[GDC-161] openapi doc strings with literal block style (#915)

example/example-openapi/src/main/resources/config/openapi.yaml

@@ -3,6 +3,10 @@ openapi: 3.0.2
 info:
   title: Breweries
   version: 3.0.0
+  description: |
+    This is an API for brewery data.
+    It tells you all about breweries and their beers.
+    And much much more.
 
 paths:
   /noop:

service/openapi/src/main/java/org/dotwebstack/framework/service/openapi/handler/OpenApiRequestHandler.java

@@ -3,6 +3,7 @@
 import static org.dotwebstack.framework.core.helpers.ExceptionHelper.invalidConfigurationException;
 
 import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.fasterxml.jackson.dataformat.yaml.YAMLGenerator;
 import com.fasterxml.jackson.dataformat.yaml.YAMLMapper;
 import java.io.IOException;
 import java.io.InputStream;
@@ -21,7 +22,7 @@ public class OpenApiRequestHandler implements HandlerFunction<ServerResponse> {
 
   public OpenApiRequestHandler(InputStream openApiStream) {
     try {
-      var mapper = new YAMLMapper();
+      var mapper = new YAMLMapper().enable(YAMLGenerator.Feature.LITERAL_BLOCK_STYLE);
       ObjectNode specNode = VendorExtensionHelper.removeVendorExtensions(openApiStream, mapper);
       openApiSpec = mapper.writer()
           .writeValueAsString(specNode);

service/openapi/src/test/java/org/dotwebstack/framework/service/openapi/handler/OpenApiRequestHandlerTest.java

@@ -0,0 +1,79 @@
+package org.dotwebstack.framework.service.openapi.handler;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.hasItem;
+import static org.hamcrest.Matchers.is;
+
+import java.util.List;
+import lombok.NonNull;
+import org.dotwebstack.framework.service.openapi.TestResources;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.codec.HttpMessageWriter;
+import org.springframework.mock.http.server.reactive.MockServerHttpRequest;
+import org.springframework.mock.web.server.MockServerWebExchange;
+import org.springframework.web.reactive.function.server.HandlerStrategies;
+import org.springframework.web.reactive.function.server.ServerRequest;
+import org.springframework.web.reactive.function.server.ServerResponse;
+import org.springframework.web.reactive.result.view.ViewResolver;
+import reactor.test.StepVerifier;
+
+
+class OpenApiRequestHandlerTest {
+
+  private ServerResponse.Context context;
+
+  @BeforeEach
+  public void createContext() {
+    HandlerStrategies strategies = HandlerStrategies.withDefaults();
+    context = new ServerResponse.Context() {
+
+      @NonNull
+      @Override
+      public List<HttpMessageWriter<?>> messageWriters() {
+        return strategies.messageWriters();
+      }
+
+      @NonNull
+      @Override
+      public List<ViewResolver> viewResolvers() {
+        return strategies.viewResolvers();
+      }
+    };
+  }
+
+  @Test
+  void handle_returnsExpectedServerResponse_whenRequested() {
+    var serverHttpRequest = MockServerHttpRequest.method(HttpMethod.GET, "")
+        .build();
+    var exchange = MockServerWebExchange.from(serverHttpRequest);
+    var request = ServerRequest.create(exchange, List.of());
+
+    var responseMono = new OpenApiRequestHandler(TestResources.openApiStream()).handle(request)
+        .flatMap(serverResponse -> {
+          assertThat(serverResponse.statusCode(), is(HttpStatus.OK));
+          assertThat(serverResponse.headers()
+              .get("Content-type"), hasItem("text/yaml;charset=utf-8"));
+          return serverResponse.writeTo(exchange, context);
+        });
+
+    StepVerifier.create(responseMono)
+        .verifyComplete();
+
+    StepVerifier.create(exchange.getResponse()
+        .getBodyAsString())
+        .assertNext(body -> {
+          assertThat(body, containsString("openapi: \"3.0.2\""));
+          assertThat(body, containsString("""
+              description: |
+                  This is an API for brewery data.
+                  It tells you all about breweries and their beers.
+                  And much much more.
+              """));
+        })
+        .verifyComplete();
+  }
+}

service/openapi/src/test/resources/config/model/openapi.yml

@@ -3,6 +3,10 @@ openapi: 3.0.2
 info:
   title: test API
   version: 3.0.0
+  description: |
+    This is an API for brewery data.
+    It tells you all about breweries and their beers.
+    And much much more.
 
 components:
   schemas: