### Question:
PathUtils { public static void validatePath(String path, boolean isSequential) throws IllegalArgumentException { validatePath(isSequential ? path + "1" : path); }  static void validatePath(String path, boolean isSequential); static void validatePath(String path); static String normalizeFileSystemPath(String path);  }### Answer:
@Test public void testValidatePath_ValidPath() { PathUtils.validatePath("/this is / a valid/path"); }
@Test public void testValidatePath_Null() { assertThrows(IllegalArgumentException.class, () -> { PathUtils.validatePath(null); }); }
@Test public void testValidatePath_EmptyString() { assertThrows(IllegalArgumentException.class, () -> { PathUtils.validatePath(""); }); }
@Test public void testValidatePath_NotAbsolutePath() { assertThrows(IllegalArgumentException.class, () -> { PathUtils.validatePath("not/valid"); }); }
@Test public void testValidatePath_EndsWithSlash() { assertThrows(IllegalArgumentException.class, () -> { PathUtils.validatePath("/ends/with/slash/"); }); }
@Test public void testValidatePath_ContainsNullCharacter() { assertThrows(IllegalArgumentException.class, () -> { PathUtils.validatePath("/test\u0000"); }); }
@Test public void testValidatePath_DoubleSlash() { assertThrows(IllegalArgumentException.class, () -> { PathUtils.validatePath("/double }); }
@Test public void testValidatePath_SinglePeriod() { assertThrows(IllegalArgumentException.class, () -> { PathUtils.validatePath("/single/./period"); }); }
@Test public void testValidatePath_DoublePeriod() { assertThrows(IllegalArgumentException.class, () -> { PathUtils.validatePath("/double/../period"); }); }
@Test public void testValidatePath_NameContainingPeriod() { PathUtils.validatePath("/name/with.period."); }
@Test public void testValidatePath_0x01() { assertThrows(IllegalArgumentException.class, () -> { PathUtils.validatePath("/test\u0001"); }); }
@Test public void testValidatePath_0x1F() { assertThrows(IllegalArgumentException.class, () -> { PathUtils.validatePath("/test\u001F"); }); }
@Test public void testValidatePath_0x20() { PathUtils.validatePath("/test\u0020"); }
@Test public void testValidatePath_0x7e() { PathUtils.validatePath("/test\u007e"); }
@Test public void testValidatePath_0x7f() { assertThrows(IllegalArgumentException.class, () -> { PathUtils.validatePath("/test\u007f"); }); }
@Test public void testValidatePath_0x9f() { assertThrows(IllegalArgumentException.class, () -> { PathUtils.validatePath("/test\u009f"); }); }
@Test public void testValidatePath_ud800() { assertThrows(IllegalArgumentException.class, () -> { PathUtils.validatePath("/test\ud800"); }); }
@Test public void testValidatePath_uf8ff() { assertThrows(IllegalArgumentException.class, () -> { PathUtils.validatePath("/test\uf8ff"); }); }
@Test public void testValidatePath_HighestAllowableChar() { PathUtils.validatePath("/test\uffef"); }
@Test public void testValidatePath_SupplementaryChar() { assertThrows(IllegalArgumentException.class, () -> { PathUtils.validatePath("/test\ufff0"); }); }