libgo/go/exp/types/check_test.go

   1 // Copyright 2011 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 // This file implements a typechecker test harness. The packages specified
   6 // in tests are typechecked. Error messages reported by the typechecker are
   7 // compared against the error messages expected in the test files.
   8 //
   9 // Expected errors are indicated in the test files by putting a comment
  10 // of the form /* ERROR "rx" */ immediately following an offending token.
  11 // The harness will verify that an error matching the regular expression
  12 // rx is reported at that source position. Consecutive comments may be
  13 // used to indicate multiple errors for the same token position.
  14 //
  15 // For instance, the following test file indicates that a "not declared"
  16 // error should be reported for the undeclared variable x:
  17 //
  18 //      package p
  19 //      func f() {
  20 //              _ = x /* ERROR "not declared" */ + 1
  21 //      }
  22
  23 package types
  24
  25 import (
  26         // "fmt"
  27         "go/ast"
  28         "go/parser"
  29         "go/scanner"
  30         "go/token"
  31         "io/ioutil"
  32         // "os"
  33         "regexp"
  34         "testing"
  35 )
  36
  37 // The test filenames do not end in .go so that they are invisible
  38 // to gofmt since they contain comments that must not change their
  39 // positions relative to surrounding tokens.
  40
  41 var tests = []struct {
  42         name  string
  43         files []string
  44 }{
  45         {"test0", []string{"testdata/test0.src"}},
  46 }
  47
  48 var fset = token.NewFileSet()
  49
  50 func getFile(filename string) (file *token.File) {
  51         fset.Iterate(func(f *token.File) bool {
  52                 if f.Name() == filename {
  53                         file = f
  54                         return false // end iteration
  55                 }
  56                 return true
  57         })
  58         return file
  59 }
  60
  61 func getPos(filename string, offset int) token.Pos {
  62         if f := getFile(filename); f != nil {
  63                 return f.Pos(offset)
  64         }
  65         return token.NoPos
  66 }
  67
  68 func parseFiles(t *testing.T, testname string, filenames []string) (map[string]*ast.File, error) {
  69         files := make(map[string]*ast.File)
  70         var errors scanner.ErrorList
  71         for _, filename := range filenames {
  72                 if _, exists := files[filename]; exists {
  73                         t.Fatalf("%s: duplicate file %s", testname, filename)
  74                 }
  75                 file, err := parser.ParseFile(fset, filename, nil, parser.DeclarationErrors)
  76                 if file == nil {
  77                         t.Fatalf("%s: could not parse file %s", testname, filename)
  78                 }
  79                 files[filename] = file
  80                 if err != nil {
  81                         // if the parser returns a non-scanner.ErrorList error
  82                         // the file couldn't be read in the first place and
  83                         // file == nil; in that case we shouldn't reach here
  84                         errors = append(errors, err.(scanner.ErrorList)...)
  85                 }
  86
  87         }
  88         return files, errors
  89 }
  90
  91 // ERROR comments must be of the form /* ERROR "rx" */ and rx is
  92 // a regular expression that matches the expected error message.
  93 //
  94 var errRx = regexp.MustCompile(`^/\* *ERROR *"([^"]*)" *\*/$`)
  95
  96 // expectedErrors collects the regular expressions of ERROR comments found
  97 // in files and returns them as a map of error positions to error messages.
  98 //
  99 func expectedErrors(t *testing.T, testname string, files map[string]*ast.File) map[token.Pos]string {
 100         errors := make(map[token.Pos]string)
 101         for filename := range files {
 102                 src, err := ioutil.ReadFile(filename)
 103                 if err != nil {
 104                         t.Fatalf("%s: could not read %s", testname, filename)
 105                 }
 106
 107                 var s scanner.Scanner
 108                 // file was parsed already - do not add it again to the file
 109                 // set otherwise the position information returned here will
 110                 // not match the position information collected by the parser
 111                 s.Init(getFile(filename), src, nil, scanner.ScanComments)
 112                 var prev token.Pos // position of last non-comment, non-semicolon token
 113
 114         scanFile:
 115                 for {
 116                         pos, tok, lit := s.Scan()
 117                         switch tok {
 118                         case token.EOF:
 119                                 break scanFile
 120                         case token.COMMENT:
 121                                 s := errRx.FindStringSubmatch(lit)
 122                                 if len(s) == 2 {
 123                                         errors[prev] = string(s[1])
 124                                 }
 125                         case token.SEMICOLON:
 126                                 // ignore automatically inserted semicolon
 127                                 if lit == "\n" {
 128                                         break
 129                                 }
 130                                 fallthrough
 131                         default:
 132                                 prev = pos
 133                         }
 134                 }
 135         }
 136         return errors
 137 }
 138
 139 func eliminate(t *testing.T, expected map[token.Pos]string, errors error) {
 140         if errors == nil {
 141                 return
 142         }
 143         for _, error := range errors.(scanner.ErrorList) {
 144                 // error.Pos is a token.Position, but we want
 145                 // a token.Pos so we can do a map lookup
 146                 pos := getPos(error.Pos.Filename, error.Pos.Offset)
 147                 if msg, found := expected[pos]; found {
 148                         // we expect a message at pos; check if it matches
 149                         rx, err := regexp.Compile(msg)
 150                         if err != nil {
 151                                 t.Errorf("%s: %v", error.Pos, err)
 152                                 continue
 153                         }
 154                         if match := rx.MatchString(error.Msg); !match {
 155                                 t.Errorf("%s: %q does not match %q", error.Pos, error.Msg, msg)
 156                                 continue
 157                         }
 158                         // we have a match - eliminate this error
 159                         delete(expected, pos)
 160                 } else {
 161                         // To keep in mind when analyzing failed test output:
 162                         // If the same error position occurs multiple times in errors,
 163                         // this message will be triggered (because the first error at
 164                         // the position removes this position from the expected errors).
 165                         t.Errorf("%s: no (multiple?) error expected, but found: %s", error.Pos, error.Msg)
 166                 }
 167         }
 168 }
 169
 170 /*
 171
 172 This test doesn't work with gccgo--it can't read gccgo imports.
 173
 174 func check(t *testing.T, testname string, testfiles []string) {
 175         // TODO(gri) Eventually all these different phases should be
 176         //           subsumed into a single function call that takes
 177         //           a set of files and creates a fully resolved and
 178         //           type-checked AST.
 179
 180         files, err := parseFiles(t, testname, testfiles)
 181
 182         // we are expecting the following errors
 183         // (collect these after parsing the files so that
 184         // they are found in the file set)
 185         errors := expectedErrors(t, testname, files)
 186
 187         // verify errors returned by the parser
 188         eliminate(t, errors, err)
 189
 190         // verify errors returned after resolving identifiers
 191         pkg, err := ast.NewPackage(fset, files, GcImport, Universe)
 192         eliminate(t, errors, err)
 193
 194         // verify errors returned by the typechecker
 195         _, err = Check(fset, pkg)
 196         eliminate(t, errors, err)
 197
 198         // there should be no expected errors left
 199         if len(errors) > 0 {
 200                 t.Errorf("%s: %d errors not reported:", testname, len(errors))
 201                 for pos, msg := range errors {
 202                         t.Errorf("%s: %s\n", fset.Position(pos), msg)
 203                 }
 204         }
 205 }
 206
 207 func TestCheck(t *testing.T) {
 208         // For easy debugging w/o changing the testing code,
 209         // if there is a local test file, only test that file.
 210         const testfile = "testdata/test.go"
 211         if fi, err := os.Stat(testfile); err == nil && !fi.IsDir() {
 212                 fmt.Printf("WARNING: Testing only %s (remove it to run all tests)\n", testfile)
 213                 check(t, testfile, []string{testfile})
 214                 return
 215         }
 216
 217         // Otherwise, run all the tests.
 218         for _, test := range tests {
 219                 check(t, test.name, test.files)
 220         }
 221 }
 222
 223 */