Subversion Repositories openrisc

// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// This file implements a typechecker test harness. The packages specified
// in tests are typechecked. Error messages reported by the typechecker are
// compared against the error messages expected in the test files.
//
// Expected errors are indicated in the test files by putting a comment
// of the form /* ERROR "rx" */ immediately following an offending token.
// The harness will verify that an error matching the regular expression
// rx is reported at that source position. Consecutive comments may be
// used to indicate multiple errors for the same token position.
//
// For instance, the following test file indicates that a "not declared"
// error should be reported for the undeclared variable x:
//
//      package p
//      func f() {
//              _ = x /* ERROR "not declared" */ + 1
//      }

package types

import (
        "fmt"
        "go/ast"
        "go/parser"
        "go/scanner"
        "go/token"
        "io/ioutil"
        "os"
        "regexp"
        "testing"
)

// The test filenames do not end in .go so that they are invisible
// to gofmt since they contain comments that must not change their
// positions relative to surrounding tokens.

var tests = []struct {
        name  string
        files []string
}{
        {"test0", []string{"testdata/test0.src"}},
}

var fset = token.NewFileSet()

func getFile(filename string) (file *token.File) {
        fset.Iterate(func(f *token.File) bool {
                if f.Name() == filename {
                        file = f
                        return false // end iteration
                }
                return true
        })
        return file
}

func getPos(filename string, offset int) token.Pos {
        if f := getFile(filename); f != nil {
                return f.Pos(offset)
        }
        return token.NoPos
}

func parseFiles(t *testing.T, testname string, filenames []string) (map[string]*ast.File, error) {
        files := make(map[string]*ast.File)
        var errors scanner.ErrorList
        for _, filename := range filenames {
                if _, exists := files[filename]; exists {
                        t.Fatalf("%s: duplicate file %s", testname, filename)
                }
                file, err := parser.ParseFile(fset, filename, nil, parser.DeclarationErrors)
                if file == nil {
                        t.Fatalf("%s: could not parse file %s", testname, filename)
                }
                files[filename] = file
                if err != nil {
                        // if the parser returns a non-scanner.ErrorList error
                        // the file couldn't be read in the first place and
                        // file == nil; in that case we shouldn't reach here
                        errors = append(errors, err.(scanner.ErrorList)...)
                }

        }
        return files, errors
}

// ERROR comments must be of the form /* ERROR "rx" */ and rx is
// a regular expression that matches the expected error message.
//
var errRx = regexp.MustCompile(`^/\* *ERROR *"([^"]*)" *\*/$`)

// expectedErrors collects the regular expressions of ERROR comments found
// in files and returns them as a map of error positions to error messages.
//
func expectedErrors(t *testing.T, testname string, files map[string]*ast.File) map[token.Pos]string {
        errors := make(map[token.Pos]string)
        for filename := range files {
                src, err := ioutil.ReadFile(filename)
                if err != nil {
                        t.Fatalf("%s: could not read %s", testname, filename)
                }

                var s scanner.Scanner
                // file was parsed already - do not add it again to the file
                // set otherwise the position information returned here will
                // not match the position information collected by the parser
                s.Init(getFile(filename), src, nil, scanner.ScanComments)
                var prev token.Pos // position of last non-comment, non-semicolon token

        scanFile:
                for {
                        pos, tok, lit := s.Scan()
                        switch tok {
                        case token.EOF:
                                break scanFile
                        case token.COMMENT:
                                s := errRx.FindStringSubmatch(lit)
                                if len(s) == 2 {
                                        errors[prev] = string(s[1])
                                }
                        case token.SEMICOLON:
                                // ignore automatically inserted semicolon
                                if lit == "\n" {
                                        break
                                }
                                fallthrough
                        default:
                                prev = pos
                        }
                }
        }
        return errors
}

func eliminate(t *testing.T, expected map[token.Pos]string, errors error) {
        if errors == nil {
                return
        }
        for _, error := range errors.(scanner.ErrorList) {
                // error.Pos is a token.Position, but we want
                // a token.Pos so we can do a map lookup
                pos := getPos(error.Pos.Filename, error.Pos.Offset)
                if msg, found := expected[pos]; found {
                        // we expect a message at pos; check if it matches
                        rx, err := regexp.Compile(msg)
                        if err != nil {
                                t.Errorf("%s: %v", error.Pos, err)
                                continue
                        }
                        if match := rx.MatchString(error.Msg); !match {
                                t.Errorf("%s: %q does not match %q", error.Pos, error.Msg, msg)
                                continue
                        }
                        // we have a match - eliminate this error
                        delete(expected, pos)
                } else {
                        // To keep in mind when analyzing failed test output:
                        // If the same error position occurs multiple times in errors,
                        // this message will be triggered (because the first error at
                        // the position removes this position from the expected errors).
                        t.Errorf("%s: no (multiple?) error expected, but found: %s", error.Pos, error.Msg)
                }
        }
}

func check(t *testing.T, testname string, testfiles []string) {
        // TODO(gri) Eventually all these different phases should be
        //           subsumed into a single function call that takes
        //           a set of files and creates a fully resolved and
        //           type-checked AST.

        files, err := parseFiles(t, testname, testfiles)

        // we are expecting the following errors
        // (collect these after parsing the files so that
        // they are found in the file set)
        errors := expectedErrors(t, testname, files)

        // verify errors returned by the parser
        eliminate(t, errors, err)

        // verify errors returned after resolving identifiers
        pkg, err := ast.NewPackage(fset, files, GcImporter, Universe)
        eliminate(t, errors, err)

        // verify errors returned by the typechecker
        _, err = Check(fset, pkg)
        eliminate(t, errors, err)

        // there should be no expected errors left
        if len(errors) > 0 {
                t.Errorf("%s: %d errors not reported:", testname, len(errors))
                for pos, msg := range errors {
                        t.Errorf("%s: %s\n", fset.Position(pos), msg)
                }
        }
}

func TestCheck(t *testing.T) {
        // For easy debugging w/o changing the testing code,
        // if there is a local test file, only test that file.
        const testfile = "test.go"
        if fi, err := os.Stat(testfile); err == nil && !fi.IsDir() {
                fmt.Printf("WARNING: Testing only %s (remove it to run all tests)\n", testfile)
                check(t, testfile, []string{testfile})
                return
        }

        // Otherwise, run all the tests.
        for _, test := range tests {
                check(t, test.name, test.files)
        }
}