### Question:
Groups { public synchronized Group get( String name ) { if ( isGlobalGroup( name ) ) { return Group.GLOBAL; } Group group = byName.get( name ); if ( group == null ) { throw new HeaderException( "Group '" + name + "' not found. Available groups are: " + groupNames() ); } return group; }  synchronized Group getOrCreate( String name ); synchronized Group get( String name ); Group get( int id ); int size();  }### Answer:
@Test ( expected = HeaderException.class ) public void shouldFailOnGettingNonExistentGroup() { Groups groups = new Groups(); groups.get( "Something" ); }