gotest.go

// 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.

package test

// imported from $GOROOT/src/cmd/go/test.go

import (
	"bytes"
	"errors"
	"go/ast"
	"go/build"
	"go/doc"
	"go/parser"
	"go/scanner"
	"go/token"
	"os"
	"path/filepath"
	"sort"
	"strings"
	"text/template"
	"unicode"
	"unicode/utf8"

	"github.com/constabulary/gb"
	"github.com/constabulary/gb/debug"
)

type coverInfo struct {
	Package *gb.Package
	Vars    map[string]*CoverVar
}

// CoverVar holds the name of the generated coverage variables targeting the named file.
type CoverVar struct {
	File string // local file name
	Var  string // name of count struct
}

var cwd, _ = os.Getwd()

// shortPath returns an absolute or relative name for path, whatever is shorter.
func shortPath(path string) string {
	if rel, err := filepath.Rel(cwd, path); err == nil && len(rel) < len(path) {
		return rel
	}
	return path
}

// isTestMain tells whether fn is a TestMain(m *testing.M) function.
func isTestMain(fn *ast.FuncDecl) bool {
	if fn.Name.String() != "TestMain" ||
		fn.Type.Results != nil && len(fn.Type.Results.List) > 0 ||
		fn.Type.Params == nil ||
		len(fn.Type.Params.List) != 1 ||
		len(fn.Type.Params.List[0].Names) > 1 {
		return false
	}
	ptr, ok := fn.Type.Params.List[0].Type.(*ast.StarExpr)
	if !ok {
		return false
	}
	// We can't easily check that the type is *testing.M
	// because we don't know how testing has been imported,
	// but at least check that it's *M or *something.M.
	if name, ok := ptr.X.(*ast.Ident); ok && name.Name == "M" {
		return true
	}
	if sel, ok := ptr.X.(*ast.SelectorExpr); ok && sel.Sel.Name == "M" {
		return true
	}
	return false
}

// isTest tells whether name looks like a test (or benchmark, according to prefix).
// It is a Test (say) if there is a character after Test that is not a lower-case letter.
// We don't want TesticularCancer.
func isTest(name, prefix string) bool {
	if !strings.HasPrefix(name, prefix) {
		return false
	}
	if len(name) == len(prefix) { // "Test" is ok
		return true
	}
	rune, _ := utf8.DecodeRuneInString(name[len(prefix):])
	return !unicode.IsLower(rune)
}

// loadTestFuncs returns the testFuncs describing the tests that will be run.
func loadTestFuncs(ptest *build.Package) (*testFuncs, error) {
	t := &testFuncs{
		Package: ptest,
	}
	debug.Debugf("loadTestFuncs: %v, %v", ptest.TestGoFiles, ptest.XTestGoFiles)
	for _, file := range ptest.TestGoFiles {
		if err := t.load(filepath.Join(ptest.Dir, file), "_test", &t.ImportTest, &t.NeedTest); err != nil {
			return nil, err
		}
	}
	for _, file := range ptest.XTestGoFiles {
		if err := t.load(filepath.Join(ptest.Dir, file), "_xtest", &t.ImportXtest, &t.NeedXtest); err != nil {
			return nil, err
		}
	}
	return t, nil
}

// writeTestmain writes the _testmain.go file for t to the file named out.
func writeTestmain(out string, t *testFuncs) error {
	f, err := os.Create(out)
	if err != nil {
		return err
	}
	defer f.Close()

	if err := testmainTmpl.Execute(f, t); err != nil {
		return err
	}

	return nil
}

// expandScanner expands a scanner.List error into all the errors in the list.
// The default Error method only shows the first error.
func expandScanner(err error) error {
	// Look for parser errors.
	if err, ok := err.(scanner.ErrorList); ok {
		// Prepare error with \n before each message.
		// When printed in something like context: %v
		// this will put the leading file positions each on
		// its own line.  It will also show all the errors
		// instead of just the first, as err.Error does.
		var buf bytes.Buffer
		for _, e := range err {
			e.Pos.Filename = shortPath(e.Pos.Filename)
			buf.WriteString("\n")
			buf.WriteString(e.Error())
		}
		return errors.New(buf.String())
	}
	return err
}

type testFuncs struct {
	Tests       []testFunc
	Benchmarks  []testFunc
	Examples    []testFunc
	TestMain    *testFunc
	Package     *build.Package
	ImportTest  bool
	NeedTest    bool
	ImportXtest bool
	NeedXtest   bool
	NeedCgo     bool
	Cover       []coverInfo
}

func (t *testFuncs) CoverMode() string {
	return ""
}

func (t *testFuncs) CoverEnabled() bool {
	return false
}

// Covered returns a string describing which packages are being tested for coverage.
// If the covered package is the same as the tested package, it returns the empty string.
// Otherwise it is a comma-separated human-readable list of packages beginning with
// " in", ready for use in the coverage message.
func (t *testFuncs) Covered() string {
	return ""
}

// Tested returns the name of the package being tested.
func (t *testFuncs) Tested() string {
	return t.Package.Name
}

type testFunc struct {
	Package string // imported package name (_test or _xtest)
	Name    string // function name
	Output  string // output, for examples
}

var testFileSet = token.NewFileSet()

func (t *testFuncs) load(filename, pkg string, doImport, seen *bool) error {
	f, err := parser.ParseFile(testFileSet, filename, nil, parser.ParseComments)
	if err != nil {
		return expandScanner(err)
	}
	for _, d := range f.Decls {
		n, ok := d.(*ast.FuncDecl)
		if !ok {
			continue
		}
		if n.Recv != nil {
			continue
		}
		name := n.Name.String()
		switch {
		case isTestMain(n):
			if t.TestMain != nil {
				return errors.New("multiple definitions of TestMain")
			}
			t.TestMain = &testFunc{pkg, name, ""}
			*doImport, *seen = true, true
		case isTest(name, "Test"):
			t.Tests = append(t.Tests, testFunc{pkg, name, ""})
			*doImport, *seen = true, true
		case isTest(name, "Benchmark"):
			t.Benchmarks = append(t.Benchmarks, testFunc{pkg, name, ""})
			*doImport, *seen = true, true
		}
	}
	ex := doc.Examples(f)
	sort.Sort(byOrder(ex))
	for _, e := range ex {
		*doImport = true // import test file whether executed or not
		if e.Output == "" && !e.EmptyOutput {
			// Don't run examples with no output.
			continue
		}
		t.Examples = append(t.Examples, testFunc{pkg, "Example" + e.Name, e.Output})
		*seen = true
	}
	return nil
}

type byOrder []*doc.Example

func (x byOrder) Len() int           { return len(x) }
func (x byOrder) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
func (x byOrder) Less(i, j int) bool { return x[i].Order < x[j].Order }

var testmainTmpl = template.Must(template.New("main").Parse(`
package main

import (
{{if not .TestMain}}
	"os"
{{end}}
	"regexp"
	"testing"

{{if .ImportTest}}
	{{if .NeedTest}}_test{{else}}_{{end}} {{.Package.ImportPath | printf "%q"}}
{{end}}
{{if .ImportXtest}}
	{{if .NeedXtest}}_xtest{{else}}_{{end}} {{.Package.ImportPath | printf "%s_test" | printf "%q"}}
{{end}}
{{range $i, $p := .Cover}}
	_cover{{$i}} {{$p.Package.ImportPath | printf "%q"}}
{{end}}

{{if .NeedCgo}}
	_ "runtime/cgo"
{{end}}
)

var tests = []testing.InternalTest{
{{range .Tests}}
	{"{{.Name}}", {{.Package}}.{{.Name}}},
{{end}}
}

var benchmarks = []testing.InternalBenchmark{
{{range .Benchmarks}}
	{"{{.Name}}", {{.Package}}.{{.Name}}},
{{end}}
}

var examples = []testing.InternalExample{
{{range .Examples}}
	{"{{.Name}}", {{.Package}}.{{.Name}}, {{.Output | printf "%q"}}},
{{end}}
}

var matchPat string
var matchRe *regexp.Regexp

func matchString(pat, str string) (result bool, err error) {
	if matchRe == nil || matchPat != pat {
		matchPat = pat
		matchRe, err = regexp.Compile(matchPat)
		if err != nil {
			return
		}
	}
	return matchRe.MatchString(str), nil
}

{{if .CoverEnabled}}

// Only updated by init functions, so no need for atomicity.
var (
	coverCounters = make(map[string][]uint32)
	coverBlocks = make(map[string][]testing.CoverBlock)
)

func init() {
	{{range $i, $p := .Cover}}
	{{range $file, $cover := $p.Vars}}
	coverRegisterFile({{printf "%q" $cover.File}}, _cover{{$i}}.{{$cover.Var}}.Count[:], _cover{{$i}}.{{$cover.Var}}.Pos[:], _cover{{$i}}.{{$cover.Var}}.NumStmt[:])
	{{end}}
	{{end}}
}

func coverRegisterFile(fileName string, counter []uint32, pos []uint32, numStmts []uint16) {
	if 3*len(counter) != len(pos) || len(counter) != len(numStmts) {
		panic("coverage: mismatched sizes")
	}
	if coverCounters[fileName] != nil {
		// Already registered.
		return
	}
	coverCounters[fileName] = counter
	block := make([]testing.CoverBlock, len(counter))
	for i := range counter {
		block[i] = testing.CoverBlock{
			Line0: pos[3*i+0],
			Col0: uint16(pos[3*i+2]),
			Line1: pos[3*i+1],
			Col1: uint16(pos[3*i+2]>>16),
			Stmts: numStmts[i],
		}
	}
	coverBlocks[fileName] = block
}
{{end}}

func main() {
{{if .CoverEnabled}}
	testing.RegisterCover(testing.Cover{
		Mode: {{printf "%q" .CoverMode}},
		Counters: coverCounters,
		Blocks: coverBlocks,
		CoveredPackages: {{printf "%q" .Covered}},
	})
{{end}}
	m := testing.MainStart(matchString, tests, benchmarks, examples)
{{with .TestMain}}
	{{.Package}}.{{.Name}}(m)
{{else}}
	os.Exit(m.Run())
{{end}}
}

`))