Update docs and samples on "slice" tests

See gh-75

samples/webflux-websocket/src/test/java/io/spring/sample/graphql/QueryTests.java

@@ -20,8 +20,7 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.context.annotation.ComponentScan;
-import org.springframework.context.annotation.FilterType;
+import org.springframework.context.annotation.Import;
 import org.springframework.graphql.GraphQlService;
 import org.springframework.graphql.boot.test.GraphQlTest;
 import org.springframework.graphql.test.tester.GraphQlTester;
@@ -29,10 +28,8 @@ import org.springframework.graphql.test.tester.GraphQlTester;
 /**
  * GraphQL query tests directly via {@link GraphQL}.
  */
-@GraphQlTest(controllers = SampleController.class,
-		includeFilters = @ComponentScan.Filter(
-				type = FilterType.ASSIGNABLE_TYPE,
-				classes = {ContextWebFilter.class, DataRepository.class}))
+@GraphQlTest(SampleController.class)
+@Import(TestConfig.class)
 public class QueryTests {
 
 	private GraphQlTester graphQlTester;

samples/webflux-websocket/src/test/java/io/spring/sample/graphql/SubscriptionTests.java

@@ -22,8 +22,7 @@ import reactor.core.publisher.Flux;
 import reactor.test.StepVerifier;
 
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.context.annotation.ComponentScan;
-import org.springframework.context.annotation.FilterType;
+import org.springframework.context.annotation.Import;
 import org.springframework.graphql.GraphQlService;
 import org.springframework.graphql.boot.test.GraphQlTest;
 import org.springframework.graphql.test.tester.GraphQlTester;
@@ -31,10 +30,8 @@ import org.springframework.graphql.test.tester.GraphQlTester;
 /**
  * GraphQL subscription tests directly via {@link GraphQL}.
  */
-@GraphQlTest(controllers = SampleController.class,
-		includeFilters = @ComponentScan.Filter(
-				type = FilterType.ASSIGNABLE_TYPE,
-				classes = {ContextWebFilter.class, DataRepository.class}))
+@GraphQlTest(SampleController.class)
+@Import(TestConfig.class)
 public class SubscriptionTests {
 
 	private GraphQlTester graphQlTester;

samples/webflux-websocket/src/test/java/io/spring/sample/graphql/TestConfig.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2002-2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.spring.sample.graphql;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * Collaborator and additional components for {@link SampleController} slice tests.
+ */
+@Configuration
+class TestConfig {
+
+	@Bean
+	public ContextWebFilter contextWebFilter() {
+		return new ContextWebFilter();
+	}
+
+	@Bean
+	public DataRepository dataRepository() {
+		return new DataRepository();
+	}
+
+}

spring-graphql-docs/src/docs/asciidoc/boot-starter.adoc

@@ -440,25 +440,44 @@ repositories {
 The following sections cover a range of options for testing a Spring GraphQL application.
 
 [[boot-graphql-testing-graphqltest]]
-=== Standalone GraphQL Server Tests
+=== GraphQL Slice Tests
 
-Use `@GraphQlTest` to test Spring GraphQL data `@Controller` and related GraphQL components
-without involving a Web transport or a Web framework (Spring MVC or WebFlux).
-`@GraphQlTest` auto-configures Spring GraphQL infrastructure and limits scanned beans to
-`@Controller`, `RuntimeWiringConfigurer`, `JsonComponent`, `WebInterceptor`, `Converter`,
-and `GenericConverter`, but excludes regular `@Component` and `@ConfigurationProperties`
-beans. To include `@ConfigurationProperties` beans, use `@EnableConfigurationProperties`.
+Use `@GraphQlTest` on a test class to create GraphQL tests focused on GraphQL request
+execution, without involving a Web layer, and loading only a subset of the application
+configuration.
+
+By default, `@GraphQlTest` limits scanning to the following beans:
+
+- `@Controller`
+- `RuntimeWiringConfigurer`
+- `JsonComponent`
+- `Converter`
+- `GenericConverter`
+
+Use the `controllers` attribute of `@GraphQlTest` to specify a controller class, or to
+list all data controllers required to perform requests in a test class. Leaving it empty,
+includes all controllers.
+
+To add collaborator and/or other components to a test class, use one of the following:
+
+- `@MockBean` fields in the test class.
+- `@Import` an `@Configuration` class into the test class.
+- Create a `@TestConfiguration` nested class.
+- Broaden the component scan via `includeFilters` on `@GraphQlTest`.
+
+To add properties, use the `properties` attribute of `@GraphQlTest`, or add
+`@EnableConfigurationProperties` on the test class.
 
 [NOTE]
 ====
-The arrangement is similar to the
-{spring-boot-ref-docs}/features.html#features.testing.spring-boot-applications.spring-mvc-tests[@WevMvcTest support],
-except there is no web framework in use, and `GraphQlService` is used to perform requests.
+`@GraphQlTest` is comparable to
+{spring-boot-ref-docs}/features.html#features.testing.spring-boot-applications.spring-mvc-tests[@WevMvcTest],
+which also uses test "slices" to create focused Web controller tests.
 ====
 
 [source,java,indent=0,subs="verbatim,quotes"]
 ----
-@GraphQlTest(controllers = BookController.class)
+@GraphQlTest(BookController.class)
 public class BookControllerTests {
 
 	@Autowired
@@ -478,11 +497,11 @@ public class BookControllerTests {
 }
 ----
 
-This mode is useful to test subscriptions without a WebSocket transport.
+This mode is useful to test subscriptions without WebSocket.
 
 [source,java,indent=0,subs="verbatim,quotes"]
 ----
-@GraphQlTest(controllers = GreetingController.class)
+@GraphQlTest(GreetingController.class)
 public class GreetingControllerTests {
 
 	@Autowired
@@ -505,20 +524,9 @@ public class GreetingControllerTests {
 }
 ----
 
-`GraphQlService` is used to perform the above test. It represents common infrastructure
-for HTTP and WebSocket transports that both Spring WebMvc and WebFlux handlers delegate to.
-Therefore, it does not involve a web framework and does not apply the `WebInterceptor`
-chain  before and after the call to the GraphQL Java engine,  which returns a Reactive
-Streams `Publisher`.
+`GraphQlService` performS the above request by calling directly the GraphQL Java engine,
+which returns a Reactive Streams `Publisher`.
 
-[NOTE]
-.Testing multiple controllers with `@GraphQlTest`
-====
-Because GraphQL is not about REST endpoints but navigating relations in an object graph,
-multiple `@Controller` components can be involved in a single query.
-For this case, the `@GraphQlTest` annotation supports testing multiple controllers through
-its `controllers` attribute.
-====
 
 [[boot-graphql-testing-mock]]
 === Client and Mock Server Tests

spring-graphql-docs/src/docs/asciidoc/testing.adoc

@@ -1,9 +1,9 @@
 [[testing]]
 = Testing
 
-You can test GraphQL requests using Spring's `WebTestClient`, just send and receive
-JSON, but a number of GraphQL specific details make this approach more cumbersome than it
-should be.
+It's possible to test GraphQL requests with Spring's `WebTestClient`, just sending and
+receiving JSON, but a number of GraphQL specific details make this approach more
+cumbersome than is necessary.
 
 
 
@@ -12,7 +12,6 @@ should be.
 
 `GraphQlTester` defines a workflow to test GraphQL requests with the following benefits:
 
-- Verify GraphQL responses are 200 (OK).
 - Verify no unexpected errors under the "errors" key in the response.
 - Decode under the "data" key in the response.
 - Use JsonPath to decode different parts of the response.
@@ -38,7 +37,10 @@ To create `GraphQlTester`, you only need a `GraphQlService`, and no transport:
 == `WebGraphQlTester`
 
 `WebGraphQlTester` extends `GraphQlTester` to add a workflow and configuration specific
-to <<index#web-transports>>. You need one of the following inputs to create it:
+to <<index#web-transports>>, and it always verifies GraphQL HTTP responses are 200 (OK).
+
+
+To create `WebGraphQlTester`, you need one of the following inputs:
 
 - `WebTestClient` -- perform requests as an HTTP client, either against <<index#web-http>>
 handlers without a server, or against a live server.
@@ -61,7 +63,7 @@ For Spring WebFlux without a server, you can point to your Spring configuration:
 	WebGraphQlTester tester = WebGraphQlTester.builder(client).build();
 ----
 
-For Spring MVC without a server, use the `MockMvcWebTestClient` builder:
+For Spring MVC without a server, the same but using `MockMvcWebTestClient`:
 
 [source,java,indent=0,subs="verbatim,quotes"]
 ----
@@ -76,7 +78,7 @@ For Spring MVC without a server, use the `MockMvcWebTestClient` builder:
 	WebGraphQlTester tester = WebGraphQlTester.builder(client).build();
 ----
 
-For tests against a live, running server:
+To test against a live, running server:
 
 [source,java,indent=0,subs="verbatim,quotes"]
 ----