.flows.matchers.willReturn
-import net.corda.core.flows.matchers.willThrow
-import net.corda.core.messaging.FlowHandle
-
-/**
- * Matches a flow handle that succeeds with a result matched by the given matcher
- */
-fun <T> willReturn() = has(FlowHandle<T>::returnValue, willReturn())
-
-/**
- * Matches a flow handle that succeeds with a result matched by the given matcher
- */
-fun <T> willReturn(successMatcher: Matcher<T>) = has(FlowHandle<out T>::returnValue, willReturn(successMatcher))
-
-/**
- * Matches a flow handle that fails, with an exception matched by the given matcher.
- */
-inline fun <reified E: Exception> willThrow(failureMatcher: Matcher<E>) = has(
-    FlowHandle<*>::returnValue,
-        willThrow(failureMatcher))
-
-/**
- * Matches a flow handle that fails, with an exception of the specified type.
- */
-inline fun <reified E: Exception> willThrow() = has(
-    FlowHandle<*>::returnValue,
-        willThrow<E>())

core/src/test/kotlin/net/corda/core/flows/mixins/WithMockNet.kt

@@ -9,10 +9,10 @@ import net.corda.core.identity.PartyAndCertificate
 import net.corda.core.internal.FlowStateMachine
 import net.corda.core.transactions.SignedTransaction
 import net.corda.core.transactions.TransactionBuilder
+import net.corda.testing.core.makeUnique
 import net.corda.testing.node.internal.InternalMockNetwork
 import net.corda.testing.node.internal.TestStartedNode
 import net.corda.testing.node.internal.startFlow
-import java.util.*
 import kotlin.reflect.KClass
 
 /**
@@ -25,12 +25,7 @@ interface WithMockNet {
     /**
      * Create a node using a randomised version of the given name
      */
-    fun makeNode(name: CordaX500Name) = mockNet.createPartyNode(randomise(name))
+    fun makeNode(name: CordaX500Name) = mockNet.createPartyNode(makeUnique(name))
-
-    /**
-     * Randomise a party name to avoid clashes with other tests
-     */
-    fun randomise(name: CordaX500Name) = name.copy(commonName = "${name.commonName}_${UUID.randomUUID()}")
 
     /**
      * Run the mock network before proceeding

testing/node-driver/src/main/kotlin/net/corda/testing/node/internal/InternalMockNetwork.kt

@@ -337,7 +337,7 @@ open class InternalMockNetwork(defaultParameters: MockNetworkParameters = MockNe
                 }
             }
 
-        override val started: TestStartedNode? get() = uncheckedCast(super.started)
+        override val started: TestStartedNode? get() = super.started
 
         override fun createStartedNode(nodeInfo: NodeInfo, rpcOps: CordaRPCOps, notaryService: NotaryService?): TestStartedNode {
             return TestStartedNodeImpl(

testing/test-utils/build.gradle

@@ -24,6 +24,7 @@ dependencies {
     compile 'com.nhaarman:mockito-kotlin:1.5.0'
     compile "org.mockito:mockito-core:$mockito_version"
     compile "org.assertj:assertj-core:$assertj_version"
+    compile "com.natpryce:hamkrest:$hamkrest_version"
 
     // Guava: Google test library (collections test suite)
     compile "com.google.guava:guava-testlib:$guava_version"

testing/test-utils/src/main/kotlin/net/corda/testing/core/TestUtils.kt

@@ -25,6 +25,7 @@ import java.math.BigInteger
 import java.security.KeyPair
 import java.security.PublicKey
 import java.security.cert.X509Certificate
+import java.util.*
 import java.util.concurrent.atomic.AtomicInteger
 
 /**
@@ -108,6 +109,18 @@ fun getTestPartyAndCertificate(name: CordaX500Name, publicKey: PublicKey): Party
     return getTestPartyAndCertificate(Party(name, publicKey))
 }
 
+
+private val count = AtomicInteger(0)
+/**
+ * Randomise a party name to avoid clashes with other tests
+ */
+fun makeUnique(name: CordaX500Name) = name.copy(commonName =
+    if (name.commonName == null) {
+        count.incrementAndGet().toString()
+    } else {
+        "${ name.commonName }_${ count.incrementAndGet() }"
+    })
+
 /**
  * A class that encapsulates a test identity containing a [CordaX500Name] and a [KeyPair], alongside a range
  * of utility methods for use during testing.

testing/test-utils/src/main/kotlin/net/corda/testing/internal/matchers/Matchers.kt

@@ -0,0 +1,99 @@
+package net.corda.testing.internal.matchers
+
+import com.natpryce.hamkrest.*
+
+internal fun indent(description: String) = description.lineSequence().map { "\t$it" }.joinToString("\n")
+
+fun hasEntrySetSize(expected: Int) = object : Matcher<Map<*, *>> {
+    override val description = "is a map of size $expected"
+    override fun invoke(actual: Map<*, *>) =
+        if (actual.size == expected) {
+            MatchResult.Match
+        } else {
+            MatchResult.Mismatch("was a map of size ${actual.size}")
+        }
+}
+
+fun <T> Matcher<T>.redescribe(redescriber: (String) -> String) = object : Matcher<T> {
+    override val description = redescriber(this@redescribe.description)
+    override fun invoke(actual: T) = this@redescribe(actual)
+}
+
+fun <T> Matcher<T>.redescribeMismatch(redescriber: (String) -> String) = object : Matcher<T> {
+    override val description = this@redescribeMismatch.description
+    override fun invoke(actual: T) = this@redescribeMismatch(actual).modifyMismatchDescription(redescriber)
+}
+
+fun MatchResult.modifyMismatchDescription(modify: (String) -> String) = when(this) {
+    is MatchResult.Match -> MatchResult.Match
+    is MatchResult.Mismatch -> MatchResult.Mismatch(modify(this.description))
+}
+
+fun <O, I> Matcher<I>.extrude(projection: (O) -> I) = object : Matcher<O> {
+    override val description = this@extrude.description
+    override fun invoke(actual: O) = this@extrude(projection(actual))
+}
+
+internal fun <K, V> hasAnEntry(key: K, valueMatcher: Matcher<V>) = object : Matcher<Map<K, V>> {
+    override val description = "$key: ${valueMatcher.description}"
+    override fun invoke(actual: Map<K, V>): MatchResult =
+            actual[key]?.let { valueMatcher(it) }?.let { when(it) {
+                is MatchResult.Match -> it
+                is MatchResult.Mismatch -> MatchResult.Mismatch("$key: ${it.description}")
+            }} ?: MatchResult.Mismatch("$key was not present")
+}
+
+fun <K, V> hasEntry(key: K, valueMatcher: Matcher<V>) =
+        hasAnEntry(key, valueMatcher).redescribe { "Is a map containing the entry:\n${indent(it)}"}
+
+fun <K, V> hasOnlyEntries(vararg entryMatchers: Pair<K, Matcher<V>>) = hasOnlyEntries(entryMatchers.toList())
+
+fun <K, V> hasOnlyEntries(entryMatchers: Collection<Pair<K, Matcher<V>>>) =
+        allOf(
+                hasEntrySetSize(entryMatchers.size),
+                hasEntries(entryMatchers)
+        )
+
+fun <K, V> hasEntries(vararg entryMatchers: Pair<K, Matcher<V>>) = hasEntries(entryMatchers.toList())
+
+fun <K, V> hasEntries(entryMatchers: Collection<Pair<K, Matcher<V>>>) = object : Matcher<Map<K, V>> {
+    override val description =
+            "is a map containing the entries:\n" +
+                    entryMatchers.asSequence()
+                        .joinToString("\n") { indent("${it.first}: ${it.second.description}") }
+
+    override fun invoke(actual: Map<K, V>): MatchResult {
+        val mismatches = entryMatchers.map { hasAnEntry(it.first, it.second)(actual) }
+                .filterIsInstance<MatchResult.Mismatch>()
+
+        return if (mismatches.isEmpty()) {
+            MatchResult.Match
+        } else {
+            MatchResult.Mismatch(
+                    "had entries which did not meet criteria:\n" +
+                            mismatches.joinToString("\n") { indent(it.description) })
+        }
+    }
+}
+
+fun <T> allOf(vararg matchers: Matcher<T>) = allOf(matchers.toList())
+
+fun <T> allOf(matchers: Collection<Matcher<T>>) = object : Matcher<T> {
+    override val description =
+            "meets all of the criteria:\n" +
+                    matchers.asSequence()
+                            .joinToString("\n") { indent(it.description) }
+
+    override fun invoke(actual: T) : MatchResult {
+        val mismatches = matchers.map { it(actual) }
+                .filterIsInstance<MatchResult.Mismatch>()
+
+        return if (mismatches.isEmpty()) {
+            MatchResult.Match
+        } else {
+            MatchResult.Mismatch(
+                    "did not meet criteria:\n" +
+                            mismatches.joinToString("\n") { indent(it.description) })
+        }
+    }
+}

testing/test-utils/src/main/kotlin/net/corda/testing/internal/matchers/flow/FlowMatchers.kt

@@ -0,0 +1,38 @@
+package net.corda.testing.internal.matchers.flow
+
+import com.natpryce.hamkrest.Matcher
+import com.natpryce.hamkrest.equalTo
+import net.corda.core.internal.FlowStateMachine
+import net.corda.testing.internal.matchers.*
+
+/**
+ * Matches a Flow that succeeds with a result matched by the given matcher
+ */
+fun <T> willReturn(): Matcher<FlowStateMachine<T>> = net.corda.testing.internal.matchers.future.willReturn<T>()
+        .extrude(FlowStateMachine<T>::resultFuture)
+        .redescribe { "is a flow that will return" }
+
+fun <T> willReturn(expected: T): Matcher<FlowStateMachine<T>> = willReturn(equalTo(expected))
+
+/**
+ * Matches a Flow that succeeds with a result matched by the given matcher
+ */
+fun <T> willReturn(successMatcher: Matcher<T>) = net.corda.testing.internal.matchers.future.willReturn(successMatcher)
+        .extrude(FlowStateMachine<out T>::resultFuture)
+        .redescribe { "is a flow that will return with a value that ${successMatcher.description}" }
+
+/**
+ * Matches a Flow that fails, with an exception matched by the given matcher.
+ */
+inline fun <reified E: Exception> willThrow(failureMatcher: Matcher<E>) =
+        net.corda.testing.internal.matchers.future.willThrow(failureMatcher)
+            .extrude(FlowStateMachine<*>::resultFuture)
+            .redescribe { "is a flow that will fail, throwing an exception that ${failureMatcher.description}" }
+
+/**
+ * Matches a Flow that fails, with an exception of the specified type.
+ */
+inline fun <reified E: Exception> willThrow() =
+        net.corda.testing.internal.matchers.future.willThrow<E>()
+                .extrude(FlowStateMachine<*>::resultFuture)
+                .redescribe { "is a flow that will fail with an exception of type ${E::class.java.simpleName}" }

testing/test-utils/src/main/kotlin/net/corda/testing/internal/matchers/future/FutureMatchers.kt

@@ -1,9 +1,10 @@
-package net.corda.core.flows.matchers
+package net.corda.testing.internal.matchers.future
 
 import com.natpryce.hamkrest.MatchResult
 import com.natpryce.hamkrest.Matcher
 import com.natpryce.hamkrest.equalTo
 import net.corda.core.utilities.getOrThrow
+import net.corda.testing.internal.matchers.modifyMismatchDescription
 import java.util.concurrent.Future
 
 /**
@@ -16,7 +17,7 @@ fun <T> willReturn() = object : Matcher<Future<T>> {
         actual.getOrThrow()
         MatchResult.Match
     } catch (e: Exception) {
-        MatchResult.Mismatch("Failed with $e")
+        MatchResult.Mismatch("failed with $e")
     }
 }
 
@@ -29,9 +30,9 @@ fun <T> willReturn(successMatcher: Matcher<T>) = object : Matcher<Future<out T>>
     override val description: String = "is a future that will succeed with a value that ${successMatcher.description}"
 
     override fun invoke(actual: Future<out T>): MatchResult = try {
-        successMatcher(actual.getOrThrow())
+        successMatcher(actual.getOrThrow()).modifyMismatchDescription { "succeeded with value that $it" }
     } catch (e: Exception) {
-        MatchResult.Mismatch("Failed with $e")
+        MatchResult.Mismatch("failed with $e")
     }
 }
 
@@ -44,11 +45,11 @@ inline fun <reified E: Exception> willThrow(failureMatcher: Matcher<E>) = object
 
     override fun invoke(actual: Future<*>): MatchResult = try {
         actual.getOrThrow()
-        MatchResult.Mismatch("Succeeded")
+        MatchResult.Mismatch("succeeded")
     } catch (e: Exception) {
         when(e) {
-            is E -> failureMatcher(e)
+            is E -> failureMatcher(e).modifyMismatchDescription { "failed with ${E::class.java.simpleName} that $it" }
-            else -> MatchResult.Mismatch("Failure class was ${e.javaClass}")
+            else -> MatchResult.Mismatch("failed with ${e.javaClass}")
         }
     }
 }
@@ -62,11 +63,11 @@ inline fun <reified E: Exception> willThrow() = object : Matcher<Future<*>> {
 
     override fun invoke(actual: Future<*>): MatchResult = try {
         actual.getOrThrow()
-        MatchResult.Mismatch("Succeeded")
+        MatchResult.Mismatch("succeeded")
     } catch (e: Exception) {
         when(e) {
             is E -> MatchResult.Match
-            else -> MatchResult.Mismatch("Failure class was ${e.javaClass}")
+            else -> MatchResult.Mismatch("failed with ${e.javaClass}")
         }
     }
 }

testing/test-utils/src/main/kotlin/net/corda/testing/internal/matchers/rpc/RpcMatchers.kt

@@ -0,0 +1,36 @@
+package net.corda.testing.internal.matchers.rpc
+
+import com.natpryce.hamkrest.Matcher
+import net.corda.core.messaging.FlowHandle
+import net.corda.testing.internal.matchers.extrude
+import net.corda.testing.internal.matchers.redescribe
+
+/**
+ * Matches a flow handle that succeeds with a result matched by the given matcher
+ */
+fun <T> willReturn() = net.corda.testing.internal.matchers.future.willReturn<T>()
+        .extrude(FlowHandle<T>::returnValue)
+        .redescribe { "is an RPG flow handle that will return" }
+
+/**
+ * Matches a flow handle that succeeds with a result matched by the given matcher
+ */
+fun <T> willReturn(successMatcher: Matcher<T>) = net.corda.testing.internal.matchers.future.willReturn(successMatcher)
+        .extrude(FlowHandle<T>::returnValue)
+        .redescribe { "is an RPG flow handle that will return a value that ${successMatcher.description}" }
+
+/**
+ * Matches a flow handle that fails, with an exception matched by the given matcher.
+ */
+inline fun <reified E: Exception> willThrow(failureMatcher: Matcher<E>) =
+        net.corda.testing.internal.matchers.future.willThrow(failureMatcher)
+        .extrude(FlowHandle<*>::returnValue)
+        .redescribe { "is an RPG flow handle that will fail with an exception that ${failureMatcher.description}" }
+
+/**
+ * Matches a flow handle that fails, with an exception of the specified type.
+ */
+inline fun <reified E: Exception> willThrow() =
+        net.corda.testing.internal.matchers.future.willThrow<E>()
+        .extrude(FlowHandle<*>::returnValue)
+        .redescribe { "is an RPG flow handle that will fail with an exception of type ${E::class.java.simpleName}" }

testing/test-utils/src/test/kotlin/net/corda/testing/internal/MatcherTests.kt

@@ -0,0 +1,58 @@
+package net.corda.testing.internal
+
+import com.natpryce.hamkrest.MatchResult
+import com.natpryce.hamkrest.equalTo
+import net.corda.testing.internal.matchers.hasEntries
+import org.junit.Test
+import kotlin.test.assertEquals
+
+class MatcherTests {
+    @Test
+    fun `nested items indent`() {
+        val nestedMap = mapOf(
+                "a" to mapOf(
+                        "apple" to "vegetable",
+                        "aardvark" to "animal",
+                        "anthracite" to "mineral"),
+                "b" to mapOf(
+                        "broccoli" to "mineral",
+                        "bison" to "animal",
+                        "bauxite" to "vegetable")
+                )
+
+        val matcher = hasEntries(
+                "a" to hasEntries(
+                        "aardvark" to equalTo("animal"),
+                        "anthracite" to equalTo("mineral")
+                ),
+                "b" to hasEntries(
+                        "bison" to equalTo("animal"),
+                        "bauxite" to equalTo("mineral")
+                )
+        )
+
+        println(matcher.description)
+        println((matcher(nestedMap) as MatchResult.Mismatch).description)
+
+        assertEquals(
+                """
+                is a map containing the entries:
+                    a: is a map containing the entries:
+                        aardvark: is equal to "animal"
+                        anthracite: is equal to "mineral"
+                    b: is a map containing the entries:
+                        bison: is equal to "animal"
+                        bauxite: is equal to "mineral"
+                """.trimIndent().replace("    ", "\t"),
+                matcher.description)
+
+        assertEquals(
+                """
+                had entries which did not meet criteria:
+                    b: had entries which did not meet criteria:
+                        bauxite: was: "vegetable"
+                """.trimIndent().replace("    ", "\t"),
+                (matcher(nestedMap) as MatchResult.Mismatch).description
+        )
+    }
+}