Sample improvements (#47)

* Use @AutoConfigureHttpGraphQlTester

* Polishing in controllers

There is no need to specify type name and field if those match the
source object type name and the method name respectively.

* Use ClassNameTypeResolver

We can use the built-in TypeResolver that matches class names to schema
type names. The resolver behavior can be customized further if needed.
See ClassNameTypeResolver javadoc for details.

Author: rstoyanchev

products-subgraph/src/main/java/com/example/products/ProductsController.java

@@ -6,7 +6,6 @@
 import org.springframework.stereotype.Controller;
 
 import java.util.List;
-import java.util.Locale;
 import java.util.Map;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;

products-subgraph/src/test/java/com/example/products/ProductsApplicationTest.java

@@ -2,26 +2,21 @@
 
 import com.example.products.model.Product;
 import org.junit.jupiter.api.Test;
+
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.boot.test.autoconfigure.web.reactive.AutoConfigureWebTestClient;
+import org.springframework.boot.test.autoconfigure.graphql.tester.AutoConfigureHttpGraphQlTester;
 import org.springframework.boot.test.context.SpringBootTest;
-import org.springframework.boot.test.web.server.LocalServerPort;
 import org.springframework.graphql.test.tester.HttpGraphQlTester;
-import org.springframework.test.web.reactive.server.WebTestClient;
 
+@AutoConfigureHttpGraphQlTester
 @SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
 public class ProductsApplicationTest {
 
-  @LocalServerPort
-  int serverPort;
+  @Autowired
+  private HttpGraphQlTester tester;
 
   @Test
   public void verifiesProductQuery() {
-    WebTestClient testClient = WebTestClient.bindToServer()
-      .baseUrl("http://localhost:" + serverPort + "/graphql")
-      .build();
-    HttpGraphQlTester tester = HttpGraphQlTester.create(testClient);
-
     String query = """
       query ProductById($productId: ID!) {
         product(id: $productId) {

reviews-subgraph/src/main/java/com/example/reviews/GraphQLConfiguration.java

@@ -1,17 +1,18 @@
 package com.example.reviews;
 
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
 import com.apollographql.federation.graphqljava.Federation;
 import com.apollographql.federation.graphqljava._Entity;
 import com.example.reviews.model.Product;
 import graphql.schema.DataFetcher;
-import graphql.schema.TypeResolver;
+
 import org.springframework.boot.autoconfigure.graphql.GraphQlSourceBuilderCustomizer;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
-
-import java.util.List;
-import java.util.Map;
-import java.util.stream.Collectors;
+import org.springframework.graphql.execution.ClassNameTypeResolver;
 
 import static com.example.reviews.model.Product.PRODUCT_TYPE;
 
@@ -20,7 +21,7 @@ public class GraphQLConfiguration {
 
   @Bean
   public GraphQlSourceBuilderCustomizer federationTransform() {
-    DataFetcher entityDataFetcher = env -> {
+    DataFetcher<?> entityDataFetcher = env -> {
       List<Map<String, Object>> representations = env.getArgument(_Entity.argumentName);
       return representations.stream()
         .map(representation -> {
@@ -31,22 +32,13 @@ public GraphQlSourceBuilderCustomizer federationTransform() {
         })
         .collect(Collectors.toList());
     };
-    TypeResolver entityTypeResolver = env -> {
-      final Object src = env.getObject();
-      if (src instanceof Product) {
-        return env.getSchema()
-          .getObjectType(PRODUCT_TYPE);
-      }
-      return null;
-    };
 
-    return builder -> {
+    return builder ->
       builder.schemaFactory((registry, wiring)->
         Federation.transform(registry, wiring)
           .fetchEntities(entityDataFetcher)
-          .resolveEntityType(entityTypeResolver)
+          .resolveEntityType(new ClassNameTypeResolver())
           .build()
       );
-    };
   }
 }

reviews-subgraph/src/main/java/com/example/reviews/ReviewsController.java

@@ -19,7 +19,7 @@ public class ReviewsController {
     "5", List.of(new Review("1050", "Amazing! Would Fly Again!", 5), new Review("1051", 5))
   );
 
-  @SchemaMapping(typeName="Product", field="reviews")
+  @SchemaMapping
   public List<Review> reviews(Product show) {
     return REVIEWS.getOrDefault(show.id(), Collections.emptyList());
   }

reviews-subgraph/src/test/java/com/example/reviews/ReviewsApplicationTest.java

@@ -4,24 +4,20 @@
 import java.util.List;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.graphql.tester.AutoConfigureHttpGraphQlTester;
 import org.springframework.boot.test.context.SpringBootTest;
-import org.springframework.boot.test.web.server.LocalServerPort;
 import org.springframework.graphql.test.tester.HttpGraphQlTester;
-import org.springframework.test.web.reactive.server.WebTestClient;
 
+@AutoConfigureHttpGraphQlTester
 @SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
 public class ReviewsApplicationTest {
 
-  @LocalServerPort
-  int serverPort;
+  @Autowired
+  private HttpGraphQlTester tester;
 
   @Test
   public void verifiesProductQuery() {
-    WebTestClient testClient = WebTestClient.bindToServer()
-      .baseUrl("http://localhost:" + serverPort + "/graphql")
-      .build();
-    HttpGraphQlTester tester = HttpGraphQlTester.create(testClient);
-
     String query = """
       query Entities($representations: [_Any!]!) {
         _entities(representations: $representations) {