Refactoring in Client and Tester builder implementations

The default transport-specific client and tester extensions contained
their builder implementations, but it makes more sense the other way
around since the extensions are mainly about the builders they provide.

Author: rstoyanchev

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

@@ -198,7 +198,7 @@ request execution as any `GraphQlTester`.
 
 Many times it's enough to test GraphQL requests on the server side, without the use of a
 client to send requests over a transport protocol. To test directly against a
-`ExecutionGraphQlService`, use the `GraphQlServiceTester` extension:
+`ExecutionGraphQlService`, use the `ExecutionGraphQlServiceTester` extension:
 
 [source,java,indent=0,subs="verbatim,quotes"]
 ----

spring-graphql-test/src/main/java/org/springframework/graphql/test/tester/DefaultExecutionGraphQlServiceTesterBuilder.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2002-2022 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 org.springframework.graphql.test.tester;
+
+
+import java.util.function.Consumer;
+
+import org.springframework.graphql.ExecutionGraphQlService;
+import org.springframework.util.Assert;
+
+
+/**
+ * Default {@link ExecutionGraphQlServiceTester.Builder} implementation that
+ * wraps an {@code ExecutionGraphQlService}.
+ *
+ * @author Rossen Stoyanchev
+ * @since 1.0.0
+ */
+final class DefaultExecutionGraphQlServiceTesterBuilder
+		extends AbstractGraphQlTesterBuilder<DefaultExecutionGraphQlServiceTesterBuilder>
+		implements ExecutionGraphQlServiceTester.Builder<DefaultExecutionGraphQlServiceTesterBuilder> {
+
+	private final ExecutionGraphQlService service;
+
+
+	DefaultExecutionGraphQlServiceTesterBuilder(ExecutionGraphQlService service) {
+		Assert.notNull(service, "GraphQlService is required");
+		this.service = service;
+	}
+
+	DefaultExecutionGraphQlServiceTesterBuilder(GraphQlServiceGraphQlTransport transport) {
+		this.service = transport.getGraphQlService();
+	}
+
+
+	@Override
+	public ExecutionGraphQlServiceTester build() {
+		GraphQlServiceGraphQlTransport transport = new GraphQlServiceGraphQlTransport(this.service);
+		GraphQlTester tester = super.buildGraphQlTester(transport);
+		return new DefaultExecutionGraphQlServiceTester(tester, transport, getBuilderInitializer());
+	}
+
+
+	/**
+	 * Default {@link ExecutionGraphQlServiceTester} implementation.
+	 */
+	private static class DefaultExecutionGraphQlServiceTester
+			extends AbstractDelegatingGraphQlTester implements ExecutionGraphQlServiceTester {
+
+		private final GraphQlServiceGraphQlTransport transport;
+
+		private final Consumer<AbstractGraphQlTesterBuilder<?>> builderInitializer;
+
+		private DefaultExecutionGraphQlServiceTester(GraphQlTester tester, GraphQlServiceGraphQlTransport transport,
+				Consumer<AbstractGraphQlTesterBuilder<?>> builderInitializer) {
+
+			super(tester);
+
+			Assert.notNull(transport, "GraphQlServiceTransport is required");
+			Assert.notNull(builderInitializer, "`builderInitializer` is required");
+
+			this.transport = transport;
+			this.builderInitializer = builderInitializer;
+		}
+
+		@Override
+		public DefaultExecutionGraphQlServiceTesterBuilder mutate() {
+			DefaultExecutionGraphQlServiceTesterBuilder builder = new DefaultExecutionGraphQlServiceTesterBuilder(this.transport);
+			this.builderInitializer.accept(builder);
+			return builder;
+		}
+
+	}
+
+}