@Test
  public void test1() {
    Ruby ruby = Ruby.newInstance();
    IRubyObject hash = ruby.evalScriptlet("{ \"Jane Doe\" => 10, \"Jim Doe\" => 6 }");
    assertThat(hash, instanceOf(RubyHash.class));
    RubyHash rubyHash = (RubyHash) hash;
    // Should return previous value 10, but returns the new value 42
    assertThat(rubyHash.put("Jane Doe", 42), is((Object) 10)); 
  }

  @Test
  public void test2() {
    Ruby ruby = Ruby.newInstance();
    IRubyObject hash = ruby.evalScriptlet("{ \"Jane Doe\" => 10, \"Jim Doe\" => 6 }");
    assertThat(hash, instanceOf(RubyHash.class));
    RubyHash rubyHash = (RubyHash) hash;
    // Should return null because the key wasn't present before, but returns the new value 42
    assertThat(rubyHash.put("Robert Panzer", 42), nullValue());
  }