Test for lexing script with and without globals

LexerTest.java

import org.jcodings.Encoding;
import org.jruby.Ruby;
import org.jruby.common.NullWarnings;
import org.jruby.lexer.ByteListLexerSource;
import org.jruby.lexer.LexerSource;
import org.jruby.lexer.LexingCommon;
import org.jruby.lexer.yacc.RubyLexer;
import org.jruby.parser.ParserConfiguration;
import org.jruby.parser.ParserSupport;
import org.jruby.parser.RubyParserResult;
import org.jruby.util.ByteList;
import org.junit.Test;

import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;

public class LexerTest {

  private RubyLexer makeLexer(LexerSource lexerSource){
    ParserSupport parserSupport = new ParserSupport();
    RubyLexer lexer = new RubyLexer(parserSupport, lexerSource, new NullWarnings(Ruby.getGlobalRuntime()));
    parserSupport.setLexer(lexer);
    parserSupport.setConfiguration(new ParserConfiguration(Ruby.getGlobalRuntime(), 0, false, true, false));
    parserSupport.setResult(new RubyParserResult());
    parserSupport.setWarnings(new NullWarnings(Ruby.getGlobalRuntime()));
    parserSupport.initTopLocalVariables();

    lexer.setState(LexingCommon.EXPR_BEG);
    return lexer;
  }

  public void lexIt(String code, Encoding encoding, Charset charset) throws Exception {
    LexerSource lexerSource = new ByteListLexerSource("test", 0, new ByteList(code.getBytes(charset)), null);
    lexerSource.setEncoding(encoding);

    RubyLexer lexer = makeLexer(lexerSource);
    while (!lexer.eofp){
      lexer.nextToken();
    }

  }

  @Test
  public void test_UTF8_no_globals() throws Exception {
    lexIt("puts 'Hello World'", Encoding.load("UTF8"), StandardCharsets.UTF_8);
  }
  @Test
  public void test_UTF8_with_globals() throws Exception {
    lexIt("puts $PROGRAM_NAME", Encoding.load("UTF8"), StandardCharsets.UTF_8);
  }

  @Test
  public void test_UTF16LE_no_globals() throws Exception {
    lexIt("puts 'Hello World'", Encoding.load("UTF16LE"), StandardCharsets.UTF_16LE);
  }

  @Test
  public void test_UTF16LE_with_globals() throws Exception {
    lexIt("puts $PROGRAM_NAME", Encoding.load("UTF16LE"), StandardCharsets.UTF_16LE);
  }

  @Test
  public void test_UTF16BE_no_globals() throws Exception {
    lexIt("puts 'Hello World'", Encoding.load("UTF16BE"), StandardCharsets.UTF_16BE);
  }

  @Test
  public void test_UTF16BE_with_globals() throws Exception {
    lexIt("puts $PROGRAM_NAME", Encoding.load("UTF16BE"), StandardCharsets.UTF_16BE);
  }
  
}