doubt BDOO Failed JUnit.framework

Hello, I get the following error:

junit.framework.AssertionFailedError
    at TestGestors.provaIncrementarPreuDistribuidor1(TestGestors.java:189)

and this other one

junit.framework.AssertionFailedError
    at TestGestors.provaIncrementarPreu(TestGestors.java:183)

I do not know what it means or understand how to avoid it.

I put the code parts that give the Show Failed:

Line 189

 @Test
    public void provaIncrementarPreuDistribuidor1() throws GestorException{
        gestorArticleExtern.incrementarPreu(1, 70);
        assertTrue(comparaLlistesArticles(gestorArticle.obtenirArticles(),totsIncrementatsEl70pcDist1));
    }  



 public void incrementarPreu(int codiDistribuidor, float percentantge) {
        //TODO completar el metode

        Query q = em.createQuery("SELECT a FROM Article a");
          List<Article> articles = q.getResultList();
          for (Article a : articles) {
    a.setPreu(a.getPreu() * percentantge);
    em.merge(a);
}

    }

line 183

 public void provaIncrementarPreu() throws GestorException{
        gestorArticle.incrementarPreu(50);
        assertTrue(comparaLlistesArticles(gestorArticle.obtenirArticles(),totsIncrementatsEl50pc));
    } 

 public void incrementarPreu(float percentantge) {
        //TODO completar el metode
        Query ap = em.createNamedQuery("Article.aumentapreu");
        ap.setParameter("quantitat", percentantge);
        em.getTransaction().begin();
        ap.executeUpdate();
        em.getTransaction().commit();



    }

I'm missing something?