test.go

     1  // Copyright 2018 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  package load
     6  
     7  import (
     8  	"bytes"
     9  	"context"
    10  	"errors"
    11  	"fmt"
    12  	"go/ast"
    13  	"go/build"
    14  	"go/doc"
    15  	"go/parser"
    16  	"go/token"
    17  	"internal/lazytemplate"
    18  	"path/filepath"
    19  	"sort"
    20  	"strings"
    21  	"unicode"
    22  	"unicode/utf8"
    23  
    24  	"cmd/go/internal/fsys"
    25  	"cmd/go/internal/str"
    26  	"cmd/go/internal/trace"
    27  )
    28  
    29  var TestMainDeps = []string{
    30  	// Dependencies for testmain.
    31  	"os",
    32  	"reflect",
    33  	"testing",
    34  	"testing/internal/testdeps",
    35  }
    36  
    37  type TestCover struct {
    38  	Mode     string
    39  	Local    bool
    40  	Pkgs     []*Package
    41  	Paths    []string
    42  	Vars     []coverInfo
    43  	DeclVars func(*Package, ...string) map[string]*CoverVar
    44  }
    45  
    46  // TestPackagesFor is like TestPackagesAndErrors but it returns
    47  // an error if the test packages or their dependencies have errors.
    48  // Only test packages without errors are returned.
    49  func TestPackagesFor(ctx context.Context, opts PackageOpts, p *Package, cover *TestCover) (pmain, ptest, pxtest *Package, err error) {
    50  	pmain, ptest, pxtest = TestPackagesAndErrors(ctx, opts, p, cover)
    51  	for _, p1 := range []*Package{ptest, pxtest, pmain} {
    52  		if p1 == nil {
    53  			// pxtest may be nil
    54  			continue
    55  		}
    56  		if p1.Error != nil {
    57  			err = p1.Error
    58  			break
    59  		}
    60  		if len(p1.DepsErrors) > 0 {
    61  			perr := p1.DepsErrors[0]
    62  			err = perr
    63  			break
    64  		}
    65  	}
    66  	if pmain.Error != nil || len(pmain.DepsErrors) > 0 {
    67  		pmain = nil
    68  	}
    69  	if ptest.Error != nil || len(ptest.DepsErrors) > 0 {
    70  		ptest = nil
    71  	}
    72  	if pxtest != nil && (pxtest.Error != nil || len(pxtest.DepsErrors) > 0) {
    73  		pxtest = nil
    74  	}
    75  	return pmain, ptest, pxtest, err
    76  }
    77  
    78  // TestPackagesAndErrors returns three packages:
    79  //	- pmain, the package main corresponding to the test binary (running tests in ptest and pxtest).
    80  //	- ptest, the package p compiled with added "package p" test files.
    81  //	- pxtest, the result of compiling any "package p_test" (external) test files.
    82  //
    83  // If the package has no "package p_test" test files, pxtest will be nil.
    84  // If the non-test compilation of package p can be reused
    85  // (for example, if there are no "package p" test files and
    86  // package p need not be instrumented for coverage or any other reason),
    87  // then the returned ptest == p.
    88  //
    89  // An error is returned if the testmain source cannot be completely generated
    90  // (for example, due to a syntax error in a test file). No error will be
    91  // returned for errors loading packages, but the Error or DepsError fields
    92  // of the returned packages may be set.
    93  //
    94  // The caller is expected to have checked that len(p.TestGoFiles)+len(p.XTestGoFiles) > 0,
    95  // or else there's no point in any of this.
    96  func TestPackagesAndErrors(ctx context.Context, opts PackageOpts, p *Package, cover *TestCover) (pmain, ptest, pxtest *Package) {
    97  	ctx, span := trace.StartSpan(ctx, "load.TestPackagesAndErrors")
    98  	defer span.Done()
    99  
   100  	pre := newPreload()
   101  	defer pre.flush()
   102  	allImports := append([]string{}, p.TestImports...)
   103  	allImports = append(allImports, p.XTestImports...)
   104  	pre.preloadImports(ctx, opts, allImports, p.Internal.Build)
   105  
   106  	var ptestErr, pxtestErr *PackageError
   107  	var imports, ximports []*Package
   108  	var stk ImportStack
   109  	var testEmbed, xtestEmbed map[string][]string
   110  	stk.Push(p.ImportPath + " (test)")
   111  	rawTestImports := str.StringList(p.TestImports)
   112  	for i, path := range p.TestImports {
   113  		p1 := loadImport(ctx, opts, pre, path, p.Dir, p, &stk, p.Internal.Build.TestImportPos[path], ResolveImport)
   114  		if str.Contains(p1.Deps, p.ImportPath) || p1.ImportPath == p.ImportPath {
   115  			// Same error that loadPackage returns (via reusePackage) in pkg.go.
   116  			// Can't change that code, because that code is only for loading the
   117  			// non-test copy of a package.
   118  			ptestErr = &PackageError{
   119  				ImportStack:   importCycleStack(p1, p.ImportPath),
   120  				Err:           errors.New("import cycle not allowed in test"),
   121  				IsImportCycle: true,
   122  			}
   123  		}
   124  		p.TestImports[i] = p1.ImportPath
   125  		imports = append(imports, p1)
   126  	}
   127  	var err error
   128  	p.TestEmbedFiles, testEmbed, err = resolveEmbed(p.Dir, p.TestEmbedPatterns)
   129  	if err != nil && ptestErr == nil {
   130  		ptestErr = &PackageError{
   131  			ImportStack: stk.Copy(),
   132  			Err:         err,
   133  		}
   134  		embedErr := err.(*EmbedError)
   135  		ptestErr.setPos(p.Internal.Build.TestEmbedPatternPos[embedErr.Pattern])
   136  	}
   137  	stk.Pop()
   138  
   139  	stk.Push(p.ImportPath + "_test")
   140  	pxtestNeedsPtest := false
   141  	rawXTestImports := str.StringList(p.XTestImports)
   142  	for i, path := range p.XTestImports {
   143  		p1 := loadImport(ctx, opts, pre, path, p.Dir, p, &stk, p.Internal.Build.XTestImportPos[path], ResolveImport)
   144  		if p1.ImportPath == p.ImportPath {
   145  			pxtestNeedsPtest = true
   146  		} else {
   147  			ximports = append(ximports, p1)
   148  		}
   149  		p.XTestImports[i] = p1.ImportPath
   150  	}
   151  	p.XTestEmbedFiles, xtestEmbed, err = resolveEmbed(p.Dir, p.XTestEmbedPatterns)
   152  	if err != nil && pxtestErr == nil {
   153  		pxtestErr = &PackageError{
   154  			ImportStack: stk.Copy(),
   155  			Err:         err,
   156  		}
   157  		embedErr := err.(*EmbedError)
   158  		pxtestErr.setPos(p.Internal.Build.XTestEmbedPatternPos[embedErr.Pattern])
   159  	}
   160  	stk.Pop()
   161  
   162  	// Test package.
   163  	if len(p.TestGoFiles) > 0 || p.Name == "main" || cover != nil && cover.Local {
   164  		ptest = new(Package)
   165  		*ptest = *p
   166  		ptest.Error = ptestErr
   167  		ptest.ForTest = p.ImportPath
   168  		ptest.GoFiles = nil
   169  		ptest.GoFiles = append(ptest.GoFiles, p.GoFiles...)
   170  		ptest.GoFiles = append(ptest.GoFiles, p.TestGoFiles...)
   171  		ptest.Target = ""
   172  		// Note: The preparation of the vet config requires that common
   173  		// indexes in ptest.Imports and ptest.Internal.RawImports
   174  		// all line up (but RawImports can be shorter than the others).
   175  		// That is, for 0 ≤ i < len(RawImports),
   176  		// RawImports[i] is the import string in the program text, and
   177  		// Imports[i] is the expanded import string (vendoring applied or relative path expanded away).
   178  		// Any implicitly added imports appear in Imports and Internal.Imports
   179  		// but not RawImports (because they were not in the source code).
   180  		// We insert TestImports, imports, and rawTestImports at the start of
   181  		// these lists to preserve the alignment.
   182  		// Note that p.Internal.Imports may not be aligned with p.Imports/p.Internal.RawImports,
   183  		// but we insert at the beginning there too just for consistency.
   184  		ptest.Imports = str.StringList(p.TestImports, p.Imports)
   185  		ptest.Internal.Imports = append(imports, p.Internal.Imports...)
   186  		ptest.Internal.RawImports = str.StringList(rawTestImports, p.Internal.RawImports)
   187  		ptest.Internal.ForceLibrary = true
   188  		ptest.Internal.BuildInfo = ""
   189  		ptest.Internal.Build = new(build.Package)
   190  		*ptest.Internal.Build = *p.Internal.Build
   191  		m := map[string][]token.Position{}
   192  		for k, v := range p.Internal.Build.ImportPos {
   193  			m[k] = append(m[k], v...)
   194  		}
   195  		for k, v := range p.Internal.Build.TestImportPos {
   196  			m[k] = append(m[k], v...)
   197  		}
   198  		ptest.Internal.Build.ImportPos = m
   199  		if testEmbed == nil && len(p.Internal.Embed) > 0 {
   200  			testEmbed = map[string][]string{}
   201  		}
   202  		for k, v := range p.Internal.Embed {
   203  			testEmbed[k] = v
   204  		}
   205  		ptest.Internal.Embed = testEmbed
   206  		ptest.EmbedFiles = str.StringList(p.EmbedFiles, p.TestEmbedFiles)
   207  		ptest.Internal.OrigImportPath = p.Internal.OrigImportPath
   208  		ptest.collectDeps()
   209  	} else {
   210  		ptest = p
   211  	}
   212  
   213  	// External test package.
   214  	if len(p.XTestGoFiles) > 0 {
   215  		pxtest = &Package{
   216  			PackagePublic: PackagePublic{
   217  				Name:       p.Name + "_test",
   218  				ImportPath: p.ImportPath + "_test",
   219  				Root:       p.Root,
   220  				Dir:        p.Dir,
   221  				Goroot:     p.Goroot,
   222  				GoFiles:    p.XTestGoFiles,
   223  				Imports:    p.XTestImports,
   224  				ForTest:    p.ImportPath,
   225  				Module:     p.Module,
   226  				Error:      pxtestErr,
   227  				EmbedFiles: p.XTestEmbedFiles,
   228  			},
   229  			Internal: PackageInternal{
   230  				LocalPrefix: p.Internal.LocalPrefix,
   231  				Build: &build.Package{
   232  					ImportPos: p.Internal.Build.XTestImportPos,
   233  				},
   234  				Imports:    ximports,
   235  				RawImports: rawXTestImports,
   236  
   237  				Asmflags:       p.Internal.Asmflags,
   238  				Gcflags:        p.Internal.Gcflags,
   239  				Ldflags:        p.Internal.Ldflags,
   240  				Gccgoflags:     p.Internal.Gccgoflags,
   241  				Embed:          xtestEmbed,
   242  				OrigImportPath: p.Internal.OrigImportPath,
   243  			},
   244  		}
   245  		if pxtestNeedsPtest {
   246  			pxtest.Internal.Imports = append(pxtest.Internal.Imports, ptest)
   247  		}
   248  		pxtest.collectDeps()
   249  	}
   250  
   251  	// Build main package.
   252  	pmain = &Package{
   253  		PackagePublic: PackagePublic{
   254  			Name:       "main",
   255  			Dir:        p.Dir,
   256  			GoFiles:    []string{"_testmain.go"},
   257  			ImportPath: p.ImportPath + ".test",
   258  			Root:       p.Root,
   259  			Imports:    str.StringList(TestMainDeps),
   260  			Module:     p.Module,
   261  		},
   262  		Internal: PackageInternal{
   263  			Build:          &build.Package{Name: "main"},
   264  			BuildInfo:      p.Internal.BuildInfo,
   265  			Asmflags:       p.Internal.Asmflags,
   266  			Gcflags:        p.Internal.Gcflags,
   267  			Ldflags:        p.Internal.Ldflags,
   268  			Gccgoflags:     p.Internal.Gccgoflags,
   269  			OrigImportPath: p.Internal.OrigImportPath,
   270  		},
   271  	}
   272  
   273  	// The generated main also imports testing, regexp, and os.
   274  	// Also the linker introduces implicit dependencies reported by LinkerDeps.
   275  	stk.Push("testmain")
   276  	deps := TestMainDeps // cap==len, so safe for append
   277  	for _, d := range LinkerDeps(p) {
   278  		deps = append(deps, d)
   279  	}
   280  	for _, dep := range deps {
   281  		if dep == ptest.ImportPath {
   282  			pmain.Internal.Imports = append(pmain.Internal.Imports, ptest)
   283  		} else {
   284  			p1 := loadImport(ctx, opts, pre, dep, "", nil, &stk, nil, 0)
   285  			pmain.Internal.Imports = append(pmain.Internal.Imports, p1)
   286  		}
   287  	}
   288  	stk.Pop()
   289  
   290  	if cover != nil && cover.Pkgs != nil {
   291  		// Add imports, but avoid duplicates.
   292  		seen := map[*Package]bool{p: true, ptest: true}
   293  		for _, p1 := range pmain.Internal.Imports {
   294  			seen[p1] = true
   295  		}
   296  		for _, p1 := range cover.Pkgs {
   297  			if seen[p1] {
   298  				// Don't add duplicate imports.
   299  				continue
   300  			}
   301  			seen[p1] = true
   302  			pmain.Internal.Imports = append(pmain.Internal.Imports, p1)
   303  		}
   304  	}
   305  
   306  	allTestImports := make([]*Package, 0, len(pmain.Internal.Imports)+len(imports)+len(ximports))
   307  	allTestImports = append(allTestImports, pmain.Internal.Imports...)
   308  	allTestImports = append(allTestImports, imports...)
   309  	allTestImports = append(allTestImports, ximports...)
   310  	setToolFlags(allTestImports...)
   311  
   312  	// Do initial scan for metadata needed for writing _testmain.go
   313  	// Use that metadata to update the list of imports for package main.
   314  	// The list of imports is used by recompileForTest and by the loop
   315  	// afterward that gathers t.Cover information.
   316  	t, err := loadTestFuncs(ptest)
   317  	if err != nil && pmain.Error == nil {
   318  		pmain.setLoadPackageDataError(err, p.ImportPath, &stk, nil)
   319  	}
   320  	t.Cover = cover
   321  	if len(ptest.GoFiles)+len(ptest.CgoFiles) > 0 {
   322  		pmain.Internal.Imports = append(pmain.Internal.Imports, ptest)
   323  		pmain.Imports = append(pmain.Imports, ptest.ImportPath)
   324  		t.ImportTest = true
   325  	}
   326  	if pxtest != nil {
   327  		pmain.Internal.Imports = append(pmain.Internal.Imports, pxtest)
   328  		pmain.Imports = append(pmain.Imports, pxtest.ImportPath)
   329  		t.ImportXtest = true
   330  	}
   331  	pmain.collectDeps()
   332  
   333  	// Sort and dedup pmain.Imports.
   334  	// Only matters for go list -test output.
   335  	sort.Strings(pmain.Imports)
   336  	w := 0
   337  	for _, path := range pmain.Imports {
   338  		if w == 0 || path != pmain.Imports[w-1] {
   339  			pmain.Imports[w] = path
   340  			w++
   341  		}
   342  	}
   343  	pmain.Imports = pmain.Imports[:w]
   344  	pmain.Internal.RawImports = str.StringList(pmain.Imports)
   345  
   346  	// Replace pmain's transitive dependencies with test copies, as necessary.
   347  	recompileForTest(pmain, p, ptest, pxtest)
   348  
   349  	// Should we apply coverage analysis locally,
   350  	// only for this package and only for this test?
   351  	// Yes, if -cover is on but -coverpkg has not specified
   352  	// a list of packages for global coverage.
   353  	if cover != nil && cover.Local {
   354  		ptest.Internal.CoverMode = cover.Mode
   355  		var coverFiles []string
   356  		coverFiles = append(coverFiles, ptest.GoFiles...)
   357  		coverFiles = append(coverFiles, ptest.CgoFiles...)
   358  		ptest.Internal.CoverVars = cover.DeclVars(ptest, coverFiles...)
   359  	}
   360  
   361  	for _, cp := range pmain.Internal.Imports {
   362  		if len(cp.Internal.CoverVars) > 0 {
   363  			t.Cover.Vars = append(t.Cover.Vars, coverInfo{cp, cp.Internal.CoverVars})
   364  		}
   365  	}
   366  
   367  	data, err := formatTestmain(t)
   368  	if err != nil && pmain.Error == nil {
   369  		pmain.Error = &PackageError{Err: err}
   370  	}
   371  	// Set TestmainGo even if it is empty: the presence of a TestmainGo
   372  	// indicates that this package is, in fact, a test main.
   373  	pmain.Internal.TestmainGo = &data
   374  
   375  	return pmain, ptest, pxtest
   376  }
   377  
   378  // importCycleStack returns an import stack from p to the package whose import
   379  // path is target.
   380  func importCycleStack(p *Package, target string) []string {
   381  	// importerOf maps each import path to its importer nearest to p.
   382  	importerOf := map[string]string{p.ImportPath: ""}
   383  
   384  	// q is a breadth-first queue of packages to search for target.
   385  	// Every package added to q has a corresponding entry in pathTo.
   386  	//
   387  	// We search breadth-first for two reasons:
   388  	//
   389  	// 	1. We want to report the shortest cycle.
   390  	//
   391  	// 	2. If p contains multiple cycles, the first cycle we encounter might not
   392  	// 	   contain target. To ensure termination, we have to break all cycles
   393  	// 	   other than the first.
   394  	q := []*Package{p}
   395  
   396  	for len(q) > 0 {
   397  		p := q[0]
   398  		q = q[1:]
   399  		if path := p.ImportPath; path == target {
   400  			var stk []string
   401  			for path != "" {
   402  				stk = append(stk, path)
   403  				path = importerOf[path]
   404  			}
   405  			return stk
   406  		}
   407  		for _, dep := range p.Internal.Imports {
   408  			if _, ok := importerOf[dep.ImportPath]; !ok {
   409  				importerOf[dep.ImportPath] = p.ImportPath
   410  				q = append(q, dep)
   411  			}
   412  		}
   413  	}
   414  
   415  	panic("lost path to cycle")
   416  }
   417  
   418  // recompileForTest copies and replaces certain packages in pmain's dependency
   419  // graph. This is necessary for two reasons. First, if ptest is different than
   420  // preal, packages that import the package under test should get ptest instead
   421  // of preal. This is particularly important if pxtest depends on functionality
   422  // exposed in test sources in ptest. Second, if there is a main package
   423  // (other than pmain) anywhere, we need to set p.Internal.ForceLibrary and
   424  // clear p.Internal.BuildInfo in the test copy to prevent link conflicts.
   425  // This may happen if both -coverpkg and the command line patterns include
   426  // multiple main packages.
   427  func recompileForTest(pmain, preal, ptest, pxtest *Package) {
   428  	// The "test copy" of preal is ptest.
   429  	// For each package that depends on preal, make a "test copy"
   430  	// that depends on ptest. And so on, up the dependency tree.
   431  	testCopy := map[*Package]*Package{preal: ptest}
   432  	for _, p := range PackageList([]*Package{pmain}) {
   433  		if p == preal {
   434  			continue
   435  		}
   436  		// Copy on write.
   437  		didSplit := p == pmain || p == pxtest
   438  		split := func() {
   439  			if didSplit {
   440  				return
   441  			}
   442  			didSplit = true
   443  			if testCopy[p] != nil {
   444  				panic("recompileForTest loop")
   445  			}
   446  			p1 := new(Package)
   447  			testCopy[p] = p1
   448  			*p1 = *p
   449  			p1.ForTest = preal.ImportPath
   450  			p1.Internal.Imports = make([]*Package, len(p.Internal.Imports))
   451  			copy(p1.Internal.Imports, p.Internal.Imports)
   452  			p1.Imports = make([]string, len(p.Imports))
   453  			copy(p1.Imports, p.Imports)
   454  			p = p1
   455  			p.Target = ""
   456  			p.Internal.BuildInfo = ""
   457  			p.Internal.ForceLibrary = true
   458  		}
   459  
   460  		// Update p.Internal.Imports to use test copies.
   461  		for i, imp := range p.Internal.Imports {
   462  			if p1 := testCopy[imp]; p1 != nil && p1 != imp {
   463  				split()
   464  				p.Internal.Imports[i] = p1
   465  			}
   466  		}
   467  
   468  		// Force main packages the test imports to be built as libraries.
   469  		// Normal imports of main packages are forbidden by the package loader,
   470  		// but this can still happen if -coverpkg patterns include main packages:
   471  		// covered packages are imported by pmain. Linking multiple packages
   472  		// compiled with '-p main' causes duplicate symbol errors.
   473  		// See golang.org/issue/30907, golang.org/issue/34114.
   474  		if p.Name == "main" && p != pmain && p != ptest {
   475  			split()
   476  		}
   477  	}
   478  }
   479  
   480  // isTestFunc tells whether fn has the type of a testing function. arg
   481  // specifies the parameter type we look for: B, M or T.
   482  func isTestFunc(fn *ast.FuncDecl, arg string) bool {
   483  	if fn.Type.Results != nil && len(fn.Type.Results.List) > 0 ||
   484  		fn.Type.Params.List == nil ||
   485  		len(fn.Type.Params.List) != 1 ||
   486  		len(fn.Type.Params.List[0].Names) > 1 {
   487  		return false
   488  	}
   489  	ptr, ok := fn.Type.Params.List[0].Type.(*ast.StarExpr)
   490  	if !ok {
   491  		return false
   492  	}
   493  	// We can't easily check that the type is *testing.M
   494  	// because we don't know how testing has been imported,
   495  	// but at least check that it's *M or *something.M.
   496  	// Same applies for B and T.
   497  	if name, ok := ptr.X.(*ast.Ident); ok && name.Name == arg {
   498  		return true
   499  	}
   500  	if sel, ok := ptr.X.(*ast.SelectorExpr); ok && sel.Sel.Name == arg {
   501  		return true
   502  	}
   503  	return false
   504  }
   505  
   506  // isTest tells whether name looks like a test (or benchmark, according to prefix).
   507  // It is a Test (say) if there is a character after Test that is not a lower-case letter.
   508  // We don't want TesticularCancer.
   509  func isTest(name, prefix string) bool {
   510  	if !strings.HasPrefix(name, prefix) {
   511  		return false
   512  	}
   513  	if len(name) == len(prefix) { // "Test" is ok
   514  		return true
   515  	}
   516  	rune, _ := utf8.DecodeRuneInString(name[len(prefix):])
   517  	return !unicode.IsLower(rune)
   518  }
   519  
   520  type coverInfo struct {
   521  	Package *Package
   522  	Vars    map[string]*CoverVar
   523  }
   524  
   525  // loadTestFuncs returns the testFuncs describing the tests that will be run.
   526  // The returned testFuncs is always non-nil, even if an error occurred while
   527  // processing test files.
   528  func loadTestFuncs(ptest *Package) (*testFuncs, error) {
   529  	t := &testFuncs{
   530  		Package: ptest,
   531  	}
   532  	var err error
   533  	for _, file := range ptest.TestGoFiles {
   534  		if lerr := t.load(filepath.Join(ptest.Dir, file), "_test", &t.ImportTest, &t.NeedTest); lerr != nil && err == nil {
   535  			err = lerr
   536  		}
   537  	}
   538  	for _, file := range ptest.XTestGoFiles {
   539  		if lerr := t.load(filepath.Join(ptest.Dir, file), "_xtest", &t.ImportXtest, &t.NeedXtest); lerr != nil && err == nil {
   540  			err = lerr
   541  		}
   542  	}
   543  	return t, err
   544  }
   545  
   546  // formatTestmain returns the content of the _testmain.go file for t.
   547  func formatTestmain(t *testFuncs) ([]byte, error) {
   548  	var buf bytes.Buffer
   549  	if err := testmainTmpl.Execute(&buf, t); err != nil {
   550  		return nil, err
   551  	}
   552  	return buf.Bytes(), nil
   553  }
   554  
   555  type testFuncs struct {
   556  	Tests       []testFunc
   557  	Benchmarks  []testFunc
   558  	FuzzTargets []testFunc
   559  	Examples    []testFunc
   560  	TestMain    *testFunc
   561  	Package     *Package
   562  	ImportTest  bool
   563  	NeedTest    bool
   564  	ImportXtest bool
   565  	NeedXtest   bool
   566  	Cover       *TestCover
   567  }
   568  
   569  // ImportPath returns the import path of the package being tested, if it is within GOPATH.
   570  // This is printed by the testing package when running benchmarks.
   571  func (t *testFuncs) ImportPath() string {
   572  	pkg := t.Package.ImportPath
   573  	if strings.HasPrefix(pkg, "_/") {
   574  		return ""
   575  	}
   576  	if pkg == "command-line-arguments" {
   577  		return ""
   578  	}
   579  	return pkg
   580  }
   581  
   582  // Covered returns a string describing which packages are being tested for coverage.
   583  // If the covered package is the same as the tested package, it returns the empty string.
   584  // Otherwise it is a comma-separated human-readable list of packages beginning with
   585  // " in", ready for use in the coverage message.
   586  func (t *testFuncs) Covered() string {
   587  	if t.Cover == nil || t.Cover.Paths == nil {
   588  		return ""
   589  	}
   590  	return " in " + strings.Join(t.Cover.Paths, ", ")
   591  }
   592  
   593  // Tested returns the name of the package being tested.
   594  func (t *testFuncs) Tested() string {
   595  	return t.Package.Name
   596  }
   597  
   598  type testFunc struct {
   599  	Package   string // imported package name (_test or _xtest)
   600  	Name      string // function name
   601  	Output    string // output, for examples
   602  	Unordered bool   // output is allowed to be unordered.
   603  }
   604  
   605  var testFileSet = token.NewFileSet()
   606  
   607  func (t *testFuncs) load(filename, pkg string, doImport, seen *bool) error {
   608  	// Pass in the overlaid source if we have an overlay for this file.
   609  	src, err := fsys.Open(filename)
   610  	if err != nil {
   611  		return err
   612  	}
   613  	defer src.Close()
   614  	f, err := parser.ParseFile(testFileSet, filename, src, parser.ParseComments)
   615  	if err != nil {
   616  		return err
   617  	}
   618  	for _, d := range f.Decls {
   619  		n, ok := d.(*ast.FuncDecl)
   620  		if !ok {
   621  			continue
   622  		}
   623  		if n.Recv != nil {
   624  			continue
   625  		}
   626  		name := n.Name.String()
   627  		switch {
   628  		case name == "TestMain":
   629  			if isTestFunc(n, "T") {
   630  				t.Tests = append(t.Tests, testFunc{pkg, name, "", false})
   631  				*doImport, *seen = true, true
   632  				continue
   633  			}
   634  			err := checkTestFunc(n, "M")
   635  			if err != nil {
   636  				return err
   637  			}
   638  			if t.TestMain != nil {
   639  				return errors.New("multiple definitions of TestMain")
   640  			}
   641  			t.TestMain = &testFunc{pkg, name, "", false}
   642  			*doImport, *seen = true, true
   643  		case isTest(name, "Test"):
   644  			err := checkTestFunc(n, "T")
   645  			if err != nil {
   646  				return err
   647  			}
   648  			t.Tests = append(t.Tests, testFunc{pkg, name, "", false})
   649  			*doImport, *seen = true, true
   650  		case isTest(name, "Benchmark"):
   651  			err := checkTestFunc(n, "B")
   652  			if err != nil {
   653  				return err
   654  			}
   655  			t.Benchmarks = append(t.Benchmarks, testFunc{pkg, name, "", false})
   656  			*doImport, *seen = true, true
   657  		case isTest(name, "Fuzz"):
   658  			err := checkTestFunc(n, "F")
   659  			if err != nil {
   660  				return err
   661  			}
   662  			t.FuzzTargets = append(t.FuzzTargets, testFunc{pkg, name, "", false})
   663  			*doImport, *seen = true, true
   664  		}
   665  	}
   666  	ex := doc.Examples(f)
   667  	sort.Slice(ex, func(i, j int) bool { return ex[i].Order < ex[j].Order })
   668  	for _, e := range ex {
   669  		*doImport = true // import test file whether executed or not
   670  		if e.Output == "" && !e.EmptyOutput {
   671  			// Don't run examples with no output.
   672  			continue
   673  		}
   674  		t.Examples = append(t.Examples, testFunc{pkg, "Example" + e.Name, e.Output, e.Unordered})
   675  		*seen = true
   676  	}
   677  	return nil
   678  }
   679  
   680  func checkTestFunc(fn *ast.FuncDecl, arg string) error {
   681  	var why string
   682  	if !isTestFunc(fn, arg) {
   683  		why = fmt.Sprintf("must be: func %s(%s *testing.%s)", fn.Name.String(), strings.ToLower(arg), arg)
   684  	}
   685  	if fn.Type.TypeParams.NumFields() > 0 {
   686  		why = "test functions cannot have type parameters"
   687  	}
   688  	if why != "" {
   689  		pos := testFileSet.Position(fn.Pos())
   690  		return fmt.Errorf("%s: wrong signature for %s, %s", pos, fn.Name.String(), why)
   691  	}
   692  	return nil
   693  }
   694  
   695  var testmainTmpl = lazytemplate.New("main", `
   696  // Code generated by 'go test'. DO NOT EDIT.
   697  
   698  package main
   699  
   700  import (
   701  	"os"
   702  {{if .TestMain}}
   703  	"reflect"
   704  {{end}}
   705  	"testing"
   706  	"testing/internal/testdeps"
   707  
   708  {{if .ImportTest}}
   709  	{{if .NeedTest}}_test{{else}}_{{end}} {{.Package.ImportPath | printf "%q"}}
   710  {{end}}
   711  {{if .ImportXtest}}
   712  	{{if .NeedXtest}}_xtest{{else}}_{{end}} {{.Package.ImportPath | printf "%s_test" | printf "%q"}}
   713  {{end}}
   714  {{if .Cover}}
   715  {{range $i, $p := .Cover.Vars}}
   716  	_cover{{$i}} {{$p.Package.ImportPath | printf "%q"}}
   717  {{end}}
   718  {{end}}
   719  )
   720  
   721  var tests = []testing.InternalTest{
   722  {{range .Tests}}
   723  	{"{{.Name}}", {{.Package}}.{{.Name}}},
   724  {{end}}
   725  }
   726  
   727  var benchmarks = []testing.InternalBenchmark{
   728  {{range .Benchmarks}}
   729  	{"{{.Name}}", {{.Package}}.{{.Name}}},
   730  {{end}}
   731  }
   732  
   733  var fuzzTargets = []testing.InternalFuzzTarget{
   734  {{range .FuzzTargets}}
   735  	{"{{.Name}}", {{.Package}}.{{.Name}}},
   736  {{end}}
   737  }
   738  
   739  var examples = []testing.InternalExample{
   740  {{range .Examples}}
   741  	{"{{.Name}}", {{.Package}}.{{.Name}}, {{.Output | printf "%q"}}, {{.Unordered}}},
   742  {{end}}
   743  }
   744  
   745  func init() {
   746  	testdeps.ImportPath = {{.ImportPath | printf "%q"}}
   747  }
   748  
   749  {{if .Cover}}
   750  
   751  // Only updated by init functions, so no need for atomicity.
   752  var (
   753  	coverCounters = make(map[string][]uint32)
   754  	coverBlocks = make(map[string][]testing.CoverBlock)
   755  )
   756  
   757  func init() {
   758  	{{range $i, $p := .Cover.Vars}}
   759  	{{range $file, $cover := $p.Vars}}
   760  	coverRegisterFile({{printf "%q" $cover.File}}, _cover{{$i}}.{{$cover.Var}}.Count[:], _cover{{$i}}.{{$cover.Var}}.Pos[:], _cover{{$i}}.{{$cover.Var}}.NumStmt[:])
   761  	{{end}}
   762  	{{end}}
   763  }
   764  
   765  func coverRegisterFile(fileName string, counter []uint32, pos []uint32, numStmts []uint16) {
   766  	if 3*len(counter) != len(pos) || len(counter) != len(numStmts) {
   767  		panic("coverage: mismatched sizes")
   768  	}
   769  	if coverCounters[fileName] != nil {
   770  		// Already registered.
   771  		return
   772  	}
   773  	coverCounters[fileName] = counter
   774  	block := make([]testing.CoverBlock, len(counter))
   775  	for i := range counter {
   776  		block[i] = testing.CoverBlock{
   777  			Line0: pos[3*i+0],
   778  			Col0: uint16(pos[3*i+2]),
   779  			Line1: pos[3*i+1],
   780  			Col1: uint16(pos[3*i+2]>>16),
   781  			Stmts: numStmts[i],
   782  		}
   783  	}
   784  	coverBlocks[fileName] = block
   785  }
   786  {{end}}
   787  
   788  func main() {
   789  {{if .Cover}}
   790  	testing.RegisterCover(testing.Cover{
   791  		Mode: {{printf "%q" .Cover.Mode}},
   792  		Counters: coverCounters,
   793  		Blocks: coverBlocks,
   794  		CoveredPackages: {{printf "%q" .Covered}},
   795  	})
   796  {{end}}
   797  	m := testing.MainStart(testdeps.TestDeps{}, tests, benchmarks, fuzzTargets, examples)
   798  {{with .TestMain}}
   799  	{{.Package}}.{{.Name}}(m)
   800  	os.Exit(int(reflect.ValueOf(m).Elem().FieldByName("exitCode").Int()))
   801  {{else}}
   802  	os.Exit(m.Run())
   803  {{end}}
   804  }
   805  
   806  `)
   807
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