Add spock data driven test example.

build.gradle

@@ -2,6 +2,7 @@ plugins {
     id 'org.springframework.boot' version '3.0.1'
     id 'io.spring.dependency-management' version '1.1.0'
     id 'java'
+    id 'groovy'
 }
 
 targetCompatibility = '17'
@@ -14,6 +15,8 @@ repositories {
 dependencies {
     implementation 'org.springframework.boot:spring-boot-starter-web'
     testImplementation('org.springframework.boot:spring-boot-starter-test')
+    testImplementation 'org.spockframework:spock-core:2.4-M1-groovy-4.0'
+    testImplementation 'org.spockframework:spock-spring:2.4-M1-groovy-4.0'
 }
 
 test {

src/main/java/com/wilkins/showcase/ShowcaseApplication.java

@@ -2,11 +2,22 @@
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.web.servlet.ServletComponentScan;
+import org.springframework.context.annotation.Bean;
 
+import java.util.UUID;
+import java.util.function.Supplier;
+
+@ServletComponentScan
 @SpringBootApplication
 public class ShowcaseApplication {
 
     public static void main(String[] args) {
         SpringApplication.run(ShowcaseApplication.class, args);
     }
+
+    @Bean
+    public Supplier<String> randomStringSupplier() {
+        return () -> UUID.randomUUID().toString();
+    }
 }

src/main/java/com/wilkins/showcase/filters/TraceIdFilter.java

@@ -0,0 +1,26 @@
+package com.wilkins.showcase.filters;
+
+import com.wilkins.showcase.service.ExampleService;
+import jakarta.servlet.*;
+import jakarta.servlet.annotation.WebFilter;
+import jakarta.servlet.http.HttpServletResponse;
+import org.springframework.stereotype.Component;
+
+import java.io.IOException;
+
+@WebFilter("/*")
+public class TraceIdFilter implements Filter {
+
+    private final ExampleService idService;
+
+    public TraceIdFilter(ExampleService idService) {
+        this.idService = idService;
+    }
+
+    @Override
+    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
+        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
+        httpServletResponse.setHeader("x-trace-id", idService.findExampleId());
+        chain.doFilter(request, response);
+    }
+}

src/main/java/com/wilkins/showcase/service/Example.java

@@ -0,0 +1,10 @@
+package com.wilkins.showcase.service;
+
+import java.util.List;
+
+public record Example (
+    String key,
+    String value,
+    String id,
+    List<String> parts) {
+}

src/main/java/com/wilkins/showcase/service/ExampleService.java

@@ -0,0 +1,6 @@
+package com.wilkins.showcase.service;
+
+public interface ExampleService {
+    String findExampleId();
+    Example createExample();
+}

src/main/java/com/wilkins/showcase/service/GreatExampleService.java

@@ -0,0 +1,36 @@
+package com.wilkins.showcase.service;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Component;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+import java.util.function.Supplier;
+
+@Service
+public class GreatExampleService implements ExampleService {
+
+    private final String prefix;
+    private final Supplier<String> supplier;
+    private final String joiner;
+
+    public GreatExampleService(@Value("${showcase.id-service.prefix}") String prefix,
+                               Supplier<String> supplier,
+                               @Value("${showcase.id-service.joiner}") String joiner) {
+        this.prefix = prefix;
+        this.supplier = supplier;
+        this.joiner = joiner;
+    }
+
+    @Override
+    public String findExampleId() {
+        return prefix + joiner + supplier.get();
+    }
+
+    @Override
+    public Example createExample() {
+        var exampleId = findExampleId();
+        var suppliedExample = supplier.get();
+        return new Example(prefix, suppliedExample, exampleId, List.of(prefix, suppliedExample, exampleId));
+    }
+}

src/main/resources/application.yaml

@@ -0,0 +1,4 @@
+showcase:
+  id-service:
+    prefix: "showcase"
+    joiner: "::"

src/test/groovy/com/wilkins/showcase/controllers/GreetingControllerSpec.groovy

@@ -0,0 +1,43 @@
+package com.wilkins.showcase.controllers
+
+import com.wilkins.showcase.service.ExampleService
+import org.spockframework.spring.SpringBean
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.boot.test.context.SpringBootTest
+import org.springframework.boot.test.web.client.TestRestTemplate
+import spock.lang.Specification
+import spock.lang.Unroll
+
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+class GreetingControllerSpec extends Specification {
+
+    @Autowired
+    TestRestTemplate restTemplate;
+
+    @SpringBean
+    ExampleService exampleService = Mock()
+
+    @Unroll
+    def "should wish #providedName an appropriate greeting"() {
+        given:
+        exampleService.findExampleId() >> "mock-id"
+
+        when:
+        def response= restTemplate
+                .getForEntity("/greeting?name={name}&salutation={salutation}", Greeting.class, providedName, providedSalutation)
+
+        then:
+        response.statusCode.value() == 200
+        response.headers.getFirst('x-trace-id') == 'mock-id'
+        with(response.body) {
+            salutation == providedSalutation
+            name == providedName
+        }
+
+        where:
+        providedName | providedSalutation
+        'world'      | 'hello'
+        'robin'      | "good afternoon"
+    }
+
+}

src/test/groovy/com/wilkins/showcase/service/GreatExampleServiceSpec.groovy

@@ -0,0 +1,50 @@
+package com.wilkins.showcase.service
+
+import spock.lang.Specification
+import spock.lang.Unroll
+
+import java.util.function.Supplier
+
+class GreatExampleServiceSpec extends Specification {
+
+    Supplier<String> stringSupplier = Mock()
+
+    @Unroll
+    def "ID String is generated correctly when using the GreatExampleService"() {
+        given:
+        stringSupplier.get() >> suppliedString
+        def idService = new GreatExampleService(something, stringSupplier, joiner)
+
+        expect:
+        expectedId == idService.findExampleId()
+
+        where:
+        something | suppliedString | joiner || expectedId
+        "abc"     | "123"          | "::"   || "abc::123"
+        "1"       | "2"            | "||"   || "1||2"
+    }
+
+    @Unroll
+    def "Example is generated correctly when using the key: #prefix and suppliedString: #suppliedString"() {
+        given:
+        stringSupplier.get() >> suppliedString
+        def exampleService = new GreatExampleService(prefix, stringSupplier, joiner)
+
+        when:
+        def example = exampleService.createExample()
+
+        then:
+        with(example) {
+            key == prefix
+            value == suppliedString
+            id == expectedId
+            parts == [prefix, suppliedString, expectedId] as List
+        }
+
+        where:
+        prefix | suppliedString | joiner || expectedId
+        "abc"  | "123"          | "::"   || "abc::123"
+        "1"    | "2"            | "//"   || "1//2"
+
+    }
+}