added reproduction testcase for #25

Author: erosb

core/pom.xml

@@ -63,11 +63,11 @@
         <configuration>
           <instructions>
             <Bundle-SymbolicName>${project.artifactId}</Bundle-SymbolicName>
-            <Import-Package> * 
+            <Import-Package> *
             </Import-Package>
             <Export-Package>
               ${project.artifactId};version=${project.version},
-              ${project.artifactId}.loader;version=${project.version} 
+              ${project.artifactId}.loader;version=${project.version}
             </Export-Package>
           </instructions>
         </configuration>

tests/src/test/java/org/everit/json/schema/IssueTest.java

@@ -133,7 +133,11 @@ private void validate(final File file, final Schema schema, final boolean should
       throw new UncheckedIOException(e);
     }
     if (shouldBeValid && thrown != null) {
-      Assert.fail("validation failed with: " + thrown);
+      StringBuilder failureBuilder = new StringBuilder("validation failed with: " + thrown);
+      for (ValidationException e : thrown.getCausingExceptions()) {
+        failureBuilder.append("\n\t").append(e.getMessage());
+      }
+      Assert.fail(failureBuilder.toString());
     }
     if (!shouldBeValid && thrown == null) {
       Assert.fail("did not throw ValidationException for invalid subject");