Adds an example for an E2E system test that leverages Kafka for JUnit

gtd-command-side/src/main/java/net/mguenther/gtd/api/ItemsCommandResource.java

@@ -14,6 +14,7 @@ import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.RestController;
 
+import java.net.URI;
 import java.util.concurrent.CompletableFuture;
 
 /**
@@ -37,9 +38,11 @@ public class ItemsCommandResource {
 
         log.info("Received a create item request with data {}.", createItem);
 
+        ItemCommand createItemCommand = commandsFor(createItem);
+
         return commandHandler
-                .onCommand(commandsFor(createItem))
-                .thenApply(dontCare -> ResponseEntity.accepted().build())
+                .onCommand(createItemCommand)
+                .thenApply(dontCare -> ResponseEntity.created(itemUri(createItemCommand.getItemId())).build())
                 .exceptionally(e -> {
                     log.warn("Caught an exception at the service boundary.", e);
                     return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
@@ -49,4 +52,8 @@ public class ItemsCommandResource {
     private ItemCommand commandsFor(final CreateItemRequest createItem) {
         return new CreateItem(createItem.getDescription());
     }
+
+    private URI itemUri(final String itemId) {
+        return URI.create("/items/" + itemId);
+    }
 }

gtd-e2e-tests/pom.xml

@@ -0,0 +1,88 @@
+<?xml version="1.0"?>
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
+         xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>net.mguenther.gtd</groupId>
+        <artifactId>gtd-parent</artifactId>
+        <version>0.1.0-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>gtd-e2e-tests</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>gtd-e2e-tests</name>
+
+    <dependencies>
+        <!-- Intra-project dependencies -->
+        <dependency>
+            <groupId>net.mguenther.gtd</groupId>
+            <artifactId>gtd-common</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>net.mguenther.gtd</groupId>
+            <artifactId>gtd-codec</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+        <!-- HTTP client -->
+        <dependency>
+            <groupId>io.github.openfeign</groupId>
+            <artifactId>feign-core</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.github.openfeign</groupId>
+            <artifactId>feign-httpclient</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.github.openfeign</groupId>
+            <artifactId>feign-slf4j</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.github.openfeign</groupId>
+            <artifactId>feign-jackson</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.github.openfeign</groupId>
+            <artifactId>feign-jaxrs</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpclient</artifactId>
+            <version>${httpclient.version}</version>
+            <exclusions>
+                <exclusion>
+                    <groupId>commons-logging</groupId>
+                    <artifactId>commons-logging</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+        <!-- Testing -->
+        <dependency>
+            <groupId>net.mguenther.kafka</groupId>
+            <artifactId>kafka-junit</artifactId>
+            <version>${kafka.junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <version>${junit.jupiter.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+            <version>${junit.jupiter.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>hamcrest-core</artifactId>
+            <version>${hamcrest.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+</project>

gtd-e2e-tests/src/main/java/net/mguenther/gtd/client/CreateItem.java

@@ -0,0 +1,24 @@
+package net.mguenther.gtd.client;
+
+/**
+ * @author Markus Günther (markus.guenther@gmail.com)
+ */
+public class CreateItem {
+
+    private final String description;
+
+    public CreateItem(final String description) {
+        this.description = description;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    @Override
+    public String toString() {
+        return "CreateItemRequest{" +
+                "description='" + description + '\'' +
+                '}';
+    }
+}

gtd-e2e-tests/src/main/java/net/mguenther/gtd/client/GettingThingsDone.java

@@ -0,0 +1,27 @@
+package net.mguenther.gtd.client;
+
+import feign.Headers;
+import feign.Param;
+import feign.RequestLine;
+import feign.Response;
+
+import java.util.List;
+
+public interface GettingThingsDone {
+
+    @RequestLine("POST /items")
+    @Headers("Content-Type: application/json")
+    Response createItem(CreateItem payload);
+
+    @RequestLine("PUT /items/{itemId}")
+    @Headers("Content-Type: application/json")
+    Response updateItem(@Param("itemId") String itemId, UpdateItem payload);
+
+    @RequestLine("GET /items/{itemId}")
+    @Headers("Accept: application/json")
+    Item getItem(@Param("itemId") String itemId);
+
+    @RequestLine("GET /items")
+    @Headers("Accept: application/json")
+    List<Item> getItems();
+}

gtd-e2e-tests/src/main/java/net/mguenther/gtd/client/Item.java

@@ -0,0 +1,53 @@
+package net.mguenther.gtd.client;
+
+import java.util.Collections;
+import java.util.Date;
+import java.util.List;
+
+/**
+ * @author Markus Günther (markus.guenther@gmail.com)
+ */
+public class Item {
+
+    private String id;
+
+    private String description;
+
+    private int requiredTime;
+
+    private Date dueDate;
+
+    private List<String> tags;
+
+    private String associatedList;
+
+    private boolean done;
+
+    public String getId() {
+        return id;
+    }
+
+    public boolean isDone() {
+        return done;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public int getRequiredTime() {
+        return requiredTime;
+    }
+
+    public Date getDueDate() {
+        return dueDate;
+    }
+
+    public List<String> getTags() {
+        return Collections.unmodifiableList(tags);
+    }
+
+    public String getAssociatedList() {
+        return associatedList;
+    }
+}

gtd-e2e-tests/src/main/java/net/mguenther/gtd/client/UpdateItem.java

@@ -0,0 +1,59 @@
+package net.mguenther.gtd.client;
+
+import java.util.List;
+
+/**
+ * @author Markus Günther (markus.guenther@gmail.com)
+ */
+public class UpdateItem {
+
+    private Long dueDate;
+
+    private Integer requiredTime;
+
+    private List<String> tags;
+
+    private String associatedList;
+
+    public Long getDueDate() {
+        return dueDate;
+    }
+
+    public void setDueDate(long dueDate) {
+        this.dueDate = dueDate;
+    }
+
+    public Integer getRequiredTime() {
+        return requiredTime;
+    }
+
+    public void setRequiredTime(int requiredTime) {
+        this.requiredTime = requiredTime;
+    }
+
+    public List<String> getTags() {
+        return tags;
+    }
+
+    public void setTags(List<String> tags) {
+        this.tags = tags;
+    }
+
+    public String getAssociatedList() {
+        return associatedList;
+    }
+
+    public void setAssociatedList(String associatedList) {
+        this.associatedList = associatedList;
+    }
+
+    @Override
+    public String toString() {
+        return "UpdateItemRequest{" +
+                "dueDate=" + dueDate +
+                ", requiredTime=" + requiredTime +
+                ", tags=" + tags +
+                ", associatedList='" + associatedList + '\'' +
+                '}';
+    }
+}

gtd-e2e-tests/src/test/java/net/mguenther/gtd/EventPublicationTest.java

@@ -0,0 +1,74 @@
+package net.mguenther.gtd;
+
+import feign.Feign;
+import feign.Logger;
+import feign.Response;
+import feign.httpclient.ApacheHttpClient;
+import feign.jackson.JacksonDecoder;
+import feign.jackson.JacksonEncoder;
+import feign.slf4j.Slf4jLogger;
+import net.mguenther.gtd.client.CreateItem;
+import net.mguenther.gtd.client.GettingThingsDone;
+import net.mguenther.gtd.domain.event.ItemCreated;
+import net.mguenther.gtd.kafka.serialization.AvroItemEvent;
+import net.mguenther.gtd.kafka.serialization.ItemEventConverter;
+import net.mguenther.gtd.kafka.serialization.ItemEventDeserializer;
+import net.mguenther.kafka.junit.ExternalKafkaCluster;
+import org.apache.kafka.clients.consumer.ConsumerConfig;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+import static net.mguenther.kafka.junit.ObserveKeyValues.on;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.equalTo;
+
+public class EventPublicationTest {
+
+    private static final String URL = "http://localhost:8765/api";
+
+    private final ItemEventConverter converter = new ItemEventConverter();
+
+    @Test
+    public void anItemCreatedEventShouldBePublishedAfterCreatingNewItem() throws Exception {
+
+        ExternalKafkaCluster kafka = ExternalKafkaCluster.at("http://localhost:9092");
+        GettingThingsDone gtd = createGetthingThingsDoneClient();
+        String itemId = extractItemId(gtd.createItem(new CreateItem("I gotta do my homework!")));
+
+        List<AvroItemEvent> publishedEvents = kafka
+                .observeValues(on("topic-getting-things-done", 1, AvroItemEvent.class)
+                        .observeFor(10, TimeUnit.SECONDS)
+                        .with(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, ItemEventDeserializer.class)
+                        .filterOnKeys(aggregateId -> aggregateId.equals(itemId)));
+
+        ItemCreated itemCreatedEvent = publishedEvents.stream()
+                .findFirst()
+                .map(converter::to)
+                .map(e -> (ItemCreated) e)
+                .orElseThrow(AssertionError::new);
+
+        assertThat(itemCreatedEvent.getItemId(), equalTo(itemId));
+        assertThat(itemCreatedEvent.getDescription(), equalTo("I gotta do my homework!"));
+    }
+
+    private GettingThingsDone createGetthingThingsDoneClient() {
+        return Feign.builder()
+                .client(new ApacheHttpClient())
+                .encoder(new JacksonEncoder())
+                .decoder(new JacksonDecoder())
+                .logger(new Slf4jLogger(GettingThingsDone.class))
+                .logLevel(Logger.Level.FULL)
+                .target(GettingThingsDone.class, URL);
+    }
+
+    private String extractItemId(final Response response) {
+        return response.headers()
+                .get("Location")
+                .stream()
+                .findFirst()
+                .map(s -> s.replace("/items/", ""))
+                .orElseThrow(AssertionError::new);
+    }
+}

gtd-query-side/src/main/java/net/mguenther/gtd/api/ItemQueryResource.java

@@ -30,7 +30,7 @@ public class ItemQueryResource {
         this.itemView = itemView;
     }
 
-    /*@RequestMapping(path = "/items/{itemId}", method = RequestMethod.GET, produces = "application/json")
+    @RequestMapping(path = "/items/{itemId}", method = RequestMethod.GET, produces = "application/json")
     public CompletableFuture<ResponseEntity<Item>> showItem(@PathVariable("itemId") String itemId) {
 
         log.info("Received a show item request for item with ID {}.", itemId);
@@ -38,5 +38,5 @@ public class ItemQueryResource {
         return itemView.getItem(itemId)
                 .thenApply(optionalItem -> optionalItem.map(ResponseEntity::ok).orElse(ResponseEntity.notFound().build()))
                 .exceptionally(e -> ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build());
-    }*/
+    }
 }

gtd-query-side/src/main/java/net/mguenther/gtd/api/ItemsQueryResource.java

@@ -42,13 +42,5 @@ public class ItemsQueryResource {
                 .exceptionally(e -> ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build());
     }
 
-    @RequestMapping(path = "/items/{itemId}", method = RequestMethod.GET, produces = "application/json")
-    public CompletableFuture<ResponseEntity<Item>> showItem(@PathVariable("itemId") String itemId) {
 
-        log.info("Received a show item request for item with ID {}.", itemId);
-
-        return itemView.getItem(itemId)
-                .thenApply(optionalItem -> optionalItem.map(ResponseEntity::ok).orElse(ResponseEntity.notFound().build()))
-                .exceptionally(e -> ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build());
-    }
 }

pom.xml

@@ -21,6 +21,7 @@
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <!-- Managed dependency versions -->
+        <kafka.junit.version>2.7.0</kafka.junit.version>
         <junit.jupiter.version>5.7.0</junit.jupiter.version>
         <junit.vintage.version>5.7.0</junit.vintage.version>
         <junit.version>4.13.1</junit.version>
@@ -31,6 +32,8 @@
         <spring-cloud.version>2020.0.0</spring-cloud.version>
         <avro.version>1.8.1</avro.version>
         <commons-lang3.version>3.5</commons-lang3.version>
+        <openfeign.version>11.0</openfeign.version>
+        <httpclient.version>4.5.13</httpclient.version>
         <!-- Plugin versions -->
         <plugin.avro.version>1.10.1</plugin.avro.version>
         <plugin.compiler.version>3.5</plugin.compiler.version>
@@ -44,6 +47,7 @@
         <module>gtd-query-side</module>
         <module>gtd-api-gateway</module>
         <module>gtd-discovery-service</module>
+        <module>gtd-e2e-tests</module>
     </modules>
 
     <build>
@@ -152,11 +156,60 @@
                 <artifactId>log4j-over-slf4j</artifactId>
                 <version>${slf4j.version}</version>
             </dependency>
+            <!-- HTTP client -->
+            <dependency>
+                <groupId>io.github.openfeign</groupId>
+                <artifactId>feign-core</artifactId>
+                <version>${openfeign.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>io.github.openfeign</groupId>
+                <artifactId>feign-httpclient</artifactId>
+                <version>${openfeign.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>io.github.openfeign</groupId>
+                <artifactId>feign-slf4j</artifactId>
+                <version>${openfeign.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>io.github.openfeign</groupId>
+                <artifactId>feign-jackson</artifactId>
+                <version>${openfeign.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>io.github.openfeign</groupId>
+                <artifactId>feign-jaxrs</artifactId>
+                <version>${openfeign.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>org.apache.httpcomponents</groupId>
+                <artifactId>httpclient</artifactId>
+                <version>${httpclient.version}</version>
+                <exclusions>
+                    <exclusion>
+                        <groupId>commons-logging</groupId>
+                        <artifactId>commons-logging</artifactId>
+                    </exclusion>
+                </exclusions>
+            </dependency>
             <!-- Testing -->
             <dependency>
-                <groupId>junit</groupId>
-                <artifactId>junit</artifactId>
-                <version>${junit.version}</version>
+                <groupId>net.mguenther.kafka</groupId>
+                <artifactId>kafka-junit</artifactId>
+                <version>${kafka.junit.version}</version>
+                <scope>test</scope>
+            </dependency>
+            <dependency>
+                <groupId>org.junit.jupiter</groupId>
+                <artifactId>junit-jupiter-api</artifactId>
+                <version>${junit.jupiter.version}</version>
+                <scope>test</scope>
+            </dependency>
+            <dependency>
+                <groupId>org.junit.jupiter</groupId>
+                <artifactId>junit-jupiter-engine</artifactId>
+                <version>${junit.jupiter.version}</version>
                 <scope>test</scope>
             </dependency>
             <dependency>