Update WordProblemSolverTest.java

exercises/wordy/src/test/java/WordProblemSolverTest.java

@@ -6,7 +6,7 @@ import org.junit.rules.ExpectedException;
 
 import static org.junit.Assert.assertEquals;
 
-class WordProblemSolverTest {
+public class WordProblemSolverTest {
 
     /*
      * See https://github.com/junit-team/junit4/wiki/Rules for information on JUnit Rules in general and