Avoid using JVM’s default charset for String to byte[] in unit tests

spring-restdocs-core/src/test/java/org/springframework/restdocs/http/HttpRequestSnippetTests.java

@@ -98,7 +98,7 @@ public class HttpRequestSnippetTests {
 				"post-request-with-charset", this.snippet.getOutputDirectory())
 				.request("http://localhost/foo").method("POST")
 				.header("Content-Type", "text/plain;charset=UTF-8")
-				.content(japaneseContent).build());
+				.content(japaneseContent.getBytes("UTF-8")).build());
 	}
 
 	@Test

spring-restdocs-core/src/test/java/org/springframework/restdocs/http/HttpResponseSnippetTests.java

@@ -93,7 +93,7 @@ public class HttpResponseSnippetTests {
 		new HttpResponseSnippet().document(new OperationBuilder("response-with-charset",
 				this.snippet.getOutputDirectory()).response()
 				.header("Content-Type", "text/plain;charset=UTF-8")
-				.content(japaneseContent).build());
+				.content(japaneseContent.getBytes("UTF-8")).build());
 	}
 
 	@Test

spring-restdocs-core/src/test/java/org/springframework/restdocs/test/OperationBuilder.java

@@ -140,6 +140,11 @@ public class OperationBuilder {
 			return this;
 		}
 
+		public OperationRequestBuilder content(byte[] content) {
+			this.content = content;
+			return this;
+		}
+
 		public OperationRequestBuilder param(String name, String... values) {
 			for (String value : values) {
 				this.parameters.add(name, value);