How to use the waitress.utilities.BadRequest function in waitress

def test_received_bad_host_header(self):
        from waitress.utilities import BadRequest

        data = b"HTTP/1.0 GET /foobar\r\n Host: foo\r\n\r\n"
        result = self.parser.received(data)
        self.assertEqual(result, 36)
        self.assertTrue(self.parser.completed)
        self.assertEqual(self.parser.error.__class__, BadRequest)

from waitress.utilities import BadRequest

        data = (
            b"GET /foobar HTTP/1.1\r\n"
            b"Transfer-Encoding: chunked\r\n"
            b"X-Foo: 1\r\n"
            b"\r\n"
            b"garbage\r\n"
        )
        # header
        result = self.parser.received(data)
        # body
        result = self.parser.received(data[result:])
        self.assertEqual(result, 9)
        self.assertTrue(self.parser.completed)
        self.assertTrue(isinstance(self.parser.error, BadRequest))

def test_received_chunk_not_properly_terminated(self):
        from waitress.utilities import BadRequest

        buf = DummyBuffer()
        inst = self._makeOne(buf)
        data = b"4\r\nWikibadchunk\r\n"
        result = inst.received(data)
        self.assertEqual(result, len(data))
        self.assertEqual(inst.completed, False)
        self.assertEqual(buf.data[0], b"Wiki")
        self.assertEqual(inst.error.__class__, BadRequest)

self.validate_chunk_end = True
            elif self.validate_chunk_end:
                s = self.chunk_end + s

                pos = s.find(b"\r\n")

                if pos < 0 and len(s) < 2:
                    self.chunk_end = s
                    s = b""
                else:
                    self.chunk_end = b""
                    if pos == 0:
                        # Chop off the terminating CR LF from the chunk
                        s = s[2:]
                    else:
                        self.error = BadRequest("Chunk not properly terminated")
                        self.all_chunks_received = True

                    # Always exit this loop
                    self.validate_chunk_end = False
            elif not self.all_chunks_received:
                # Receive a control line.
                s = self.control_line + s
                pos = s.find(b"\r\n")

                if pos < 0:
                    # Control line not finished.
                    self.control_line = s
                    s = b""
                else:
                    # Control line finished.
                    line = s[:pos]

header_plus = s[:index]

                # Remove preceeding blank lines. This is suggested by
                # https://tools.ietf.org/html/rfc7230#section-3.5 to support
                # clients sending an extra CR LF after another request when
                # using HTTP pipelining
                header_plus = header_plus.lstrip()

                if not header_plus:
                    self.empty = True
                    self.completed = True
                else:
                    try:
                        self.parse_header(header_plus)
                    except ParsingError as e:
                        self.error = BadRequest(e.args[0])
                        self.completed = True
                    except TransferEncodingNotImplemented as e:
                        self.error = ServerNotImplemented(e.args[0])
                        self.completed = True
                    else:
                        if self.body_rcv is None:
                            # no content-length header and not a t-e: chunked
                            # request
                            self.completed = True

                        if self.content_length > 0:
                            max_body = self.adj.max_request_body_size
                            # we won't accept this request if the content-length
                            # is too large

                            if self.content_length >= max_body:

line = s[:pos]
                    s = s[pos + 2 :]
                    self.control_line = b""
                    line = line.strip()

                    if line:
                        # Begin a new chunk.
                        semi = line.find(b";")

                        if semi >= 0:
                            # discard extension info.
                            line = line[:semi]
                        try:
                            sz = int(line.strip(), 16)  # hexadecimal
                        except ValueError:  # garbage in input
                            self.error = BadRequest("garbage in chunked encoding input")
                            sz = 0

                        if sz > 0:
                            # Start a new chunk.
                            self.chunk_remainder = sz
                        else:
                            # Finished chunks.
                            self.all_chunks_received = True
                    # else expect a control line.
            else:
                # Receive the trailer.
                trailer = self.trailer + s

                if trailer.startswith(b"\r\n"):
                    # No trailer.
                    self.completed = True

s = self.header_plus + data
            index = find_double_newline(s)
            if index >= 0:
                # Header finished.
                header_plus = s[:index]
                consumed = len(data) - (len(s) - index)
                # Remove preceeding blank lines.
                header_plus = header_plus.lstrip()
                if not header_plus:
                    self.empty = True
                    self.completed = True
                else:
                    try:
                        self.parse_header(header_plus)
                    except ParsingError as e:
                        self.error = BadRequest(e.args[0])
                        self.completed = True
                    else:
                        if self.body_rcv is None:
                            # no content-length header and not a t-e: chunked
                            # request
                            self.completed = True
                        if self.content_length > 0:
                            max_body = self.adj.max_request_body_size
                            # we won't accept this request if the content-length
                            # is too large
                            if self.content_length >= max_body:
                                self.error = RequestEntityTooLarge(
                                    'exceeds max_body of %s' % max_body)
                                self.completed = True
                self.headers_finished = True
                return consumed

line = s[:pos]
                    s = s[pos + 2 :]
                    self.control_line = b""
                    line = line.strip()

                    if line:
                        # Begin a new chunk.
                        semi = line.find(b";")

                        if semi >= 0:
                            # discard extension info.
                            line = line[:semi]
                        try:
                            sz = int(line.strip(), 16)  # hexadecimal
                        except ValueError:  # garbage in input
                            self.error = BadRequest("garbage in chunked encoding input")
                            sz = 0

                        if sz > 0:
                            # Start a new chunk.
                            self.chunk_remainder = sz
                        else:
                            # Finished chunks.
                            self.all_chunks_received = True
                    # else expect a control line.
            else:
                # Receive the trailer.
                trailer = self.trailer + s

                if trailer.startswith(b"\r\n"):
                    # No trailer.
                    self.completed = True

self.validate_chunk_end = True
            elif self.validate_chunk_end:
                s = self.chunk_end + s

                pos = s.find(b"\r\n")

                if pos < 0 and len(s) < 2:
                    self.chunk_end = s
                    s = b""
                else:
                    self.chunk_end = b""
                    if pos == 0:
                        # Chop off the terminating CR LF from the chunk
                        s = s[2:]
                    else:
                        self.error = BadRequest("Chunk not properly terminated")
                        self.all_chunks_received = True

                    # Always exit this loop
                    self.validate_chunk_end = False
            elif not self.all_chunks_received:
                # Receive a control line.
                s = self.control_line + s
                pos = s.find(b"\r\n")

                if pos < 0:
                    # Control line not finished.
                    self.control_line = s
                    s = b""
                else:
                    # Control line finished.
                    line = s[:pos]