Add a test for the write to string function in GedWriter

Fixes #740

Compares the write to string result from a data set with reading
the existing file from disk.

gedbrowser-writer/src/test/java/org/schoellerfamily/gedbrowser/writer/test/GedWriterTest.java

@@ -1,10 +1,12 @@
 package org.schoellerfamily.gedbrowser.writer.test;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
 import java.io.File;
 import java.io.FilenameFilter;
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 
 import org.apache.commons.io.FileUtils;
 import org.apache.commons.logging.Log;
@@ -80,6 +82,17 @@ public void test() throws IOException {
         assertSuccess();
     }
 
+    /**
+     * @throws IOException if file IO fails
+     */
+    @Test
+    public void testString() throws IOException {
+        final GedWriter writer = new GedWriter(root);
+        final String writeString = writer.writeString();
+        final String readString = FileUtils.readFileToString(new File(inputFilename), StandardCharsets.UTF_8);
+        assertEquals("Input and output should match", readString, writeString);
+    }
+
     /**
      * @throws IOException if there are problems reading or writing files
      */