// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
// 3. Neither the name of the copyright holders nor the names of its
//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// THE POSSIBILITY OF SUCH DAMAGE.
package org.objectweb.asm;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;

import org.junit.jupiter.api.Test;

/**
 * Label tests.
 *
 * @author Eric Bruneton
 */
public class LabelTest {

  /** Tests that {@link Label#toString()} returns strings starting with "L". */
  @Test
  public void testToString() {
    assertEquals('L', new Label().toString().charAt(0));
  }

  /** Tests that {@link Label#getOffset()} returns a correct offset after the label is visited. */
  @Test
  public void testGetOffset() {
    Label label = new Label();
    ClassWriter classWriter = new ClassWriter(0);
    MethodVisitor methodVisitor =
        classWriter.visitMethod(Opcodes.ACC_PUBLIC, "m", "()V", null, null);
    methodVisitor.visitCode();
    methodVisitor.visitVarInsn(Opcodes.ALOAD, 0);
    methodVisitor.visitLabel(label);
    assertEquals(1, label.getOffset());
  }

  /** Tests that {@link Label#getOffset()} throws an exception before the label is visited. */
  @Test
  public void testGetOffset_illegalState() {
    assertThrows(RuntimeException.class, () -> new Label().getOffset());
  }
}
