assertFalse(
        Visibility.PUBLIC.isVisible(VisibilityMethods.class.getDeclaredMethod("privateMethod")));
    assertFalse(
        Visibility.PUBLIC.isVisible(
            VisibilityMethods.class.getDeclaredMethod("packagePrivateMethod")));
    assertFalse(
        Visibility.PUBLIC.isVisible(VisibilityMethods.class.getDeclaredMethod("protectedMethod")));
    assertTrue(

    PACKAGE {
      @Override
      boolean isVisible(int modifiers) {
        return !Modifier.isPrivate(modifiers);
      }
    },

    PROTECTED {
      @Override
      boolean isVisible(int modifiers) {
        return Modifier.isPublic(modifiers) || Modifier.isProtected(modifiers);
      }
    },

    PUBLIC {
      @Override
      boolean isVisible(int modifiers) {

    PACKAGE {
      @Override
      boolean isVisible(int modifiers) {
        return !Modifier.isPrivate(modifiers);
      }
    },

    PROTECTED {
      @Override
      boolean isVisible(int modifiers) {
        return Modifier.isPublic(modifiers) || Modifier.isProtected(modifiers);
      }
    },

    PUBLIC {
      @Override
      boolean isVisible(int modifiers) {

  private final ClassSanityTester tester = new ClassSanityTester();
  private Visibility visibility = Visibility.PACKAGE;
  private Predicate<Class<?>> classFilter =
      (Class<?> cls) -> visibility.isVisible(cls.getModifiers());

  /**
   * Restricts the sanity tests for public API only. By default, package-private API are also
   * covered.
   */
  protected final void publicApiOnly() {

  private final ClassSanityTester tester = new ClassSanityTester();
  private Visibility visibility = Visibility.PACKAGE;
  private Predicate<Class<?>> classFilter =
      (Class<?> cls) -> visibility.isVisible(cls.getModifiers());

  /**
   * Restricts the sanity tests for public API only. By default, package-private API are also
   * covered.
   */
  protected final void publicApiOnly() {

    }.also { expected ->
      assertThat(expected).hasMessage("expected at least 1 part")
    }
  }

  @Test fun `skip preamble`() {
    val multipart =
      """
      |this is the preamble! it is invisible to application code
      |
      |--simple boundary
      |
      |abcd
      |--simple boundary--
      """.trimMargin()
        .replace("\n", "\r\n")

    val parts =
      MultipartReader(