Polishing.

Add missing line breaks after XML declaration and before the file end.

See #218

src/test/java/org/springframework/data/release/build/MavenBuildSystemUnitTests.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright 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.data.release.build;
+
+import static org.assertj.core.api.Assertions.*;
+
+import java.io.InputStream;
+
+import org.apache.commons.io.IOUtils;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.core.io.ClassPathResource;
+
+import org.xmlbeam.XBProjector;
+
+/**
+ * Unit tests for {@link MavenBuildSystem}.
+ *
+ * @author Mark Paluch
+ */
+class MavenBuildSystemUnitTests {
+
+	XBProjector projector = new BuildConfiguration().projectionFactory();
+
+	@Test
+	void shouldAddLineBreaksAfterProcessing() throws Exception {
+
+		ClassPathResource resource = new ClassPathResource("sample-pom.xml");
+
+		try (InputStream is = resource.getInputStream()) {
+
+			byte[] bytes = MavenBuildSystem.doWithProjection(projector, is, Pom.class, pom -> {});
+
+			assertThat(new String(bytes)).contains("<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>"
+					+ IOUtils.LINE_SEPARATOR + "<project xmlns=\"http://maven.apache.org/POM/4.0.0\" ")
+					.endsWith(IOUtils.LINE_SEPARATOR);
+		}
+	}
+}