error_test.go

Documentation: cuelang.org/go/cue/parser

     1  // Copyright 2018 The CUE Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // This file implements a parser test harness. The files in the testdata
    16  // directory are parsed and the errors reported are compared against the
    17  // error messages expected in the test files. The test files must end in
    18  // .src rather than .go so that they are not disturbed by gofmt runs.
    19  //
    20  // Expected errors are indicated in the test files by putting a comment
    21  // of the form /* ERROR "rx" */ immediately following an offending
    22  // The harness will verify that an error matching the regular expression
    23  // rx is reported at that source position.
    24  //
    25  // For instance, the following test file indicates that a "not declared"
    26  // error should be reported for the undeclared variable x:
    27  //
    28  //	package p
    29  //	{
    30  //		a = x /* ERROR "not declared" */ + 1
    31  //	}
    32  
    33  package parser
    34  
    35  import (
    36  	"regexp"
    37  	"testing"
    38  
    39  	"cuelang.org/go/cue/errors"
    40  	"cuelang.org/go/cue/scanner"
    41  	"cuelang.org/go/cue/token"
    42  	"cuelang.org/go/internal/source"
    43  )
    44  
    45  func getPos(f *token.File, offset int) token.Pos {
    46  	if f != nil {
    47  		return f.Pos(offset, 0)
    48  	}
    49  	return token.NoPos
    50  }
    51  
    52  // ERROR comments must be of the form /* ERROR "rx" */ and rx is
    53  // a regular expression that matches the expected error message.
    54  // The special form /* ERROR HERE "rx" */ must be used for error
    55  // messages that appear immediately after a token, rather than at
    56  // a token's position.
    57  var errRx = regexp.MustCompile(`^/\* *ERROR *(HERE)? *"([^"]*)" *\*/$`)
    58  
    59  // expectedErrors collects the regular expressions of ERROR comments found
    60  // in files and returns them as a map of error positions to error messages.
    61  func expectedErrors(t *testing.T, file *token.File, src []byte) map[token.Pos]string {
    62  	errors := make(map[token.Pos]string)
    63  
    64  	var s scanner.Scanner
    65  	// file was parsed already - do not add it again to the file
    66  	// set otherwise the position information returned here will
    67  	// not match the position information collected by the parser
    68  	// file := token.NewFile(filename, -1, len(src))
    69  	s.Init(file, src, nil, scanner.ScanComments)
    70  	var prev token.Pos // position of last non-comment, non-semicolon token
    71  	var here token.Pos // position immediately after the token at position prev
    72  
    73  	for {
    74  		pos, tok, lit := s.Scan()
    75  		pos = pos.WithRel(0)
    76  		switch tok {
    77  		case token.EOF:
    78  			return errors
    79  		case token.COMMENT:
    80  			s := errRx.FindStringSubmatch(lit)
    81  			if len(s) == 3 {
    82  				pos := prev
    83  				if s[1] == "HERE" {
    84  					pos = here
    85  				}
    86  				errors[pos] = string(s[2])
    87  			}
    88  		default:
    89  			prev = pos
    90  			var l int // token length
    91  			if tok.IsLiteral() {
    92  				l = len(lit)
    93  			} else {
    94  				l = len(tok.String())
    95  			}
    96  			here = prev.Add(l)
    97  		}
    98  	}
    99  }
   100  
   101  // compareErrors compares the map of expected error messages with the list
   102  // of found errors and reports discrepancies.
   103  func compareErrors(t *testing.T, file *token.File, expected map[token.Pos]string, found []errors.Error) {
   104  	t.Helper()
   105  	for _, error := range found {
   106  		// error.Pos is a Position, but we want
   107  		// a Pos so we can do a map lookup
   108  		ePos := error.Position()
   109  		eMsg := error.Error()
   110  		pos := getPos(file, ePos.Offset()).WithRel(0)
   111  		if msg, found := expected[pos]; found {
   112  			// we expect a message at pos; check if it matches
   113  			rx, err := regexp.Compile(msg)
   114  			if err != nil {
   115  				t.Errorf("%s: %v", ePos, err)
   116  				continue
   117  			}
   118  			if match := rx.MatchString(eMsg); !match {
   119  				t.Errorf("%s: %q does not match %q", ePos, eMsg, msg)
   120  				continue
   121  			}
   122  			// we have a match - eliminate this error
   123  			delete(expected, pos)
   124  		} else {
   125  			// To keep in mind when analyzing failed test output:
   126  			// If the same error position occurs multiple times in errors,
   127  			// this message will be triggered (because the first error at
   128  			// the position removes this position from the expected errors).
   129  			t.Errorf("%s: unexpected error: -%q-", ePos, eMsg)
   130  		}
   131  	}
   132  
   133  	// there should be no expected errors left
   134  	if len(expected) > 0 {
   135  		t.Errorf("%d errors not reported:", len(expected))
   136  		for pos, msg := range expected {
   137  			t.Errorf("%s: -%q-\n", pos, msg)
   138  		}
   139  	}
   140  }
   141  
   142  func checkErrors(t *testing.T, filename string, input interface{}) {
   143  	t.Helper()
   144  	src, err := source.Read(filename, input)
   145  	if err != nil {
   146  		t.Error(err)
   147  		return
   148  	}
   149  
   150  	f, err := ParseFile(filename, src, DeclarationErrors, AllErrors)
   151  	file := f.Pos().File()
   152  	found := errors.Errors(err)
   153  
   154  	// we are expecting the following errors
   155  	// (collect these after parsing a file so that it is found in the file set)
   156  	if file == nil {
   157  		t.Fatal("no token.File for ast.File")
   158  	}
   159  	expected := expectedErrors(t, file, src)
   160  
   161  	// verify errors returned by the parser
   162  	compareErrors(t, file, expected, found)
   163  }
   164  
   165  func TestFuzz(t *testing.T) {
   166  	testCases := []string{
   167  		"(({\"\\(0)\"(",
   168  		"{{\"\\(0\xbf\"(",
   169  		"a:y for x n{b:\"\"(\"\\(" +
   170  			"\"\"\\\"(",
   171  	}
   172  	for _, tc := range testCases {
   173  		t.Run("", func(t *testing.T) {
   174  			_, _ = ParseFile("go-fuzz", []byte(tc))
   175  		})
   176  	}
   177  }
   178
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