Added extension method for writing XML to a String

Author: magneticflux-

src/test/groovy/com/github/magneticflux/rss/namespaces/standard/elements/CategoryTest.groovy

@@ -1,7 +1,6 @@
 package com.github.magneticflux.rss.namespaces.standard.elements
 
 import com.github.magneticflux.rss.PersisterSpecification
-import org.codehaus.groovy.runtime.StringBufferWriter
 import spock.lang.Unroll
 
 class CategoryTest extends PersisterSpecification {
@@ -10,11 +9,10 @@ class CategoryTest extends PersisterSpecification {
 	def 'category  #object read/write'() {
 
 		when: 'the object is written to XML'
-		def output = new StringBuffer()
-		persister.write(object, new StringBufferWriter(output))
+		def output = persister.write(object)
 
 		then: 'the output XML equals the given XML'
-		output.toString() == xml
+		output == xml
 
 		when: 'the XML is read to an object'
 		def input = persister.read(Category, xml)

src/test/groovy/com/github/magneticflux/rss/namespaces/standard/elements/CloudTest.groovy

@@ -1,19 +1,17 @@
 package com.github.magneticflux.rss.namespaces.standard.elements
 
 import com.github.magneticflux.rss.PersisterSpecification
-import org.codehaus.groovy.runtime.StringBufferWriter
 import spock.lang.Unroll
 
 class CloudTest extends PersisterSpecification {
 	@Unroll
 	def 'cloud #object read/write'() {
 
 		when: 'the object is written to XML'
-		def output = new StringBuffer()
-		persister.write(object, new StringBufferWriter(output))
+		def output = persister.write(object)
 
 		then: 'the output XML equals the given XML'
-		output.toString() == xml
+		output == xml
 
 		when: 'the XML is read to an object'
 		def input = persister.read(Cloud, xml)

src/test/groovy/com/github/magneticflux/rss/namespaces/standard/elements/EnclosureTest.groovy

@@ -1,19 +1,17 @@
 package com.github.magneticflux.rss.namespaces.standard.elements
 
 import com.github.magneticflux.rss.PersisterSpecification
-import org.codehaus.groovy.runtime.StringBufferWriter
 import spock.lang.Unroll
 
 class EnclosureTest extends PersisterSpecification {
 	@Unroll
 	def 'enclosure #object read/write'() {
 
 		when: 'the object is written to XML'
-		def output = new StringBuffer()
-		persister.write(object, new StringBufferWriter(output))
+		def output = persister.write(object)
 
 		then: 'the output XML equals the given XML'
-		output.toString() == xml
+		output == xml
 
 		when: 'the XML is read to an object'
 		def input = persister.read(Enclosure, xml)

src/test/kotlin/com/github/magneticflux/rss/PersisterUtils.kt

@@ -0,0 +1,17 @@
+package com.github.magneticflux.rss
+
+import org.codehaus.groovy.runtime.StringBufferWriter
+import org.simpleframework.xml.core.Persister
+
+/**
+ * This extension function helps getting XML data from a persister as a String.
+ *
+ * @param any the object to write
+ * @return a String containing the written XML
+ * @receiver the persister with which to write the XML
+ */
+fun Persister.write(any: Any): String {
+    val buffer = StringBuffer()
+    this.write(any, StringBufferWriter(buffer))
+    return buffer.toString()
+}

src/test/resources/META-INF/services/org.codehaus.groovy.runtime.ExtensionModule

@@ -0,0 +1,3 @@
+moduleName=persister-module
+moduleVersion=1.0
+extensionClasses=com.github.magneticflux.rss.PersisterUtilsKt