github.com/goplus/igop@v0.25.0/load/test.go

/*
 * Copyright (c) 2022 The GoPlus Authors (goplus.org). All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package load

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

// TestMain create testmain data form package
func TestMain(bp *build.Package) ([]byte, error) {
	t, err := loadTestFuncs(bp)
	if err != nil {
		return nil, err
	}
	return formatTestmain(t)
}

// TestCover not used
type TestCover struct {
	Mode     string
	Local    bool
	Pkgs     []*build.Package
	Paths    []string
	Vars     []coverInfo
	DeclVars func(*build.Package, ...string) map[string]*CoverVar
}

// isTestFunc tells whether fn has the type of a testing function. arg
// specifies the parameter type we look for: B, M or T.
func isTestFunc(fn *ast.FuncDecl, arg string) bool {
	if fn.Type.Results != nil && len(fn.Type.Results.List) > 0 ||
		fn.Type.Params.List == 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.
	// Same applies for B and T.
	if name, ok := ptr.X.(*ast.Ident); ok && name.Name == arg {
		return true
	}
	if sel, ok := ptr.X.(*ast.SelectorExpr); ok && sel.Sel.Name == arg {
		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)
}

// 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
}

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

// loadTestFuncs returns the testFuncs describing the tests that will be run.
// The returned testFuncs is always non-nil, even if an error occurred while
// processing test files.
func loadTestFuncs(bp *build.Package) (*testFuncs, error) {
	t := &testFuncs{
		Package: bp,
	}
	var err error
	for _, file := range bp.TestGoFiles {
		if lerr := t.load(filepath.Join(bp.Dir, file), "_test", &t.ImportTest, &t.NeedTest); lerr != nil && err == nil {
			err = lerr
		}
	}
	for _, file := range bp.XTestGoFiles {
		if lerr := t.load(filepath.Join(bp.Dir, file), "_xtest", &t.ImportXtest, &t.NeedXtest); lerr != nil && err == nil {
			err = lerr
		}
	}
	return t, err
}

// formatTestmain returns the content of the _testmain.go file for t.
func formatTestmain(t *testFuncs) ([]byte, error) {
	var buf bytes.Buffer
	if err := testmainTmpl.Execute(&buf, t); err != nil {
		return nil, err
	}
	return buf.Bytes(), nil
}

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

// ImportPath returns the import path of the package being tested, if it is within GOPATH.
// This is printed by the testing package when running benchmarks.
func (t *testFuncs) ImportPath() string {
	pkg := t.Package.ImportPath
	if strings.HasPrefix(pkg, "_/") {
		return ""
	}
	if pkg == "command-line-arguments" {
		return ""
	}
	return pkg
}

// 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 {
	if t.Cover == nil || t.Cover.Paths == nil {
		return ""
	}
	return " in " + strings.Join(t.Cover.Paths, ", ")
}

// 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
	Unordered bool   // output is allowed to be unordered.
}

var testFileSet = token.NewFileSet()

func (t *testFuncs) load(filename, pkg string, doImport, seen *bool) error {
	// Pass in the overlaid source if we have an overlay for this file.
	src, err := os.Open(filename)
	if err != nil {
		return err
	}
	defer src.Close()
	f, err := parser.ParseFile(testFileSet, filename, src, parser.ParseComments)
	if err != nil {
		return 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 name == "TestMain":
			if isTestFunc(n, "T") {
				t.Tests = append(t.Tests, testFunc{pkg, name, "", false})
				*doImport, *seen = true, true
				continue
			}
			err := checkTestFunc(n, "M")
			if err != nil {
				return err
			}
			if t.TestMain != nil {
				return errors.New("multiple definitions of TestMain")
			}
			t.TestMain = &testFunc{pkg, name, "", false}
			*doImport, *seen = true, true
		case isTest(name, "Test"):
			err := checkTestFunc(n, "T")
			if err != nil {
				return err
			}
			t.Tests = append(t.Tests, testFunc{pkg, name, "", false})
			*doImport, *seen = true, true
		case isTest(name, "Benchmark"):
			err := checkTestFunc(n, "B")
			if err != nil {
				return err
			}
			t.Benchmarks = append(t.Benchmarks, testFunc{pkg, name, "", false})
			*doImport, *seen = true, true
		case isTest(name, "Fuzz"):
			err := checkTestFunc(n, "F")
			if err != nil {
				return err
			}
			t.FuzzTargets = append(t.FuzzTargets, testFunc{pkg, name, "", false})
			*doImport, *seen = true, true
		}
	}
	ex := doc.Examples(f)
	sort.Slice(ex, func(i, j int) bool { return ex[i].Order < ex[j].Order })
	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, e.Unordered})
		*seen = true
	}
	return nil
}

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