Clarify test intention with generators, operations and matchers

core/build.gradle

@@ -68,6 +68,9 @@ dependencies {
     compile "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
     testCompile "org.jetbrains.kotlin:kotlin-test:$kotlin_version"
 
+    // Hamkrest, for fluent, composable matchers
+    testCompile 'com.natpryce:hamkrest:1.4.2.2'
+
     // Quasar, for suspendable fibres.
     compileOnly "$quasar_group:quasar-core:$quasar_version:jdk8"
 

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

@@ -1,6 +1,7 @@
 package net.corda.core.flows
 
 import co.paralleluniverse.fibers.Suspendable
+import com.natpryce.hamkrest.*
 import net.corda.core.contracts.Attachment
 import net.corda.core.crypto.SecureHash
 import net.corda.core.identity.CordaX500Name
@@ -8,7 +9,6 @@ import net.corda.core.identity.Party
 import net.corda.core.internal.FetchAttachmentsFlow
 import net.corda.core.internal.FetchDataFlow
 import net.corda.core.internal.hash
-import net.corda.core.utilities.getOrThrow
 import net.corda.node.internal.StartedNode
 import net.corda.node.services.persistence.NodeAttachmentService
 import net.corda.testing.core.ALICE_NAME
@@ -23,8 +23,8 @@ import java.io.ByteArrayOutputStream
 import java.util.*
 import java.util.jar.JarOutputStream
 import java.util.zip.ZipEntry
-import kotlin.test.assertEquals
-import kotlin.test.assertFailsWith
+import com.natpryce.hamkrest.assertion.assert
+import net.corda.core.matchers.*
 
 class AttachmentTests {
     companion object {
@@ -35,103 +35,68 @@ class AttachmentTests {
         fun cleanUp() = mockNet.stopNodes()
     }
 
-    private fun fakeAttachment(): ByteArray {
-        val bs = ByteArrayOutputStream()
-        val js = JarOutputStream(bs)
-        js.putNextEntry(ZipEntry("file1.txt"))
-        js.writer().apply { append("Some useful content"); flush() }
-        js.closeEntry()
-        js.close()
-        return bs.toByteArray()
-    }
-
-    private fun createAlice() = mockNet.createPartyNode(randomiseName(ALICE_NAME))
-    private fun createBob() = mockNet.createPartyNode(randomiseName(BOB_NAME))
-    private fun randomiseName(name: CordaX500Name) = name.copy(commonName = "${name.commonName}_${UUID.randomUUID()}")
+    // Test nodes
+    private val aliceNode = makeNode(ALICE_NAME)
+    private val bobNode = makeNode(BOB_NAME)
+    private val alice = aliceNode.info.singleIdentity()
 
     @Test
     fun `download and store`() {
-        val aliceNode = createAlice()
-        val bobNode = createBob()
-        val alice = aliceNode.info.singleIdentity()
-        aliceNode.registerInitiatedFlow(FetchAttachmentsResponse::class.java)
-        bobNode.registerInitiatedFlow(FetchAttachmentsResponse::class.java)
         // Insert an attachment into node zero's store directly.
-        val id = aliceNode.database.transaction {
-            aliceNode.attachments.importAttachment(fakeAttachment().inputStream(), "test", null)
-        }
+        val id = aliceNode.importAttachment(fakeAttachment())
 
         // Get node one to run a flow to fetch it and insert it.
-        mockNet.runNetwork()
-        val bobFlow = bobNode.startAttachmentFlow(setOf(id), alice)
-        mockNet.runNetwork()
-        assertEquals(0, bobFlow.resultFuture.getOrThrow().fromDisk.size)
+        assert.that(
+            bobNode.startAttachmentFlow(id, alice),
+            succeedsWith(noAttachments()))
 
         // Verify it was inserted into node one's store.
-        val attachment = bobNode.database.transaction {
-            bobNode.attachments.openAttachment(id)!!
-        }
-
-        assertEquals(id, attachment.open().hash())
+        val attachment = bobNode.getAttachmentWithId(id)
+        assert.that(attachment, hashesTo(id))
 
         // Shut down node zero and ensure node one can still resolve the attachment.
         aliceNode.dispose()
 
-        val response: FetchDataFlow.Result<Attachment> = bobNode.startAttachmentFlow(setOf(id), alice).resultFuture.getOrThrow()
-        assertEquals(attachment, response.fromDisk[0])
+        assert.that(
+            bobNode.startAttachmentFlow(id, alice),
+            succeedsWith(soleAttachment(attachment)))
     }
 
     @Test
     fun missing() {
-        val aliceNode = createAlice()
-        val bobNode = createBob()
-        aliceNode.registerInitiatedFlow(FetchAttachmentsResponse::class.java)
-        bobNode.registerInitiatedFlow(FetchAttachmentsResponse::class.java)
+        val hash: SecureHash = SecureHash.randomSHA256()
+
         // Get node one to fetch a non-existent attachment.
-        val hash = SecureHash.randomSHA256()
-        val alice = aliceNode.info.singleIdentity()
-        val bobFlow = bobNode.startAttachmentFlow(setOf(hash), alice)
-        mockNet.runNetwork()
-        val e = assertFailsWith<FetchDataFlow.HashNotFound> { bobFlow.resultFuture.getOrThrow() }
-        assertEquals(hash, e.requested)
+        assert.that(
+            bobNode.startAttachmentFlow(hash, alice),
+            failsWith<FetchDataFlow.HashNotFound>(
+                has("requested hash", { it.requested }, equalTo(hash))))
     }
 
     @Test
     fun maliciousResponse() {
         // Make a node that doesn't do sanity checking at load time.
-        val aliceNode = mockNet.createNode(InternalMockNodeParameters(legalName = randomiseName(ALICE_NAME)), nodeFactory = { args ->
-            object : InternalMockNetwork.MockNode(args) {
-                override fun start() = super.start().apply { attachments.checkAttachmentsOnLoad = false }
-            }
-        })
-        val bobNode = mockNet.createNode(InternalMockNodeParameters(legalName = randomiseName(BOB_NAME)))
-        val alice = aliceNode.info.singleIdentity()
-        aliceNode.registerInitiatedFlow(FetchAttachmentsResponse::class.java)
-        bobNode.registerInitiatedFlow(FetchAttachmentsResponse::class.java)
-        val attachment = fakeAttachment()
+        val badAliceNode = makeBadNode(ALICE_NAME)
+        val badAlice = badAliceNode.info.singleIdentity()
+
         // Insert an attachment into node zero's store directly.
-        val id = aliceNode.database.transaction {
-            aliceNode.attachments.importAttachment(attachment.inputStream(), "test", null)
-        }
+        val attachment = fakeAttachment()
+        val id = badAliceNode.importAttachment(attachment)
 
         // Corrupt its store.
         val corruptBytes = "arggghhhh".toByteArray()
         System.arraycopy(corruptBytes, 0, attachment, 0, corruptBytes.size)
 
         val corruptAttachment = NodeAttachmentService.DBAttachment(attId = id.toString(), content = attachment)
-        aliceNode.database.transaction {
-            session.update(corruptAttachment)
-        }
+        badAliceNode.updateAttachment(corruptAttachment)
 
         // Get n1 to fetch the attachment. Should receive corrupted bytes.
-        mockNet.runNetwork()
-        val bobFlow = bobNode.startAttachmentFlow(setOf(id), alice)
-        mockNet.runNetwork()
-        assertFailsWith<FetchDataFlow.DownloadedVsRequestedDataMismatch> { bobFlow.resultFuture.getOrThrow() }
+        assert.that(
+            bobNode.startAttachmentFlow(id, badAlice),
+            failsWith<FetchDataFlow.DownloadedVsRequestedDataMismatch>()
+        )
     }
 
-    private fun StartedNode<*>.startAttachmentFlow(hashes: Set<SecureHash>, otherSide: Party) = services.startFlow(InitiatingFetchAttachmentsFlow(otherSide, hashes))
-
     @InitiatingFlow
     private class InitiatingFetchAttachmentsFlow(val otherSide: Party, val hashes: Set<SecureHash>) : FlowLogic<FetchDataFlow.Result<Attachment>>() {
         @Suspendable
@@ -146,4 +111,69 @@ class AttachmentTests {
         @Suspendable
         override fun call() = subFlow(TestDataVendingFlow(otherSideSession))
     }
+
+    //region Generators
+    private fun makeNode(name: CordaX500Name) =
+        mockNet.createPartyNode(randomiseName(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 = randomiseName(name)),
+            nodeFactory = { args ->
+                object : InternalMockNetwork.MockNode(args) {
+                    override fun start() = super.start().apply { attachments.checkAttachmentsOnLoad = false }
+                }
+            }).apply { registerInitiatedFlow(FetchAttachmentsResponse::class.java) }
+
+    private fun randomiseName(name: CordaX500Name) = name.copy(commonName = "${name.commonName}_${UUID.randomUUID()}")
+
+    private fun fakeAttachment(): ByteArray =
+        ByteArrayOutputStream().use { baos ->
+            JarOutputStream(baos).use { jos ->
+                jos.putNextEntry(ZipEntry("file1.txt"))
+                jos.writer().apply {
+                    append("Some useful content")
+                    flush()
+                }
+                jos.closeEntry()
+            }
+            baos.toByteArray()
+        }
+    //endregion
+
+    //region Operations
+    private fun StartedNode<*>.importAttachment(attachment: ByteArray) = database.transaction {
+        attachments.importAttachment(attachment.inputStream(), "test", null)
+    }.andRunNetwork()
+
+    private fun StartedNode<*>.updateAttachment(attachment:  NodeAttachmentService.DBAttachment) =
+            database.transaction { session.update(attachment) }.andRunNetwork()
+
+    private fun StartedNode<*>.startAttachmentFlow(hash: SecureHash, otherSide: Party) = services.startFlow(
+            InitiatingFetchAttachmentsFlow(otherSide, setOf(hash))).andRunNetwork()
+
+    private fun StartedNode<*>.getAttachmentWithId(id: SecureHash) = database.transaction {
+        attachments.openAttachment(id)!!
+    }
+
+    private fun <T : Any> T.andRunNetwork(): T {
+        mockNet.runNetwork()
+        return this
+    }
+    //endregion
+
+    //region Matchers
+    private fun noAttachments() = has(FetchDataFlow.Result<Attachment>::fromDisk, isEmpty)
+    private fun soleAttachment(attachment: Attachment) = has(FetchDataFlow.Result<Attachment>::fromDisk,
+            hasSize(equalTo(1)) and
+                    hasElement(attachment))
+
+    private fun hashesTo(hash: SecureHash) = has<Attachment, SecureHash>(
+        "hash",
+        { it.open().hash() },
+        equalTo(hash))
+    //endregion
+
 }

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

@@ -0,0 +1,56 @@
+package net.corda.core.matchers
+
+import com.natpryce.hamkrest.MatchResult
+import com.natpryce.hamkrest.Matcher
+import net.corda.core.internal.FlowStateMachine
+import net.corda.core.utilities.getOrThrow
+
+/**
+ * Matches a Flow that succeeds with a result matched by the given matcher
+ */
+fun <T> succeedsWith(successMatcher: Matcher<T>) = object : Matcher<FlowStateMachine<T>> {
+    override val description: String
+        get() = "A flow that succeeds with ${successMatcher.description}"
+
+    override fun invoke(actual: FlowStateMachine<T>): MatchResult = try {
+        successMatcher(actual.resultFuture.getOrThrow())
+    } catch (e: Exception) {
+        MatchResult.Mismatch("Failed with $e")
+    }
+}
+
+/**
+ * Matches a Flow that fails, with an exception matched by the given matcher.
+ */
+inline fun <reified E: Exception> failsWith(failureMatcher: Matcher<E>) = object : Matcher<FlowStateMachine<*>> {
+    override val description: String
+        get() = "A flow that fails with a ${E::class.java} that ${failureMatcher.description}"
+
+    override fun invoke(actual: FlowStateMachine<*>): MatchResult = try {
+        actual.resultFuture.getOrThrow()
+        MatchResult.Mismatch("Succeeded")
+    } catch (e: Exception) {
+        when(e) {
+            is E -> failureMatcher(e)
+            else -> MatchResult.Mismatch("Failure class was ${e.javaClass}")
+        }
+    }
+}
+
+/**
+ * Matches a Flow that fails, with an exception of the specified type.
+ */
+inline fun <reified E: Exception> failsWith() = object : Matcher<FlowStateMachine<*>> {
+    override val description: String
+        get() = "A flow that fails with a ${E::class.java}"
+
+    override fun invoke(actual: FlowStateMachine<*>): MatchResult = try {
+        actual.resultFuture.getOrThrow()
+        MatchResult.Mismatch("Succeeded")
+    } catch (e: Exception) {
+        when(e) {
+            is E -> MatchResult.Match
+            else -> MatchResult.Mismatch("Failure class was ${e.javaClass}")
+        }
+    }
+}