diff -r ed48023d1d85 -r 3485327d3080 vmtest/src/main/java/org/apidesign/bck2brwsr/vmtest/VMTest.java
--- a/vmtest/src/main/java/org/apidesign/bck2brwsr/vmtest/VMTest.java	Sun Dec 23 17:02:34 2012 +0100
+++ b/vmtest/src/main/java/org/apidesign/bck2brwsr/vmtest/VMTest.java	Sun Dec 23 23:30:06 2012 +0100
@@ -17,20 +17,8 @@
  */
 package org.apidesign.bck2brwsr.vmtest;
 
-import java.io.File;
-import java.io.FileWriter;
-import java.io.IOException;
-import java.lang.reflect.Method;
-import java.util.Map;
-import java.util.WeakHashMap;
-import java.util.logging.Level;
-import java.util.logging.Logger;
-import javax.script.Invocable;
-import org.apidesign.bck2brwsr.launcher.MethodInvocation;
-import org.testng.Assert;
-import org.testng.ITest;
+import org.apidesign.bck2brwsr.vmtest.impl.CompareCase;
 import org.testng.annotations.Factory;
-import org.testng.annotations.Test;
 
 /** A TestNG {@link Factory} that seeks for {@link Compare} annotations
  * in provided class and builds set of tests that compare the computations
@@ -41,19 +29,7 @@
  *
  * @author Jaroslav Tulach <jtulach@netbeans.org>
  */
-public final class VMTest implements ITest {
-    private static final Launcher JS = new Launcher("js");
-    private static final Launcher BROWSER = new Launcher();
-    
-    private final Run first, second;
-    private final Method m;
-    
-    private VMTest(Method m, Run first, Run second) {
-        this.first = first;
-        this.second = second;
-        this.m = m;
-    }
-
+public final class VMTest {
     /** Inspects <code>clazz</code> and for each {@lik Compare} method creates
      * instances of tests. Each instance runs the test in different virtual
      * machine and at the end they compare the results.
@@ -62,164 +38,6 @@
      * @return the set of created tests
      */
     public static Object[] create(Class<?> clazz) {
-        Method[] arr = clazz.getMethods();
-        Object[] ret = new Object[5 * arr.length];
-        int cnt = 0;
-        for (Method m : arr) {
-            Compare c = m.getAnnotation(Compare.class);
-            if (c == null) {
-                continue;
-            }
-            final Run real = new Run(m, 0);
-            final Run js = new Run(m, 1);
-            final Run brwsr = new Run(m, 2);
-            ret[cnt++] = real;
-            ret[cnt++] = js;
-            ret[cnt++] = brwsr;
-            ret[cnt++] = new VMTest(m, real, js);
-            ret[cnt++] = new VMTest(m, real, brwsr);
-        }
-        Object[] r = new Object[cnt];
-        for (int i = 0; i < cnt; i++) {
-            r[i] = ret[i];
-        }
-        return r;
-    }
-
-    /** Test that compares the previous results.
-     * @throws Throwable 
-     */
-    @Test(dependsOnGroups = "run") public void compareResults() throws Throwable {
-        Object v1 = first.value;
-        Object v2 = second.value;
-        if (v1 != null) {
-            v1 = v1.toString();
-        } else {
-            v1 = "null";
-        }
-        Assert.assertEquals(v2, v1, "Comparing results");
-    }
-    
-    /** Test name.
-     * @return name of the tested method followed by a suffix
-     */
-    @Override
-    public String getTestName() {
-        return m.getName() + "[Compare " + second.typeName() + "]";
-    }
-
-    public static final class Run implements ITest {
-        private final Method m;
-        private final int type;
-        Object value;
-        private Invocable code;
-        private CharSequence codeSeq;
-        private static final Map<Class,Object[]> compiled = new WeakHashMap<>();
-        private Object inst;
-
-        private Run(Method m, int type) {
-            this.m = m;
-            this.type = type;
-            try {
-                initialize();
-            } catch (Throwable ex) {
-                Logger.getLogger(VMTest.class.getName()).log(Level.SEVERE, null, ex);
-            }
-        }
-
-        private void initialize() throws Throwable {
-            if (type == 1) {
-                inst = JS.addMethod(m.getDeclaringClass(), m.getName());
-            }
-            if (type == 2) {
-                inst = BROWSER.addMethod(m.getDeclaringClass(), m.getName());
-            }
-        }
-
-        @Test(groups = "run") public void executeCode() throws Throwable {
-            if (type == 1) {
-                MethodInvocation c = (MethodInvocation) inst;
-                JS.exec();
-                value = c.toString();
-            } else if (type == 2) {
-                MethodInvocation c = (MethodInvocation) inst;
-                BROWSER.exec();
-                value = c.toString();
-            } else {
-                value = m.invoke(m.getDeclaringClass().newInstance());
-            }
-        }
-        @Override
-        public String getTestName() {
-            return m.getName() + "[" + typeName() + "]";
-        }
-        
-        final String typeName() {
-            switch (type) {
-                case 0: return "Java";
-                case 1: return "JavaScript";
-                case 2: return "Browser";
-                default: return "Unknown type " + type;
-            }
-        }
-        
-        private static String computeSignature(Method m) {
-            StringBuilder sb = new StringBuilder();
-            appendType(sb, m.getReturnType());
-            for (Class<?> c : m.getParameterTypes()) {
-                appendType(sb, c);
-            }
-            return sb.toString();
-        }
-        
-        private static void appendType(StringBuilder sb, Class<?> t) {
-            if (t == null) {
-                sb.append('V');
-                return;
-            }
-            if (t.isPrimitive()) {
-                int ch = -1;
-                if (t == int.class) {
-                    ch = 'I';
-                }
-                if (t == short.class) {
-                    ch = 'S';
-                }
-                if (t == byte.class) {
-                    ch = 'B';
-                }
-                if (t == boolean.class) {
-                    ch = 'Z';
-                }
-                if (t == long.class) {
-                    ch = 'J';
-                }
-                if (t == float.class) {
-                    ch = 'F';
-                }
-                if (t == double.class) {
-                    ch = 'D';
-                }
-                assert ch != -1 : "Unknown primitive type " + t;
-                sb.append((char)ch);
-                return;
-            }
-            if (t.isArray()) {
-                sb.append("_3");
-                appendType(sb, t.getComponentType());
-                return;
-            }
-            sb.append('L');
-            sb.append(t.getName().replace('.', '_'));
-            sb.append("_2");
-        }
-    }
-    
-    static StringBuilder dumpJS(CharSequence sb) throws IOException {
-        File f = File.createTempFile("execution", ".js");
-        try (FileWriter w = new FileWriter(f)) {
-            w.append(sb);
-        }
-        return new StringBuilder(f.getPath());
+        return CompareCase.create(clazz);
     }
 }