Lib/test/test_tokenize.py

from test import support
from tokenize import (tokenize, _tokenize, untokenize, NUMBER, NAME, OP,
                     STRING, ENDMARKER, ENCODING, tok_name, detect_encoding,
                     open as tokenize_open, Untokenizer)
from io import BytesIO
from unittest import TestCase, mock
import os
import token


class TokenizeTest(TestCase):
    # Tests for the tokenize module.

    # The tests can be really simple. Given a small fragment of source
    # code, print out a table with tokens. The ENDMARKER is omitted for
    # brevity.

    def check_tokenize(self, s, expected):
        # Format the tokens in s in a table format.
        # The ENDMARKER is omitted.
        result = []
        f = BytesIO(s.encode('utf-8'))
        for type, token, start, end, line in tokenize(f.readline):
            if type == ENDMARKER:
                break
            type = tok_name[type]
            result.append("    %(type)-10.10s %(token)-13.13r %(start)s %(end)s" %
                          locals())
        self.assertEqual(result,
                         ["    ENCODING   'utf-8'       (0, 0) (0, 0)"] +
                         expected.rstrip().splitlines())

    def test_basic(self):
        self.check_tokenize("1 + 1", """\
    NUMBER     '1'           (1, 0) (1, 1)
    OP         '+'           (1, 2) (1, 3)
    NUMBER     '1'           (1, 4) (1, 5)
    """)
        self.check_tokenize("if False:\n"
                            "    # NL\n"
                            "    True = False # NEWLINE\n", """\
    NAME       'if'          (1, 0) (1, 2)
    NAME       'False'       (1, 3) (1, 8)
    OP         ':'           (1, 8) (1, 9)
    NEWLINE    '\\n'          (1, 9) (1, 10)
    COMMENT    '# NL'        (2, 4) (2, 8)
    NL         '\\n'          (2, 8) (2, 9)
    INDENT     '    '        (3, 0) (3, 4)
    NAME       'True'        (3, 4) (3, 8)
    OP         '='           (3, 9) (3, 10)
    NAME       'False'       (3, 11) (3, 16)
    COMMENT    '# NEWLINE'   (3, 17) (3, 26)
    NEWLINE    '\\n'          (3, 26) (3, 27)
    DEDENT     ''            (4, 0) (4, 0)
    """)
        indent_error_file = b"""\
def k(x):
    x += 2
  x += 5
"""
        readline = BytesIO(indent_error_file).readline
        with self.assertRaisesRegex(IndentationError,
                                    "unindent does not match any "
                                    "outer indentation level"):
            for tok in tokenize(readline):
                pass

    def test_int(self):
        # Ordinary integers and binary operators
        self.check_tokenize("0xff <= 255", """\
    NUMBER     '0xff'        (1, 0) (1, 4)
    OP         '<='          (1, 5) (1, 7)
    NUMBER     '255'         (1, 8) (1, 11)
    """)
        self.check_tokenize("0b10 <= 255", """\
    NUMBER     '0b10'        (1, 0) (1, 4)
    OP         '<='          (1, 5) (1, 7)
    NUMBER     '255'         (1, 8) (1, 11)
    """)
        self.check_tokenize("0o123 <= 0O123", """\
    NUMBER     '0o123'       (1, 0) (1, 5)
    OP         '<='          (1, 6) (1, 8)
    NUMBER     '0O123'       (1, 9) (1, 14)
    """)
        self.check_tokenize("1234567 > ~0x15", """\
    NUMBER     '1234567'     (1, 0) (1, 7)
    OP         '>'           (1, 8) (1, 9)
    OP         '~'           (1, 10) (1, 11)
    NUMBER     '0x15'        (1, 11) (1, 15)
    """)
        self.check_tokenize("2134568 != 1231515", """\
    NUMBER     '2134568'     (1, 0) (1, 7)
    OP         '!='          (1, 8) (1, 10)
    NUMBER     '1231515'     (1, 11) (1, 18)
    """)
        self.check_tokenize("(-124561-1) & 200000000", """\
    OP         '('           (1, 0) (1, 1)
    OP         '-'           (1, 1) (1, 2)
    NUMBER     '124561'      (1, 2) (1, 8)
    OP         '-'           (1, 8) (1, 9)
    NUMBER     '1'           (1, 9) (1, 10)
    OP         ')'           (1, 10) (1, 11)
    OP         '&'           (1, 12) (1, 13)
    NUMBER     '200000000'   (1, 14) (1, 23)
    """)
        self.check_tokenize("0xdeadbeef != -1", """\
    NUMBER     '0xdeadbeef'  (1, 0) (1, 10)
    OP         '!='          (1, 11) (1, 13)
    OP         '-'           (1, 14) (1, 15)
    NUMBER     '1'           (1, 15) (1, 16)
    """)
        self.check_tokenize("0xdeadc0de & 12345", """\
    NUMBER     '0xdeadc0de'  (1, 0) (1, 10)
    OP         '&'           (1, 11) (1, 12)
    NUMBER     '12345'       (1, 13) (1, 18)
    """)
        self.check_tokenize("0xFF & 0x15 | 1234", """\
    NUMBER     '0xFF'        (1, 0) (1, 4)
    OP         '&'           (1, 5) (1, 6)
    NUMBER     '0x15'        (1, 7) (1, 11)
    OP         '|'           (1, 12) (1, 13)
    NUMBER     '1234'        (1, 14) (1, 18)
    """)

    def test_long(self):
        # Long integers
        self.check_tokenize("x = 0", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    NUMBER     '0'           (1, 4) (1, 5)
    """)
        self.check_tokenize("x = 0xfffffffffff", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    NUMBER     '0xffffffffff (1, 4) (1, 17)
    """)
        self.check_tokenize("x = 123141242151251616110", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    NUMBER     '123141242151 (1, 4) (1, 25)
    """)
        self.check_tokenize("x = -15921590215012591", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    OP         '-'           (1, 4) (1, 5)
    NUMBER     '159215902150 (1, 5) (1, 22)
    """)

    def test_float(self):
        # Floating point numbers
        self.check_tokenize("x = 3.14159", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    NUMBER     '3.14159'     (1, 4) (1, 11)
    """)
        self.check_tokenize("x = 314159.", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    NUMBER     '314159.'     (1, 4) (1, 11)
    """)
        self.check_tokenize("x = .314159", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    NUMBER     '.314159'     (1, 4) (1, 11)
    """)
        self.check_tokenize("x = 3e14159", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    NUMBER     '3e14159'     (1, 4) (1, 11)
    """)
        self.check_tokenize("x = 3E123", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    NUMBER     '3E123'       (1, 4) (1, 9)
    """)
        self.check_tokenize("x+y = 3e-1230", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '+'           (1, 1) (1, 2)
    NAME       'y'           (1, 2) (1, 3)
    OP         '='           (1, 4) (1, 5)
    NUMBER     '3e-1230'     (1, 6) (1, 13)
    """)
        self.check_tokenize("x = 3.14e159", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    NUMBER     '3.14e159'    (1, 4) (1, 12)
    """)

    def test_string(self):
        # String literals
        self.check_tokenize("x = ''; y = \"\"", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    STRING     "''"          (1, 4) (1, 6)
    OP         ';'           (1, 6) (1, 7)
    NAME       'y'           (1, 8) (1, 9)
    OP         '='           (1, 10) (1, 11)
    STRING     '""'          (1, 12) (1, 14)
    """)
        self.check_tokenize("x = '\"'; y = \"'\"", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    STRING     '\\'"\\''       (1, 4) (1, 7)
    OP         ';'           (1, 7) (1, 8)
    NAME       'y'           (1, 9) (1, 10)
    OP         '='           (1, 11) (1, 12)
    STRING     '"\\'"'        (1, 13) (1, 16)
    """)
        self.check_tokenize("x = \"doesn't \"shrink\", does it\"", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    STRING     '"doesn\\'t "' (1, 4) (1, 14)
    NAME       'shrink'      (1, 14) (1, 20)
    STRING     '", does it"' (1, 20) (1, 31)
    """)
        self.check_tokenize("x = 'abc' + 'ABC'", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    STRING     "'abc'"       (1, 4) (1, 9)
    OP         '+'           (1, 10) (1, 11)
    STRING     "'ABC'"       (1, 12) (1, 17)
    """)
        self.check_tokenize('y = "ABC" + "ABC"', """\
    NAME       'y'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    STRING     '"ABC"'       (1, 4) (1, 9)
    OP         '+'           (1, 10) (1, 11)
    STRING     '"ABC"'       (1, 12) (1, 17)
    """)
        self.check_tokenize("x = r'abc' + r'ABC' + R'ABC' + R'ABC'", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    STRING     "r'abc'"      (1, 4) (1, 10)
    OP         '+'           (1, 11) (1, 12)
    STRING     "r'ABC'"      (1, 13) (1, 19)
    OP         '+'           (1, 20) (1, 21)
    STRING     "R'ABC'"      (1, 22) (1, 28)
    OP         '+'           (1, 29) (1, 30)
    STRING     "R'ABC'"      (1, 31) (1, 37)
    """)
        self.check_tokenize('y = r"abc" + r"ABC" + R"ABC" + R"ABC"', """\
    NAME       'y'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    STRING     'r"abc"'      (1, 4) (1, 10)
    OP         '+'           (1, 11) (1, 12)
    STRING     'r"ABC"'      (1, 13) (1, 19)
    OP         '+'           (1, 20) (1, 21)
    STRING     'R"ABC"'      (1, 22) (1, 28)
    OP         '+'           (1, 29) (1, 30)
    STRING     'R"ABC"'      (1, 31) (1, 37)
    """)

        self.check_tokenize("u'abc' + U'abc'", """\
    STRING     "u'abc'"      (1, 0) (1, 6)
    OP         '+'           (1, 7) (1, 8)
    STRING     "U'abc'"      (1, 9) (1, 15)
    """)
        self.check_tokenize('u"abc" + U"abc"', """\
    STRING     'u"abc"'      (1, 0) (1, 6)
    OP         '+'           (1, 7) (1, 8)
    STRING     'U"abc"'      (1, 9) (1, 15)
    """)

        self.check_tokenize("b'abc' + B'abc'", """\
    STRING     "b'abc'"      (1, 0) (1, 6)
    OP         '+'           (1, 7) (1, 8)
    STRING     "B'abc'"      (1, 9) (1, 15)
    """)
        self.check_tokenize('b"abc" + B"abc"', """\
    STRING     'b"abc"'      (1, 0) (1, 6)
    OP         '+'           (1, 7) (1, 8)
    STRING     'B"abc"'      (1, 9) (1, 15)
    """)
        self.check_tokenize("br'abc' + bR'abc' + Br'abc' + BR'abc'", """\
    STRING     "br'abc'"     (1, 0) (1, 7)
    OP         '+'           (1, 8) (1, 9)
    STRING     "bR'abc'"     (1, 10) (1, 17)
    OP         '+'           (1, 18) (1, 19)
    STRING     "Br'abc'"     (1, 20) (1, 27)
    OP         '+'           (1, 28) (1, 29)
    STRING     "BR'abc'"     (1, 30) (1, 37)
    """)
        self.check_tokenize('br"abc" + bR"abc" + Br"abc" + BR"abc"', """\
    STRING     'br"abc"'     (1, 0) (1, 7)
    OP         '+'           (1, 8) (1, 9)
    STRING     'bR"abc"'     (1, 10) (1, 17)
    OP         '+'           (1, 18) (1, 19)
    STRING     'Br"abc"'     (1, 20) (1, 27)
    OP         '+'           (1, 28) (1, 29)
    STRING     'BR"abc"'     (1, 30) (1, 37)
    """)
        self.check_tokenize("rb'abc' + rB'abc' + Rb'abc' + RB'abc'", """\
    STRING     "rb'abc'"     (1, 0) (1, 7)
    OP         '+'           (1, 8) (1, 9)
    STRING     "rB'abc'"     (1, 10) (1, 17)
    OP         '+'           (1, 18) (1, 19)
    STRING     "Rb'abc'"     (1, 20) (1, 27)
    OP         '+'           (1, 28) (1, 29)
    STRING     "RB'abc'"     (1, 30) (1, 37)
    """)
        self.check_tokenize('rb"abc" + rB"abc" + Rb"abc" + RB"abc"', """\
    STRING     'rb"abc"'     (1, 0) (1, 7)
    OP         '+'           (1, 8) (1, 9)
    STRING     'rB"abc"'     (1, 10) (1, 17)
    OP         '+'           (1, 18) (1, 19)
    STRING     'Rb"abc"'     (1, 20) (1, 27)
    OP         '+'           (1, 28) (1, 29)
    STRING     'RB"abc"'     (1, 30) (1, 37)
    """)

    def test_function(self):
        self.check_tokenize("def d22(a, b, c=2, d=2, *k): pass", """\
    NAME       'def'         (1, 0) (1, 3)
    NAME       'd22'         (1, 4) (1, 7)
    OP         '('           (1, 7) (1, 8)
    NAME       'a'           (1, 8) (1, 9)
    OP         ','           (1, 9) (1, 10)
    NAME       'b'           (1, 11) (1, 12)
    OP         ','           (1, 12) (1, 13)
    NAME       'c'           (1, 14) (1, 15)
    OP         '='           (1, 15) (1, 16)
    NUMBER     '2'           (1, 16) (1, 17)
    OP         ','           (1, 17) (1, 18)
    NAME       'd'           (1, 19) (1, 20)
    OP         '='           (1, 20) (1, 21)
    NUMBER     '2'           (1, 21) (1, 22)
    OP         ','           (1, 22) (1, 23)
    OP         '*'           (1, 24) (1, 25)
    NAME       'k'           (1, 25) (1, 26)
    OP         ')'           (1, 26) (1, 27)
    OP         ':'           (1, 27) (1, 28)
    NAME       'pass'        (1, 29) (1, 33)
    """)
        self.check_tokenize("def d01v_(a=1, *k, **w): pass", """\
    NAME       'def'         (1, 0) (1, 3)
    NAME       'd01v_'       (1, 4) (1, 9)
    OP         '('           (1, 9) (1, 10)
    NAME       'a'           (1, 10) (1, 11)
    OP         '='           (1, 11) (1, 12)
    NUMBER     '1'           (1, 12) (1, 13)
    OP         ','           (1, 13) (1, 14)
    OP         '*'           (1, 15) (1, 16)
    NAME       'k'           (1, 16) (1, 17)
    OP         ','           (1, 17) (1, 18)
    OP         '**'          (1, 19) (1, 21)
    NAME       'w'           (1, 21) (1, 22)
    OP         ')'           (1, 22) (1, 23)
    OP         ':'           (1, 23) (1, 24)
    NAME       'pass'        (1, 25) (1, 29)
    """)

    def test_comparison(self):
        # Comparison
        self.check_tokenize("if 1 < 1 > 1 == 1 >= 5 <= 0x15 <= 0x12 != "
                            "1 and 5 in 1 not in 1 is 1 or 5 is not 1: pass", """\
    NAME       'if'          (1, 0) (1, 2)
    NUMBER     '1'           (1, 3) (1, 4)
    OP         '<'           (1, 5) (1, 6)
    NUMBER     '1'           (1, 7) (1, 8)
    OP         '>'           (1, 9) (1, 10)
    NUMBER     '1'           (1, 11) (1, 12)
    OP         '=='          (1, 13) (1, 15)
    NUMBER     '1'           (1, 16) (1, 17)
    OP         '>='          (1, 18) (1, 20)
    NUMBER     '5'           (1, 21) (1, 22)
    OP         '<='          (1, 23) (1, 25)
    NUMBER     '0x15'        (1, 26) (1, 30)
    OP         '<='          (1, 31) (1, 33)
    NUMBER     '0x12'        (1, 34) (1, 38)
    OP         '!='          (1, 39) (1, 41)
    NUMBER     '1'           (1, 42) (1, 43)
    NAME       'and'         (1, 44) (1, 47)
    NUMBER     '5'           (1, 48) (1, 49)
    NAME       'in'          (1, 50) (1, 52)
    NUMBER     '1'           (1, 53) (1, 54)
    NAME       'not'         (1, 55) (1, 58)
    NAME       'in'          (1, 59) (1, 61)
    NUMBER     '1'           (1, 62) (1, 63)
    NAME       'is'          (1, 64) (1, 66)
    NUMBER     '1'           (1, 67) (1, 68)
    NAME       'or'          (1, 69) (1, 71)
    NUMBER     '5'           (1, 72) (1, 73)
    NAME       'is'          (1, 74) (1, 76)
    NAME       'not'         (1, 77) (1, 80)
    NUMBER     '1'           (1, 81) (1, 82)
    OP         ':'           (1, 82) (1, 83)
    NAME       'pass'        (1, 84) (1, 88)
    """)

    def test_shift(self):
        # Shift
        self.check_tokenize("x = 1 << 1 >> 5", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    NUMBER     '1'           (1, 4) (1, 5)
    OP         '<<'          (1, 6) (1, 8)
    NUMBER     '1'           (1, 9) (1, 10)
    OP         '>>'          (1, 11) (1, 13)
    NUMBER     '5'           (1, 14) (1, 15)
    """)

    def test_additive(self):
        # Additive
        self.check_tokenize("x = 1 - y + 15 - 1 + 0x124 + z + a[5]", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    NUMBER     '1'           (1, 4) (1, 5)
    OP         '-'           (1, 6) (1, 7)
    NAME       'y'           (1, 8) (1, 9)
    OP         '+'           (1, 10) (1, 11)
    NUMBER     '15'          (1, 12) (1, 14)
    OP         '-'           (1, 15) (1, 16)
    NUMBER     '1'           (1, 17) (1, 18)
    OP         '+'           (1, 19) (1, 20)
    NUMBER     '0x124'       (1, 21) (1, 26)
    OP         '+'           (1, 27) (1, 28)
    NAME       'z'           (1, 29) (1, 30)
    OP         '+'           (1, 31) (1, 32)
    NAME       'a'           (1, 33) (1, 34)
    OP         '['           (1, 34) (1, 35)
    NUMBER     '5'           (1, 35) (1, 36)
    OP         ']'           (1, 36) (1, 37)
    """)

    def test_multiplicative(self):
        # Multiplicative
        self.check_tokenize("x = 1//1*1/5*12%0x12", """\
    NAME       'x'           (1, 0) (1, 1)
    OP         '='           (1, 2) (1, 3)
    NUMBER     '1'           (1, 4) (1, 5)
    OP         '//'          (1, 5) (1, 7)
    NUMBER     '1'           (1, 7) (1, 8)
    OP         '*'           (1, 8) (1, 9)
    NUMBER     '1'           (1, 9) (1, 10)
    OP         '/'           (1, 10) (1, 11)
    NUMBER     '5'           (1, 11) (1, 12)
    OP         '*'           (1, 12) (1, 13)
    NUMBER     '12'          (1, 13) (1, 15)
    OP         '%'           (1, 15) (1, 16)
    NUMBER     '0x12'        (1, 16) (1, 20)
    """)

    def test_unary(self):
        # Unary
        self.check_tokenize("~1 ^ 1 & 1 |1 ^ -1", """\
    OP         '~'           (1, 0) (1, 1)
    NUMBER     '1'           (1, 1) (1, 2)
    OP         '^'           (1, 3) (1, 4)
    NUMBER     '1'           (1, 5) (1, 6)
    OP         '&'           (1, 7) (1, 8)
    NUMBER     '1'           (1, 9) (1, 10)
    OP         '|'           (1, 11) (1, 12)
    NUMBER     '1'           (1, 12) (1, 13)
    OP         '^'           (1, 14) (1, 15)
    OP         '-'           (1, 16) (1, 17)
    NUMBER     '1'           (1, 17) (1, 18)
    """)
        self.check_tokenize("-1*1/1+1*1//1 - ---1**1", """\
    OP         '-'           (1, 0) (1, 1)
    NUMBER     '1'           (1, 1) (1, 2)
    OP         '*'           (1, 2) (1, 3)
    NUMBER     '1'           (1, 3) (1, 4)
    OP         '/'           (1, 4) (1, 5)
    NUMBER     '1'           (1, 5) (1, 6)
    OP         '+'           (1, 6) (1, 7)
    NUMBER     '1'           (1, 7) (1, 8)
    OP         '*'           (1, 8) (1, 9)
    NUMBER     '1'           (1, 9) (1, 10)
    OP         '//'          (1, 10) (1, 12)
    NUMBER     '1'           (1, 12) (1, 13)
    OP         '-'           (1, 14) (1, 15)
    OP         '-'           (1, 16) (1, 17)
    OP         '-'           (1, 17) (1, 18)
    OP         '-'           (1, 18) (1, 19)
    NUMBER     '1'           (1, 19) (1, 20)
    OP         '**'          (1, 20) (1, 22)
    NUMBER     '1'           (1, 22) (1, 23)
    """)

    def test_selector(self):
        # Selector
        self.check_tokenize("import sys, time\nx = sys.modules['time'].time()", """\
    NAME       'import'      (1, 0) (1, 6)
    NAME       'sys'         (1, 7) (1, 10)
    OP         ','           (1, 10) (1, 11)
    NAME       'time'        (1, 12) (1, 16)
    NEWLINE    '\\n'          (1, 16) (1, 17)
    NAME       'x'           (2, 0) (2, 1)
    OP         '='           (2, 2) (2, 3)
    NAME       'sys'         (2, 4) (2, 7)
    OP         '.'           (2, 7) (2, 8)
    NAME       'modules'     (2, 8) (2, 15)
    OP         '['           (2, 15) (2, 16)
    STRING     "'time'"      (2, 16) (2, 22)
    OP         ']'           (2, 22) (2, 23)
    OP         '.'           (2, 23) (2, 24)
    NAME       'time'        (2, 24) (2, 28)
    OP         '('           (2, 28) (2, 29)
    OP         ')'           (2, 29) (2, 30)
    """)

    def test_method(self):
        # Methods
        self.check_tokenize("@staticmethod\ndef foo(x,y): pass", """\
    OP         '@'           (1, 0) (1, 1)
    NAME       'staticmethod (1, 1) (1, 13)
    NEWLINE    '\\n'          (1, 13) (1, 14)
    NAME       'def'         (2, 0) (2, 3)
    NAME       'foo'         (2, 4) (2, 7)
    OP         '('           (2, 7) (2, 8)
    NAME       'x'           (2, 8) (2, 9)
    OP         ','           (2, 9) (2, 10)
    NAME       'y'           (2, 10) (2, 11)
    OP         ')'           (2, 11) (2, 12)
    OP         ':'           (2, 12) (2, 13)
    NAME       'pass'        (2, 14) (2, 18)
    """)

    def test_tabs(self):
        # Evil tabs
        self.check_tokenize("def f():\n"
                            "\tif x\n"
                            "        \tpass", """\
    NAME       'def'         (1, 0) (1, 3)
    NAME       'f'           (1, 4) (1, 5)
    OP         '('           (1, 5) (1, 6)
    OP         ')'           (1, 6) (1, 7)
    OP         ':'           (1, 7) (1, 8)
    NEWLINE    '\\n'          (1, 8) (1, 9)
    INDENT     '\\t'          (2, 0) (2, 1)
    NAME       'if'          (2, 1) (2, 3)
    NAME       'x'           (2, 4) (2, 5)
    NEWLINE    '\\n'          (2, 5) (2, 6)
    INDENT     '        \\t'  (3, 0) (3, 9)
    NAME       'pass'        (3, 9) (3, 13)
    DEDENT     ''            (4, 0) (4, 0)
    DEDENT     ''            (4, 0) (4, 0)
    """)

    def test_non_ascii_identifiers(self):
        # Non-ascii identifiers
        self.check_tokenize("Örter = 'places'\ngrün = 'green'", """\
    NAME       'Örter'       (1, 0) (1, 5)
    OP         '='           (1, 6) (1, 7)
    STRING     "'places'"    (1, 8) (1, 16)
    NEWLINE    '\\n'          (1, 16) (1, 17)
    NAME       'grün'        (2, 0) (2, 4)
    OP         '='           (2, 5) (2, 6)
    STRING     "'green'"     (2, 7) (2, 14)
    """)

    def test_unicode(self):
        # Legacy unicode literals:
        self.check_tokenize("Örter = u'places'\ngrün = U'green'", """\
    NAME       'Örter'       (1, 0) (1, 5)
    OP         '='           (1, 6) (1, 7)
    STRING     "u'places'"   (1, 8) (1, 17)
    NEWLINE    '\\n'          (1, 17) (1, 18)
    NAME       'grün'        (2, 0) (2, 4)
    OP         '='           (2, 5) (2, 6)
    STRING     "U'green'"    (2, 7) (2, 15)
    """)


def decistmt(s):
    result = []
    g = tokenize(BytesIO(s.encode('utf-8')).readline)   # tokenize the string
    for toknum, tokval, _, _, _  in g:
        if toknum == NUMBER and '.' in tokval:  # replace NUMBER tokens
            result.extend([
                (NAME, 'Decimal'),
                (OP, '('),
                (STRING, repr(tokval)),
                (OP, ')')
            ])
        else:
            result.append((toknum, tokval))
    return untokenize(result).decode('utf-8')

class TestMisc(TestCase):

    def test_decistmt(self):
        # Substitute Decimals for floats in a string of statements.
        # This is an example from the docs.

        from decimal import Decimal
        s = '+21.3e-5*-.1234/81.7'
        self.assertEqual(decistmt(s),
                         "+Decimal ('21.3e-5')*-Decimal ('.1234')/Decimal ('81.7')")

        # The format of the exponent is inherited from the platform C library.
        # Known cases are "e-007" (Windows) and "e-07" (not Windows).  Since
        # we're only showing 11 digits, and the 12th isn't close to 5, the
        # rest of the output should be platform-independent.
        self.assertRegex(repr(eval(s)), '-3.2171603427[0-9]*e-0+7')

        # Output from calculations with Decimal should be identical across all
        # platforms.
        self.assertEqual(eval(decistmt(s)),
                         Decimal('-3.217160342717258261933904529E-7'))


class TestTokenizerAdheresToPep0263(TestCase):
    """
    Test that tokenizer adheres to the coding behaviour stipulated in PEP 0263.
    """

    def _testFile(self, filename):
        path = os.path.join(os.path.dirname(__file__), filename)
        TestRoundtrip.check_roundtrip(self, open(path, 'rb'))

    def test_utf8_coding_cookie_and_no_utf8_bom(self):
        f = 'tokenize_tests-utf8-coding-cookie-and-no-utf8-bom-sig.txt'
        self._testFile(f)

    def test_latin1_coding_cookie_and_utf8_bom(self):
        """
        As per PEP 0263, if a file starts with a utf-8 BOM signature, the only
        allowed encoding for the comment is 'utf-8'.  The text file used in
        this test starts with a BOM signature, but specifies latin1 as the
        coding, so verify that a SyntaxError is raised, which matches the
        behaviour of the interpreter when it encounters a similar condition.
        """
        f = 'tokenize_tests-latin1-coding-cookie-and-utf8-bom-sig.txt'
        self.assertRaises(SyntaxError, self._testFile, f)

    def test_no_coding_cookie_and_utf8_bom(self):
        f = 'tokenize_tests-no-coding-cookie-and-utf8-bom-sig-only.txt'
        self._testFile(f)

    def test_utf8_coding_cookie_and_utf8_bom(self):
        f = 'tokenize_tests-utf8-coding-cookie-and-utf8-bom-sig.txt'
        self._testFile(f)

    def test_bad_coding_cookie(self):
        self.assertRaises(SyntaxError, self._testFile, 'bad_coding.py')
        self.assertRaises(SyntaxError, self._testFile, 'bad_coding2.py')


class Test_Tokenize(TestCase):

    def test__tokenize_decodes_with_specified_encoding(self):
        literal = '"ЉЊЈЁЂ"'
        line = literal.encode('utf-8')
        first = False
        def readline():
            nonlocal first
            if not first:
                first = True
                return line
            else:
                return b''

        # skip the initial encoding token and the end token
        tokens = list(_tokenize(readline, encoding='utf-8'))[1:-1]
        expected_tokens = [(3, '"ЉЊЈЁЂ"', (1, 0), (1, 7), '"ЉЊЈЁЂ"')]
        self.assertEqual(tokens, expected_tokens,
                         "bytes not decoded with encoding")

    def test__tokenize_does_not_decode_with_encoding_none(self):
        literal = '"ЉЊЈЁЂ"'
        first = False
        def readline():
            nonlocal first
            if not first:
                first = True
                return literal
            else:
                return b''

        # skip the end token
        tokens = list(_tokenize(readline, encoding=None))[:-1]
        expected_tokens = [(3, '"ЉЊЈЁЂ"', (1, 0), (1, 7), '"ЉЊЈЁЂ"')]
        self.assertEqual(tokens, expected_tokens,
                         "string not tokenized when encoding is None")


class TestDetectEncoding(TestCase):

    def get_readline(self, lines):
        index = 0
        def readline():
            nonlocal index
            if index == len(lines):
                raise StopIteration
            line = lines[index]
            index += 1
            return line
        return readline

    def test_no_bom_no_encoding_cookie(self):
        lines = (
            b'# something\n',
            b'print(something)\n',
            b'do_something(else)\n'
        )
        encoding, consumed_lines = detect_encoding(self.get_readline(lines))
        self.assertEqual(encoding, 'utf-8')
        self.assertEqual(consumed_lines, list(lines[:2]))

    def test_bom_no_cookie(self):
        lines = (
            b'\xef\xbb\xbf# something\n',
            b'print(something)\n',
            b'do_something(else)\n'
        )
        encoding, consumed_lines = detect_encoding(self.get_readline(lines))
        self.assertEqual(encoding, 'utf-8-sig')
        self.assertEqual(consumed_lines,
                         [b'# something\n', b'print(something)\n'])

    def test_cookie_first_line_no_bom(self):
        lines = (
            b'# -*- coding: latin-1 -*-\n',
            b'print(something)\n',
            b'do_something(else)\n'
        )
        encoding, consumed_lines = detect_encoding(self.get_readline(lines))
        self.assertEqual(encoding, 'iso-8859-1')
        self.assertEqual(consumed_lines, [b'# -*- coding: latin-1 -*-\n'])

    def test_matched_bom_and_cookie_first_line(self):
        lines = (
            b'\xef\xbb\xbf# coding=utf-8\n',
            b'print(something)\n',
            b'do_something(else)\n'
        )
        encoding, consumed_lines = detect_encoding(self.get_readline(lines))
        self.assertEqual(encoding, 'utf-8-sig')
        self.assertEqual(consumed_lines, [b'# coding=utf-8\n'])

    def test_mismatched_bom_and_cookie_first_line_raises_syntaxerror(self):
        lines = (
            b'\xef\xbb\xbf# vim: set fileencoding=ascii :\n',
            b'print(something)\n',
            b'do_something(else)\n'
        )
        readline = self.get_readline(lines)
        self.assertRaises(SyntaxError, detect_encoding, readline)

    def test_cookie_second_line_no_bom(self):
        lines = (
            b'#! something\n',
            b'# vim: set fileencoding=ascii :\n',
            b'print(something)\n',
            b'do_something(else)\n'
        )
        encoding, consumed_lines = detect_encoding(self.get_readline(lines))
        self.assertEqual(encoding, 'ascii')
        expected = [b'#! something\n', b'# vim: set fileencoding=ascii :\n']
        self.assertEqual(consumed_lines, expected)

    def test_matched_bom_and_cookie_second_line(self):
        lines = (
            b'\xef\xbb\xbf#! something\n',
            b'f# coding=utf-8\n',
            b'print(something)\n',
            b'do_something(else)\n'
        )
        encoding, consumed_lines = detect_encoding(self.get_readline(lines))
        self.assertEqual(encoding, 'utf-8-sig')
        self.assertEqual(consumed_lines,
                         [b'#! something\n', b'f# coding=utf-8\n'])

    def test_mismatched_bom_and_cookie_second_line_raises_syntaxerror(self):
        lines = (
            b'\xef\xbb\xbf#! something\n',
            b'# vim: set fileencoding=ascii :\n',
            b'print(something)\n',
            b'do_something(else)\n'
        )
        readline = self.get_readline(lines)
        self.assertRaises(SyntaxError, detect_encoding, readline)

    def test_cookie_second_line_noncommented_first_line(self):
        lines = (
            b"print('\xc2\xa3')\n",
            b'# vim: set fileencoding=iso8859-15 :\n',
            b"print('\xe2\x82\xac')\n"
        )
        encoding, consumed_lines = detect_encoding(self.get_readline(lines))
        self.assertEqual(encoding, 'utf-8')
        expected = [b"print('\xc2\xa3')\n"]
        self.assertEqual(consumed_lines, expected)

    def test_cookie_second_line_commented_first_line(self):
        lines = (
            b"#print('\xc2\xa3')\n",
            b'# vim: set fileencoding=iso8859-15 :\n',
            b"print('\xe2\x82\xac')\n"
        )
        encoding, consumed_lines = detect_encoding(self.get_readline(lines))
        self.assertEqual(encoding, 'iso8859-15')
        expected = [b"#print('\xc2\xa3')\n", b'# vim: set fileencoding=iso8859-15 :\n']
        self.assertEqual(consumed_lines, expected)

    def test_cookie_second_line_empty_first_line(self):
        lines = (
            b'\n',
            b'# vim: set fileencoding=iso8859-15 :\n',
            b"print('\xe2\x82\xac')\n"
        )
        encoding, consumed_lines = detect_encoding(self.get_readline(lines))
        self.assertEqual(encoding, 'iso8859-15')
        expected = [b'\n', b'# vim: set fileencoding=iso8859-15 :\n']
        self.assertEqual(consumed_lines, expected)

    def test_latin1_normalization(self):
        # See get_normal_name() in tokenizer.c.
        encodings = ("latin-1", "iso-8859-1", "iso-latin-1", "latin-1-unix",
                     "iso-8859-1-unix", "iso-latin-1-mac")
        for encoding in encodings:
            for rep in ("-", "_"):
                enc = encoding.replace("-", rep)
                lines = (b"#!/usr/bin/python\n",
                         b"# coding: " + enc.encode("ascii") + b"\n",
                         b"print(things)\n",
                         b"do_something += 4\n")
                rl = self.get_readline(lines)
                found, consumed_lines = detect_encoding(rl)
                self.assertEqual(found, "iso-8859-1")

    def test_syntaxerror_latin1(self):
        # Issue 14629: need to raise SyntaxError if the first
        # line(s) have non-UTF-8 characters
        lines = (
            b'print("\xdf")', # Latin-1: LATIN SMALL LETTER SHARP S
            )
        readline = self.get_readline(lines)
        self.assertRaises(SyntaxError, detect_encoding, readline)


    def test_utf8_normalization(self):
        # See get_normal_name() in tokenizer.c.
        encodings = ("utf-8", "utf-8-mac", "utf-8-unix")
        for encoding in encodings:
            for rep in ("-", "_"):
                enc = encoding.replace("-", rep)
                lines = (b"#!/usr/bin/python\n",
                         b"# coding: " + enc.encode("ascii") + b"\n",
                         b"1 + 3\n")
                rl = self.get_readline(lines)
                found, consumed_lines = detect_encoding(rl)
                self.assertEqual(found, "utf-8")

    def test_short_files(self):
        readline = self.get_readline((b'print(something)\n',))
        encoding, consumed_lines = detect_encoding(readline)
        self.assertEqual(encoding, 'utf-8')
        self.assertEqual(consumed_lines, [b'print(something)\n'])

        encoding, consumed_lines = detect_encoding(self.get_readline(()))
        self.assertEqual(encoding, 'utf-8')
        self.assertEqual(consumed_lines, [])

        readline = self.get_readline((b'\xef\xbb\xbfprint(something)\n',))
        encoding, consumed_lines = detect_encoding(readline)
        self.assertEqual(encoding, 'utf-8-sig')
        self.assertEqual(consumed_lines, [b'print(something)\n'])

        readline = self.get_readline((b'\xef\xbb\xbf',))
        encoding, consumed_lines = detect_encoding(readline)
        self.assertEqual(encoding, 'utf-8-sig')
        self.assertEqual(consumed_lines, [])

        readline = self.get_readline((b'# coding: bad\n',))
        self.assertRaises(SyntaxError, detect_encoding, readline)

    def test_false_encoding(self):
        # Issue 18873: "Encoding" detected in non-comment lines
        readline = self.get_readline((b'print("#coding=fake")',))
        encoding, consumed_lines = detect_encoding(readline)
        self.assertEqual(encoding, 'utf-8')
        self.assertEqual(consumed_lines, [b'print("#coding=fake")'])

    def test_open(self):
        filename = support.TESTFN + '.py'
        self.addCleanup(support.unlink, filename)

        # test coding cookie
        for encoding in ('iso-8859-15', 'utf-8'):
            with open(filename, 'w', encoding=encoding) as fp:
                print("# coding: %s" % encoding, file=fp)
                print("print('euro:\u20ac')", file=fp)
            with tokenize_open(filename) as fp:
                self.assertEqual(fp.encoding, encoding)
                self.assertEqual(fp.mode, 'r')

        # test BOM (no coding cookie)
        with open(filename, 'w', encoding='utf-8-sig') as fp:
            print("print('euro:\u20ac')", file=fp)
        with tokenize_open(filename) as fp:
            self.assertEqual(fp.encoding, 'utf-8-sig')
            self.assertEqual(fp.mode, 'r')

    def test_filename_in_exception(self):
        # When possible, include the file name in the exception.
        path = 'some_file_path'
        lines = (
            b'print("\xdf")', # Latin-1: LATIN SMALL LETTER SHARP S
            )
        class Bunk:
            def __init__(self, lines, path):
                self.name = path
                self._lines = lines
                self._index = 0

            def readline(self):
                if self._index == len(lines):
                    raise StopIteration
                line = lines[self._index]
                self._index += 1
                return line

        with self.assertRaises(SyntaxError):
            ins = Bunk(lines, path)
            # Make sure lacking a name isn't an issue.
            del ins.name
            detect_encoding(ins.readline)
        with self.assertRaisesRegex(SyntaxError, '.*{}'.format(path)):
            ins = Bunk(lines, path)
            detect_encoding(ins.readline)

    def test_open_error(self):
        # Issue #23840: open() must close the binary file on error
        m = BytesIO(b'#coding:xxx')
        with mock.patch('tokenize._builtin_open', return_value=m):
            self.assertRaises(SyntaxError, tokenize_open, 'foobar')
        self.assertTrue(m.closed)


class TestTokenize(TestCase):

    def test_tokenize(self):
        import tokenize as tokenize_module
        encoding = object()
        encoding_used = None
        def mock_detect_encoding(readline):
            return encoding, [b'first', b'second']

        def mock__tokenize(readline, encoding):
            nonlocal encoding_used
            encoding_used = encoding
            out = []
            while True:
                next_line = readline()
                if next_line:
                    out.append(next_line)
                    continue
                return out

        counter = 0
        def mock_readline():
            nonlocal counter
            counter += 1
            if counter == 5:
                return b''
            return str(counter).encode()

        orig_detect_encoding = tokenize_module.detect_encoding
        orig__tokenize = tokenize_module._tokenize
        tokenize_module.detect_encoding = mock_detect_encoding
        tokenize_module._tokenize = mock__tokenize
        try:
            results = tokenize(mock_readline)
            self.assertEqual(list(results),
                             [b'first', b'second', b'1', b'2', b'3', b'4'])
        finally:
            tokenize_module.detect_encoding = orig_detect_encoding
            tokenize_module._tokenize = orig__tokenize

        self.assertTrue(encoding_used, encoding)

    def assertExactTypeEqual(self, opstr, *optypes):
        tokens = list(tokenize(BytesIO(opstr.encode('utf-8')).readline))
        num_optypes = len(optypes)
        self.assertEqual(len(tokens), 2 + num_optypes)
        self.assertEqual(token.tok_name[tokens[0].exact_type],
                         token.tok_name[ENCODING])
        for i in range(num_optypes):
            self.assertEqual(token.tok_name[tokens[i + 1].exact_type],
                             token.tok_name[optypes[i]])
        self.assertEqual(token.tok_name[tokens[1 + num_optypes].exact_type],
                         token.tok_name[token.ENDMARKER])

    def test_exact_type(self):
        self.assertExactTypeEqual('()', token.LPAR, token.RPAR)
        self.assertExactTypeEqual('[]', token.LSQB, token.RSQB)
        self.assertExactTypeEqual(':', token.COLON)
        self.assertExactTypeEqual(',', token.COMMA)
        self.assertExactTypeEqual(';', token.SEMI)
        self.assertExactTypeEqual('+', token.PLUS)
        self.assertExactTypeEqual('-', token.MINUS)
        self.assertExactTypeEqual('*', token.STAR)
        self.assertExactTypeEqual('/', token.SLASH)
        self.assertExactTypeEqual('|', token.VBAR)
        self.assertExactTypeEqual('&', token.AMPER)
        self.assertExactTypeEqual('<', token.LESS)
        self.assertExactTypeEqual('>', token.GREATER)
        self.assertExactTypeEqual('=', token.EQUAL)
        self.assertExactTypeEqual('.', token.DOT)
        self.assertExactTypeEqual('%', token.PERCENT)
        self.assertExactTypeEqual('{}', token.LBRACE, token.RBRACE)
        self.assertExactTypeEqual('==', token.EQEQUAL)
        self.assertExactTypeEqual('!=', token.NOTEQUAL)
        self.assertExactTypeEqual('<=', token.LESSEQUAL)
        self.assertExactTypeEqual('>=', token.GREATEREQUAL)
        self.assertExactTypeEqual('~', token.TILDE)
        self.assertExactTypeEqual('^', token.CIRCUMFLEX)
        self.assertExactTypeEqual('<<', token.LEFTSHIFT)
        self.assertExactTypeEqual('>>', token.RIGHTSHIFT)
        self.assertExactTypeEqual('**', token.DOUBLESTAR)
        self.assertExactTypeEqual('+=', token.PLUSEQUAL)
        self.assertExactTypeEqual('-=', token.MINEQUAL)
        self.assertExactTypeEqual('*=', token.STAREQUAL)
        self.assertExactTypeEqual('/=', token.SLASHEQUAL)
        self.assertExactTypeEqual('%=', token.PERCENTEQUAL)
        self.assertExactTypeEqual('&=', token.AMPEREQUAL)
        self.assertExactTypeEqual('|=', token.VBAREQUAL)
        self.assertExactTypeEqual('^=', token.CIRCUMFLEXEQUAL)
        self.assertExactTypeEqual('^=', token.CIRCUMFLEXEQUAL)
        self.assertExactTypeEqual('<<=', token.LEFTSHIFTEQUAL)
        self.assertExactTypeEqual('>>=', token.RIGHTSHIFTEQUAL)
        self.assertExactTypeEqual('**=', token.DOUBLESTAREQUAL)
        self.assertExactTypeEqual('//', token.DOUBLESLASH)
        self.assertExactTypeEqual('//=', token.DOUBLESLASHEQUAL)
        self.assertExactTypeEqual('@', token.AT)

        self.assertExactTypeEqual('a**2+b**2==c**2',
                                  NAME, token.DOUBLESTAR, NUMBER,
                                  token.PLUS,
                                  NAME, token.DOUBLESTAR, NUMBER,
                                  token.EQEQUAL,
                                  NAME, token.DOUBLESTAR, NUMBER)
        self.assertExactTypeEqual('{1, 2, 3}',
                                  token.LBRACE,
                                  token.NUMBER, token.COMMA,
                                  token.NUMBER, token.COMMA,
                                  token.NUMBER,
                                  token.RBRACE)
        self.assertExactTypeEqual('^(x & 0x1)',
                                  token.CIRCUMFLEX,
                                  token.LPAR,
                                  token.NAME, token.AMPER, token.NUMBER,
                                  token.RPAR)

    def test_pathological_trailing_whitespace(self):
        # See http://bugs.python.org/issue16152
        self.assertExactTypeEqual('@          ', token.AT)


class UntokenizeTest(TestCase):

    def test_bad_input_order(self):
        # raise if previous row
        u = Untokenizer()
        u.prev_row = 2
        u.prev_col = 2
        with self.assertRaises(ValueError) as cm:
            u.add_whitespace((1,3))
        self.assertEqual(cm.exception.args[0],
                'start (1,3) precedes previous end (2,2)')
        # raise if previous column in row
        self.assertRaises(ValueError, u.add_whitespace, (2,1))

    def test_backslash_continuation(self):
        # The problem is that <whitespace>\<newline> leaves no token
        u = Untokenizer()
        u.prev_row = 1
        u.prev_col =  1
        u.tokens = []
        u.add_whitespace((2, 0))
        self.assertEqual(u.tokens, ['\\\n'])
        u.prev_row = 2
        u.add_whitespace((4, 4))
        self.assertEqual(u.tokens, ['\\\n', '\\\n\\\n', '    '])
        TestRoundtrip.check_roundtrip(self, 'a\n  b\n    c\n  \\\n  c\n')

    def test_iter_compat(self):
        u = Untokenizer()
        token = (NAME, 'Hello')
        tokens = [(ENCODING, 'utf-8'), token]
        u.compat(token, iter([]))
        self.assertEqual(u.tokens, ["Hello "])
        u = Untokenizer()
        self.assertEqual(u.untokenize(iter([token])), 'Hello ')
        u = Untokenizer()
        self.assertEqual(u.untokenize(iter(tokens)), 'Hello ')
        self.assertEqual(u.encoding, 'utf-8')
        self.assertEqual(untokenize(iter(tokens)), b'Hello ')


class TestRoundtrip(TestCase):

    def check_roundtrip(self, f):
        """
        Test roundtrip for `untokenize`. `f` is an open file or a string.
        The source code in f is tokenized to both 5- and 2-tuples.
        Both sequences are converted back to source code via
        tokenize.untokenize(), and the latter tokenized again to 2-tuples.
        The test fails if the 3 pair tokenizations do not match.

        When untokenize bugs are fixed, untokenize with 5-tuples should
        reproduce code that does not contain a backslash continuation
        following spaces.  A proper test should test this.
        """
        # Get source code and original tokenizations
        if isinstance(f, str):
            code = f.encode('utf-8')
        else:
            code = f.read()
            f.close()
        readline = iter(code.splitlines(keepends=True)).__next__
        tokens5 = list(tokenize(readline))
        tokens2 = [tok[:2] for tok in tokens5]
        # Reproduce tokens2 from pairs
        bytes_from2 = untokenize(tokens2)
        readline2 = iter(bytes_from2.splitlines(keepends=True)).__next__
        tokens2_from2 = [tok[:2] for tok in tokenize(readline2)]
        self.assertEqual(tokens2_from2, tokens2)
        # Reproduce tokens2 from 5-tuples
        bytes_from5 = untokenize(tokens5)
        readline5 = iter(bytes_from5.splitlines(keepends=True)).__next__
        tokens2_from5 = [tok[:2] for tok in tokenize(readline5)]
        self.assertEqual(tokens2_from5, tokens2)

    def test_roundtrip(self):
        # There are some standard formatting practices that are easy to get right.

        self.check_roundtrip("if x == 1:\n"
                             "    print(x)\n")
        self.check_roundtrip("# This is a comment\n"
                             "# This also")

        # Some people use different formatting conventions, which makes
        # untokenize a little trickier. Note that this test involves trailing
        # whitespace after the colon. Note that we use hex escapes to make the
        # two trailing blanks apparent in the expected output.

        self.check_roundtrip("if x == 1 : \n"
                             "  print(x)\n")
        fn = support.findfile("tokenize_tests.txt")
        with open(fn, 'rb') as f:
            self.check_roundtrip(f)
        self.check_roundtrip("if x == 1:\n"
                             "    # A comment by itself.\n"
                             "    print(x) # Comment here, too.\n"
                             "    # Another comment.\n"
                             "after_if = True\n")
        self.check_roundtrip("if (x # The comments need to go in the right place\n"
                             "    == 1):\n"
                             "    print('x==1')\n")
        self.check_roundtrip("class Test: # A comment here\n"
                             "  # A comment with weird indent\n"
                             "  after_com = 5\n"
                             "  def x(m): return m*5 # a one liner\n"
                             "  def y(m): # A whitespace after the colon\n"
                             "     return y*4 # 3-space indent\n")

        # Some error-handling code
        self.check_roundtrip("try: import somemodule\n"
                             "except ImportError: # comment\n"
                             "    print('Can not import' # comment2\n)"
                             "else:   print('Loaded')\n")

    def test_continuation(self):
        # Balancing continuation
        self.check_roundtrip("a = (3,4, \n"
                             "5,6)\n"
                             "y = [3, 4,\n"
                             "5]\n"
                             "z = {'a': 5,\n"
                             "'b':15, 'c':True}\n"
                             "x = len(y) + 5 - a[\n"
                             "3] - a[2]\n"
                             "+ len(z) - z[\n"
                             "'b']\n")

    def test_backslash_continuation(self):
        # Backslash means line continuation, except for comments
        self.check_roundtrip("x=1+\\\n"
                             "1\n"
                             "# This is a comment\\\n"
                             "# This also\n")
        self.check_roundtrip("# Comment \\\n"
                             "x = 0")

    def test_string_concatenation(self):
        # Two string literals on the same line
        self.check_roundtrip("'' ''")

    def test_random_files(self):
        # Test roundtrip on random python modules.
        # pass the '-ucpu' option to process the full directory.

        import glob, random
        fn = support.findfile("tokenize_tests.txt")
        tempdir = os.path.dirname(fn) or os.curdir
        testfiles = glob.glob(os.path.join(tempdir, "test*.py"))

        # Tokenize is broken on test_pep3131.py because regular expressions are
        # broken on the obscure unicode identifiers in it. *sigh*
        # With roundtrip extended to test the 5-tuple mode of  untokenize,
        # 7 more testfiles fail.  Remove them also until the failure is diagnosed.

        testfiles.remove(os.path.join(tempdir, "test_pep3131.py"))
        for f in ('buffer', 'builtin', 'fileio', 'inspect', 'os', 'platform', 'sys'):
            testfiles.remove(os.path.join(tempdir, "test_%s.py") % f)

        if not support.is_resource_enabled("cpu"):
            testfiles = random.sample(testfiles, 10)

        for testfile in testfiles:
            with open(testfile, 'rb') as f:
                with self.subTest(file=testfile):
                    self.check_roundtrip(f)


    def roundtrip(self, code):
        if isinstance(code, str):
            code = code.encode('utf-8')
        return untokenize(tokenize(BytesIO(code).readline)).decode('utf-8')

    def test_indentation_semantics_retained(self):
        """
        Ensure that although whitespace might be mutated in a roundtrip,
        the semantic meaning of the indentation remains consistent.
        """
        code = "if False:\n\tx=3\n\tx=3\n"
        codelines = self.roundtrip(code).split('\n')
        self.assertEqual(codelines[1], codelines[2])
        self.check_roundtrip(code)


if __name__ == "__main__":
    unittest.main()