diff --git a/rest-api/src/test/java/lcsb/mapviewer/api/convert/ConvertRestImplTest.java b/rest-api/src/test/java/lcsb/mapviewer/api/convert/ConvertRestImplTest.java
index 5154d715356ebd0f9cb9e50f4615e7c63c8b78a9..2aaa6b4325874bd148881d3912835eee02b6d8bf 100644
--- a/rest-api/src/test/java/lcsb/mapviewer/api/convert/ConvertRestImplTest.java
+++ b/rest-api/src/test/java/lcsb/mapviewer/api/convert/ConvertRestImplTest.java
@@ -73,7 +73,7 @@ public class ConvertRestImplTest extends RestTestFunctions {
 
   @Test
   public void testCelDesigner2Sbml1() throws Exception {
-    String content = readFile("testFiles/convert/sample-cd.xml");
+    byte[] content = readFile("testFiles/convert/sample-cd.xml").getBytes();
     String result = convertRestImpl.convert(
         "lcsb.mapviewer.converter.model.celldesigner.CellDesignerXmlParser",
         "lcsb.mapviewer.converter.model.sbml.SbmlParser", content);
@@ -84,16 +84,16 @@ public class ConvertRestImplTest extends RestTestFunctions {
   @Test
   public void testCelDesigner2Svg() throws Exception {
     String content = readFile("testFiles/convert/sample-cd.xml");
-    String result = convertRestImpl.converToImage("CellDesigner_SBML", "svg", content).toString();
+    String result = convertRestImpl.converToImage("CellDesigner_SBML", "svg", content.getBytes()).toString();
 
     assertTrue(result.contains("<rect"));
   }
 
   @Test
   public void testCellDesigner2Sbml2Svg() throws Exception {
-    String content = readFile("testFiles/convert/neuron_cd.xml");
+    byte[] content = readFile("testFiles/convert/neuron_cd.xml").getBytes();
     String resultSbml = convertRestImpl.convert("CellDesigner_SBML", "SBML", content).toString();
-    String resultSvg = convertRestImpl.converToImage("SBML", "svg", resultSbml).toString();
+    String resultSvg = convertRestImpl.converToImage("SBML", "svg", resultSbml.getBytes()).toString();
 
     assertTrue(resultSvg.contains("<rect"));
   }
@@ -101,10 +101,10 @@ public class ConvertRestImplTest extends RestTestFunctions {
   @Test
   public void testCellDesigner2Sbml2CellDesignerSvg() throws Exception {
     String content = readFile("testFiles/convert/neuron_cd.xml");
-    String resultSbml = convertRestImpl.convert("CellDesigner_SBML", "SBML", content).toString();
-    String resultCellDesignerSbml = convertRestImpl.convert("SBML", "CellDesigner_SBML", resultSbml)
+    String resultSbml = convertRestImpl.convert("CellDesigner_SBML", "SBML", content.getBytes()).toString();
+    String resultCellDesignerSbml = convertRestImpl.convert("SBML", "CellDesigner_SBML", resultSbml.getBytes())
         .toString();
-    String resultSvg = convertRestImpl.converToImage("CellDesigner_SBML", "svg", resultCellDesignerSbml)
+    String resultSvg = convertRestImpl.converToImage("CellDesigner_SBML", "svg", resultCellDesignerSbml.getBytes())
         .toString();
 
     assertTrue(resultSvg.contains("<rect"));
@@ -113,8 +113,8 @@ public class ConvertRestImplTest extends RestTestFunctions {
   @Test
   public void testScaling() throws Exception {
     String content = readFile("testFiles/convert/sample-cd.xml");
-    String result1 = convertRestImpl.converToImage("CellDesigner_SBML", "svg", content, 50.0, 50.0).toString();
-    String result2 = convertRestImpl.converToImage("CellDesigner_SBML", "svg", content, 100.0, 100.0)
+    String result1 = convertRestImpl.converToImage("CellDesigner_SBML", "svg", content.getBytes(), 50.0, 50.0).toString();
+    String result2 = convertRestImpl.converToImage("CellDesigner_SBML", "svg", content.getBytes(), 100.0, 100.0)
         .toString();
 
     Pattern pattern = Pattern.compile(".*scale\\(([0-9]+\\.[0-9]+),([0-9]+\\.[0-9]+)\\).*");
@@ -131,8 +131,8 @@ public class ConvertRestImplTest extends RestTestFunctions {
   public void test1() throws Exception {
     String content = readFile("testFiles/convert/glycolysis2.xml");
 
-    String result = convertRestImpl.convert("CellDesigner_SBML", "SBML", content);
-    ByteArrayOutputStream result1 = convertRestImpl.converToImage("SBML", "svg", result);
+    String result = convertRestImpl.convert("CellDesigner_SBML", "SBML", content.getBytes());
+    ByteArrayOutputStream result1 = convertRestImpl.converToImage("SBML", "svg", result.getBytes());
 
     File output = new File("testFiles/convert/glycolysis2.svg");
 
@@ -147,8 +147,8 @@ public class ConvertRestImplTest extends RestTestFunctions {
   public void test2() throws Exception {
     String content = readFile("testFiles/convert/glycolysis2.xml");
 
-    String result = convertRestImpl.convert("CellDesigner_SBML", "SBML", content);
-    String result1 = convertRestImpl.convert("SBML", "CellDesigner_SBML", result);
+    String result = convertRestImpl.convert("CellDesigner_SBML", "SBML", content.getBytes());
+    String result1 = convertRestImpl.convert("SBML", "CellDesigner_SBML", result.getBytes());
 
     assertNotNull(result);
     assertNotNull(result1);
@@ -157,7 +157,7 @@ public class ConvertRestImplTest extends RestTestFunctions {
   @Test
   public void testCelDesigner2Sbgn() throws Exception {
     String content = readFile("testFiles/convert/sample-cd.xml");
-    String result = convertRestImpl.convert("CellDesigner_SBML", "SBGN-ML", content).toString();
+    String result = convertRestImpl.convert("CellDesigner_SBML", "SBGN-ML", content.getBytes()).toString();
     assertTrue(result.contains("glyph class=\"complex\""));
   }
 
@@ -181,14 +181,14 @@ public class ConvertRestImplTest extends RestTestFunctions {
 
     targets.addAll(extractIdsFromOutputs(info));
     for (String target : targets) {
-      String result = convertRestImpl.convert(converter, target, content).toString();
+      String result = convertRestImpl.convert(converter, target, content.getBytes()).toString();
       assertTrue(result.length() > 0);
     }
 
     targets.clear();
     targets.addAll(extractIdsFromOutputs(infoImage));
     for (String target : targets) {
-      String result = convertRestImpl.converToImage(converter, target, content).toString();
+      String result = convertRestImpl.converToImage(converter, target, content.getBytes()).toString();
       assertTrue(result.length() > 0);
     }
   }