testyacc.py

# testyacc.py

import unittest
try:
    import StringIO
except ImportError:
    import io as StringIO

import sys
import os
import warnings
import re

sys.path.insert(0,"..")
sys.tracebacklimit = 0

import ply.yacc
import imp

def make_pymodule_path(filename):
    path = os.path.dirname(filename)
    file = os.path.basename(filename)
    mod, ext = os.path.splitext(file)

    if sys.hexversion >= 0x3020000:
        modname = mod+"."+imp.get_tag()+ext
        fullpath = os.path.join(path,'__pycache__',modname)
    else:
        fullpath = filename
    return fullpath

def pymodule_out_exists(filename):
    return os.path.exists(make_pymodule_path(filename))

def pymodule_out_remove(filename):
    os.remove(make_pymodule_path(filename))

# Old implementation (not safe for Python 3.3)
def check_expected(result,expected):
    resultlines = []
    for line in result.splitlines():
        if line.startswith("WARNING: "):
            line = line[9:]
        elif line.startswith("ERROR: "):
            line = line[7:]
        resultlines.append(line)

    expectedlines = expected.splitlines()
    if len(resultlines) != len(expectedlines):
        return False
    for rline,eline in zip(resultlines,expectedlines):
        if not rline.endswith(eline):
            return False
    return True

# Check the output to see if it contains all of a set of expected output lines.
# This alternate implementation looks weird, but is needed to properly handle
# some variations in error message order that occurs due to dict hash table
# randomization that was introduced in Python 3.3
def check_expected(result, expected):
    # Normalize 'state n' text to account for randomization effects in Python 3.3
    expected = re.sub(r' state \d+', 'state <n>', expected)
    result = re.sub(r' state \d+', 'state <n>', result)

    resultlines = set()
    for line in result.splitlines():
        if line.startswith("WARNING: "):
            line = line[9:]
        elif line.startswith("ERROR: "):
            line = line[7:]
        resultlines.add(line)

    # Selectively remove expected lines from the output
    for eline in expected.splitlines():
        resultlines = set(line for line in resultlines if not line.endswith(eline))

    # Return True if no result lines remain
    return not bool(resultlines)

def run_import(module):
    code = "import "+module
    exec(code)
    del sys.modules[module]
    
# Tests related to errors and warnings when building parsers
class YaccErrorWarningTests(unittest.TestCase):
    def setUp(self):
        sys.stderr = StringIO.StringIO()
        sys.stdout = StringIO.StringIO()
        try:
            os.remove("parsetab.py")
            pymodule_out_remove("parsetab.pyc")
        except OSError:
            pass
        
        if sys.hexversion >= 0x3020000:
            warnings.filterwarnings('ignore',category=ResourceWarning)

    def tearDown(self):
        sys.stderr = sys.__stderr__
        sys.stdout = sys.__stdout__
    def test_yacc_badargs(self):
        self.assertRaises(ply.yacc.YaccError,run_import,"yacc_badargs")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "yacc_badargs.py:23: Rule 'p_statement_assign' has too many arguments\n"
                                    "yacc_badargs.py:27: Rule 'p_statement_expr' requires an argument\n"
                                    ))        
    def test_yacc_badid(self):
        self.assertRaises(ply.yacc.YaccError,run_import,"yacc_badid")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "yacc_badid.py:32: Illegal name 'bad&rule' in rule 'statement'\n"
                                    "yacc_badid.py:36: Illegal rule name 'bad&rule'\n"
                                    ))

    def test_yacc_badprec(self):
        try:
            run_import("yacc_badprec")
        except ply.yacc.YaccError:
            result = sys.stderr.getvalue()
            self.assert_(check_expected(result,
                                        "precedence must be a list or tuple\n"
                                        ))
    def test_yacc_badprec2(self):
        self.assertRaises(ply.yacc.YaccError,run_import,"yacc_badprec2")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "Bad precedence table\n"
                                    ))

    def test_yacc_badprec3(self):
        run_import("yacc_badprec3")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "Precedence already specified for terminal 'MINUS'\n"
                                    "Generating LALR tables\n"

                                    ))
        
    def test_yacc_badrule(self):
        self.assertRaises(ply.yacc.YaccError,run_import,"yacc_badrule")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "yacc_badrule.py:24: Syntax error. Expected ':'\n"
                                    "yacc_badrule.py:28: Syntax error in rule 'statement'\n"
                                    "yacc_badrule.py:33: Syntax error. Expected ':'\n"
                                    "yacc_badrule.py:42: Syntax error. Expected ':'\n"
                                    ))

    def test_yacc_badtok(self):
        try:
            run_import("yacc_badtok")
        except ply.yacc.YaccError:
            result = sys.stderr.getvalue()
            self.assert_(check_expected(result,
                                        "tokens must be a list or tuple\n"))

    def test_yacc_dup(self):
        run_import("yacc_dup")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "yacc_dup.py:27: Function p_statement redefined. Previously defined on line 23\n"
                                    "Token 'EQUALS' defined, but not used\n"
                                    "There is 1 unused token\n"
                                    "Generating LALR tables\n"

                                    ))
    def test_yacc_error1(self):
        try:
            run_import("yacc_error1")
        except ply.yacc.YaccError:
            result = sys.stderr.getvalue()
            self.assert_(check_expected(result,
                                        "yacc_error1.py:61: p_error() requires 1 argument\n"))

    def test_yacc_error2(self):
        try:
            run_import("yacc_error2")
        except ply.yacc.YaccError:
            result = sys.stderr.getvalue()
            self.assert_(check_expected(result,
                                        "yacc_error2.py:61: p_error() requires 1 argument\n"))

    def test_yacc_error3(self):
        try:
            run_import("yacc_error3")
        except ply.yacc.YaccError:
            e = sys.exc_info()[1]
            result = sys.stderr.getvalue()
            self.assert_(check_expected(result,
                                        "'p_error' defined, but is not a function or method\n"))
            
    def test_yacc_error4(self):
        self.assertRaises(ply.yacc.YaccError,run_import,"yacc_error4")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "yacc_error4.py:62: Illegal rule name 'error'. Already defined as a token\n"
                                    ))


    def test_yacc_error5(self):
        run_import("yacc_error5")
        result = sys.stdout.getvalue()
        self.assert_(check_expected(result,
                                    "Group at 3:10 to 3:12\n"
                                    "Syntax error at 'b'\n"
                                    "Syntax error at 4:18 to 4:22\n"
                                    "Assignment Error at 2:5 to 5:33\n"
            ))

    def test_yacc_error6(self):
        run_import("yacc_error6")
        result = sys.stdout.getvalue()
        self.assert_(check_expected(result,
                                    "a=7\n"
                                    "Line 3: Syntax error at '*'\n"
                                    "c=21\n"
            ))

    def test_yacc_error7(self):
        run_import("yacc_error7")
        result = sys.stdout.getvalue()
        self.assert_(check_expected(result,
                                    "a=7\n"
                                    "Line 3: Syntax error at '*'\n"
                                    "c=21\n"
            ))

    def test_yacc_inf(self):
        self.assertRaises(ply.yacc.YaccError,run_import,"yacc_inf")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "Token 'NUMBER' defined, but not used\n"
                                    "There is 1 unused token\n"
                                    "Infinite recursion detected for symbol 'statement'\n"
                                    "Infinite recursion detected for symbol 'expression'\n"
                                    ))
    def test_yacc_literal(self):
        self.assertRaises(ply.yacc.YaccError,run_import,"yacc_literal")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "yacc_literal.py:36: Literal token '**' in rule 'expression' may only be a single character\n"
                                    ))
    def test_yacc_misplaced(self):
        self.assertRaises(ply.yacc.YaccError,run_import,"yacc_misplaced")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "yacc_misplaced.py:32: Misplaced '|'\n"
                                    ))

    def test_yacc_missing1(self):
        self.assertRaises(ply.yacc.YaccError,run_import,"yacc_missing1")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "yacc_missing1.py:24: Symbol 'location' used, but not defined as a token or a rule\n"
                                    ))

    def test_yacc_nested(self):
        run_import("yacc_nested")
        result = sys.stdout.getvalue()
        self.assert_(check_expected(result,
                                    "A\n"
                                    "A\n"
                                    "A\n",
                                    ))

    def test_yacc_nodoc(self):
        run_import("yacc_nodoc")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "yacc_nodoc.py:27: No documentation string specified in function 'p_statement_expr' (ignored)\n"
                                    "Generating LALR tables\n"
                                    ))

    def test_yacc_noerror(self):
        run_import("yacc_noerror")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "no p_error() function is defined\n"
                                    "Generating LALR tables\n"
                                    ))

    def test_yacc_nop(self):
        run_import("yacc_nop")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "yacc_nop.py:27: Possible grammar rule 'statement_expr' defined without p_ prefix\n"
                                    "Generating LALR tables\n"
                                    ))

    def test_yacc_notfunc(self):
        run_import("yacc_notfunc")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "'p_statement_assign' not defined as a function\n"
                                    "Token 'EQUALS' defined, but not used\n"
                                    "There is 1 unused token\n"
                                    "Generating LALR tables\n"
                                    ))
    def test_yacc_notok(self):
        try:
            run_import("yacc_notok")
        except ply.yacc.YaccError:
            result = sys.stderr.getvalue()
            self.assert_(check_expected(result,
                                        "No token list is defined\n"))

    def test_yacc_rr(self):
        run_import("yacc_rr")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "Generating LALR tables\n"
                                    "1 reduce/reduce conflict\n"
                                    "reduce/reduce conflict in state 15 resolved using rule (statement -> NAME EQUALS NUMBER)\n"
                                    "rejected rule (expression -> NUMBER) in state 15\n"

                                    ))

    def test_yacc_rr_unused(self):
        run_import("yacc_rr_unused")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "no p_error() function is defined\n"
                                    "Generating LALR tables\n"
                                    "3 reduce/reduce conflicts\n"
                                    "reduce/reduce conflict in state 1 resolved using rule (rule3 -> A)\n"
                                    "rejected rule (rule4 -> A) in state 1\n"
                                    "reduce/reduce conflict in state 1 resolved using rule (rule3 -> A)\n"
                                    "rejected rule (rule5 -> A) in state 1\n"
                                    "reduce/reduce conflict in state 1 resolved using rule (rule4 -> A)\n"
                                    "rejected rule (rule5 -> A) in state 1\n"
                                    "Rule (rule5 -> A) is never reduced\n"
                                    ))

    def test_yacc_simple(self):
        run_import("yacc_simple")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "Generating LALR tables\n"
                                    ))

    def test_yacc_sr(self):
        run_import("yacc_sr")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "Generating LALR tables\n"
                                    "20 shift/reduce conflicts\n"
                                    ))

    def test_yacc_term1(self):
        self.assertRaises(ply.yacc.YaccError,run_import,"yacc_term1")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "yacc_term1.py:24: Illegal rule name 'NUMBER'. Already defined as a token\n"
                                    ))

    def test_yacc_unicode_literals(self):
        run_import("yacc_unicode_literals")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "Generating LALR tables\n"
                                    ))

    def test_yacc_unused(self):
        self.assertRaises(ply.yacc.YaccError,run_import,"yacc_unused")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "yacc_unused.py:62: Symbol 'COMMA' used, but not defined as a token or a rule\n"
                                    "Symbol 'COMMA' is unreachable\n"
                                    "Symbol 'exprlist' is unreachable\n"
                                    ))
    def test_yacc_unused_rule(self):
        run_import("yacc_unused_rule")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "yacc_unused_rule.py:62: Rule 'integer' defined, but not used\n"
                                    "There is 1 unused rule\n"
                                    "Symbol 'integer' is unreachable\n"
                                    "Generating LALR tables\n"
                                    ))

    def test_yacc_uprec(self):
        self.assertRaises(ply.yacc.YaccError,run_import,"yacc_uprec")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "yacc_uprec.py:37: Nothing known about the precedence of 'UMINUS'\n"
                                    ))

    def test_yacc_uprec2(self):
        self.assertRaises(ply.yacc.YaccError,run_import,"yacc_uprec2")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "yacc_uprec2.py:37: Syntax error. Nothing follows %prec\n"
                                    ))

    def test_yacc_prec1(self):
        self.assertRaises(ply.yacc.YaccError,run_import,"yacc_prec1")
        result = sys.stderr.getvalue()
        self.assert_(check_expected(result,
                                    "Precedence rule 'left' defined for unknown symbol '+'\n"
                                    "Precedence rule 'left' defined for unknown symbol '*'\n"
                                    "Precedence rule 'left' defined for unknown symbol '-'\n"
                                    "Precedence rule 'left' defined for unknown symbol '/'\n"
                                    ))

unittest.main()