testenv.go

     1  // Copyright 2015 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 testenv provides information about what functionality
     6  // is available in different testing environments run by the Go team.
     7  //
     8  // It is an internal package because these details are specific
     9  // to the Go team's test setup (on build.golang.org) and not
    10  // fundamental to tests in general.
    11  package testenv
    12  
    13  import (
    14  	"bytes"
    15  	"errors"
    16  	"flag"
    17  	"fmt"
    18  	"internal/cfg"
    19  	"internal/platform"
    20  	"os"
    21  	"os/exec"
    22  	"path/filepath"
    23  	"runtime"
    24  	"strconv"
    25  	"strings"
    26  	"sync"
    27  	"testing"
    28  )
    29  
    30  // Save the original environment during init for use in checks. A test
    31  // binary may modify its environment before calling HasExec to change its
    32  // behavior (such as mimicking a command-line tool), and that modified
    33  // environment might cause environment checks to behave erratically.
    34  var origEnv = os.Environ()
    35  
    36  // Builder reports the name of the builder running this test
    37  // (for example, "linux-amd64" or "windows-386-gce").
    38  // If the test is not running on the build infrastructure,
    39  // Builder returns the empty string.
    40  func Builder() string {
    41  	return os.Getenv("GO_BUILDER_NAME")
    42  }
    43  
    44  // HasGoBuild reports whether the current system can build programs with “go build”
    45  // and then run them with os.StartProcess or exec.Command.
    46  func HasGoBuild() bool {
    47  	if os.Getenv("GO_GCFLAGS") != "" {
    48  		// It's too much work to require every caller of the go command
    49  		// to pass along "-gcflags="+os.Getenv("GO_GCFLAGS").
    50  		// For now, if $GO_GCFLAGS is set, report that we simply can't
    51  		// run go build.
    52  		return false
    53  	}
    54  
    55  	goBuildOnce.Do(func() {
    56  		// To run 'go build', we need to be able to exec a 'go' command.
    57  		// We somewhat arbitrarily choose to exec 'go tool -n compile' because that
    58  		// also confirms that cmd/go can find the compiler. (Before CL 472096,
    59  		// we sometimes ended up with cmd/go installed in the test environment
    60  		// without a cmd/compile it could use to actually build things.)
    61  		cmd := exec.Command("go", "tool", "-n", "compile")
    62  		cmd.Env = origEnv
    63  		out, err := cmd.Output()
    64  		if err != nil {
    65  			goBuildErr = fmt.Errorf("%v: %w", cmd, err)
    66  			return
    67  		}
    68  		out = bytes.TrimSpace(out)
    69  		if len(out) == 0 {
    70  			goBuildErr = fmt.Errorf("%v: no tool reported", cmd)
    71  			return
    72  		}
    73  		if _, err := exec.LookPath(string(out)); err != nil {
    74  			goBuildErr = err
    75  			return
    76  		}
    77  
    78  		if platform.MustLinkExternal(runtime.GOOS, runtime.GOARCH, false) {
    79  			// We can assume that we always have a complete Go toolchain available.
    80  			// However, this platform requires a C linker to build even pure Go
    81  			// programs, including tests. Do we have one in the test environment?
    82  			// (On Android, for example, the device running the test might not have a
    83  			// C toolchain installed.)
    84  			//
    85  			// If CC is set explicitly, assume that we do. Otherwise, use 'go env CC'
    86  			// to determine which toolchain it would use by default.
    87  			if os.Getenv("CC") == "" {
    88  				cmd := exec.Command("go", "env", "CC")
    89  				cmd.Env = origEnv
    90  				out, err := cmd.Output()
    91  				if err != nil {
    92  					goBuildErr = fmt.Errorf("%v: %w", cmd, err)
    93  					return
    94  				}
    95  				out = bytes.TrimSpace(out)
    96  				if len(out) == 0 {
    97  					goBuildErr = fmt.Errorf("%v: no CC reported", cmd)
    98  					return
    99  				}
   100  				_, goBuildErr = exec.LookPath(string(out))
   101  			}
   102  		}
   103  	})
   104  
   105  	return goBuildErr == nil
   106  }
   107  
   108  var (
   109  	goBuildOnce sync.Once
   110  	goBuildErr  error
   111  )
   112  
   113  // MustHaveGoBuild checks that the current system can build programs with “go build”
   114  // and then run them with os.StartProcess or exec.Command.
   115  // If not, MustHaveGoBuild calls t.Skip with an explanation.
   116  func MustHaveGoBuild(t testing.TB) {
   117  	if os.Getenv("GO_GCFLAGS") != "" {
   118  		t.Helper()
   119  		t.Skipf("skipping test: 'go build' not compatible with setting $GO_GCFLAGS")
   120  	}
   121  	if !HasGoBuild() {
   122  		t.Helper()
   123  		t.Skipf("skipping test: 'go build' unavailable: %v", goBuildErr)
   124  	}
   125  }
   126  
   127  // HasGoRun reports whether the current system can run programs with “go run”.
   128  func HasGoRun() bool {
   129  	// For now, having go run and having go build are the same.
   130  	return HasGoBuild()
   131  }
   132  
   133  // MustHaveGoRun checks that the current system can run programs with “go run”.
   134  // If not, MustHaveGoRun calls t.Skip with an explanation.
   135  func MustHaveGoRun(t testing.TB) {
   136  	if !HasGoRun() {
   137  		t.Skipf("skipping test: 'go run' not available on %s/%s", runtime.GOOS, runtime.GOARCH)
   138  	}
   139  }
   140  
   141  // HasParallelism reports whether the current system can execute multiple
   142  // threads in parallel.
   143  // There is a copy of this function in cmd/dist/test.go.
   144  func HasParallelism() bool {
   145  	switch runtime.GOOS {
   146  	case "js", "wasip1":
   147  		return false
   148  	}
   149  	return true
   150  }
   151  
   152  // MustHaveParallelism checks that the current system can execute multiple
   153  // threads in parallel. If not, MustHaveParallelism calls t.Skip with an explanation.
   154  func MustHaveParallelism(t testing.TB) {
   155  	if !HasParallelism() {
   156  		t.Skipf("skipping test: no parallelism available on %s/%s", runtime.GOOS, runtime.GOARCH)
   157  	}
   158  }
   159  
   160  // GoToolPath reports the path to the Go tool.
   161  // It is a convenience wrapper around GoTool.
   162  // If the tool is unavailable GoToolPath calls t.Skip.
   163  // If the tool should be available and isn't, GoToolPath calls t.Fatal.
   164  func GoToolPath(t testing.TB) string {
   165  	MustHaveGoBuild(t)
   166  	path, err := GoTool()
   167  	if err != nil {
   168  		t.Fatal(err)
   169  	}
   170  	// Add all environment variables that affect the Go command to test metadata.
   171  	// Cached test results will be invalidate when these variables change.
   172  	// See golang.org/issue/32285.
   173  	for _, envVar := range strings.Fields(cfg.KnownEnv) {
   174  		os.Getenv(envVar)
   175  	}
   176  	return path
   177  }
   178  
   179  var (
   180  	gorootOnce sync.Once
   181  	gorootPath string
   182  	gorootErr  error
   183  )
   184  
   185  func findGOROOT() (string, error) {
   186  	gorootOnce.Do(func() {
   187  		gorootPath = runtime.GOROOT()
   188  		if gorootPath != "" {
   189  			// If runtime.GOROOT() is non-empty, assume that it is valid.
   190  			//
   191  			// (It might not be: for example, the user may have explicitly set GOROOT
   192  			// to the wrong directory. But this case is
   193  			// rare, and if that happens the user can fix what they broke.)
   194  			return
   195  		}
   196  
   197  		// runtime.GOROOT doesn't know where GOROOT is (perhaps because the test
   198  		// binary was built with -trimpath).
   199  		//
   200  		// Since this is internal/testenv, we can cheat and assume that the caller
   201  		// is a test of some package in a subdirectory of GOROOT/src. ('go test'
   202  		// runs the test in the directory containing the packaged under test.) That
   203  		// means that if we start walking up the tree, we should eventually find
   204  		// GOROOT/src/go.mod, and we can report the parent directory of that.
   205  		//
   206  		// Notably, this works even if we can't run 'go env GOROOT' as a
   207  		// subprocess.
   208  
   209  		cwd, err := os.Getwd()
   210  		if err != nil {
   211  			gorootErr = fmt.Errorf("finding GOROOT: %w", err)
   212  			return
   213  		}
   214  
   215  		dir := cwd
   216  		for {
   217  			parent := filepath.Dir(dir)
   218  			if parent == dir {
   219  				// dir is either "." or only a volume name.
   220  				gorootErr = fmt.Errorf("failed to locate GOROOT/src in any parent directory")
   221  				return
   222  			}
   223  
   224  			if base := filepath.Base(dir); base != "src" {
   225  				dir = parent
   226  				continue // dir cannot be GOROOT/src if it doesn't end in "src".
   227  			}
   228  
   229  			b, err := os.ReadFile(filepath.Join(dir, "go.mod"))
   230  			if err != nil {
   231  				if os.IsNotExist(err) {
   232  					dir = parent
   233  					continue
   234  				}
   235  				gorootErr = fmt.Errorf("finding GOROOT: %w", err)
   236  				return
   237  			}
   238  			goMod := string(b)
   239  
   240  			for goMod != "" {
   241  				var line string
   242  				line, goMod, _ = strings.Cut(goMod, "\n")
   243  				fields := strings.Fields(line)
   244  				if len(fields) >= 2 && fields[0] == "module" && fields[1] == "std" {
   245  					// Found "module std", which is the module declaration in GOROOT/src!
   246  					gorootPath = parent
   247  					return
   248  				}
   249  			}
   250  		}
   251  	})
   252  
   253  	return gorootPath, gorootErr
   254  }
   255  
   256  // GOROOT reports the path to the directory containing the root of the Go
   257  // project source tree. This is normally equivalent to runtime.GOROOT, but
   258  // works even if the test binary was built with -trimpath and cannot exec
   259  // 'go env GOROOT'.
   260  //
   261  // If GOROOT cannot be found, GOROOT skips t if t is non-nil,
   262  // or panics otherwise.
   263  func GOROOT(t testing.TB) string {
   264  	path, err := findGOROOT()
   265  	if err != nil {
   266  		if t == nil {
   267  			panic(err)
   268  		}
   269  		t.Helper()
   270  		t.Skip(err)
   271  	}
   272  	return path
   273  }
   274  
   275  // GoTool reports the path to the Go tool.
   276  func GoTool() (string, error) {
   277  	if !HasGoBuild() {
   278  		return "", errors.New("platform cannot run go tool")
   279  	}
   280  	goToolOnce.Do(func() {
   281  		goToolPath, goToolErr = exec.LookPath("go")
   282  	})
   283  	return goToolPath, goToolErr
   284  }
   285  
   286  var (
   287  	goToolOnce sync.Once
   288  	goToolPath string
   289  	goToolErr  error
   290  )
   291  
   292  // HasSrc reports whether the entire source tree is available under GOROOT.
   293  func HasSrc() bool {
   294  	switch runtime.GOOS {
   295  	case "ios":
   296  		return false
   297  	}
   298  	return true
   299  }
   300  
   301  // HasExternalNetwork reports whether the current system can use
   302  // external (non-localhost) networks.
   303  func HasExternalNetwork() bool {
   304  	return !testing.Short() && runtime.GOOS != "js" && runtime.GOOS != "wasip1"
   305  }
   306  
   307  // MustHaveExternalNetwork checks that the current system can use
   308  // external (non-localhost) networks.
   309  // If not, MustHaveExternalNetwork calls t.Skip with an explanation.
   310  func MustHaveExternalNetwork(t testing.TB) {
   311  	if runtime.GOOS == "js" || runtime.GOOS == "wasip1" {
   312  		t.Helper()
   313  		t.Skipf("skipping test: no external network on %s", runtime.GOOS)
   314  	}
   315  	if testing.Short() {
   316  		t.Helper()
   317  		t.Skipf("skipping test: no external network in -short mode")
   318  	}
   319  }
   320  
   321  // HasCGO reports whether the current system can use cgo.
   322  func HasCGO() bool {
   323  	hasCgoOnce.Do(func() {
   324  		goTool, err := GoTool()
   325  		if err != nil {
   326  			return
   327  		}
   328  		cmd := exec.Command(goTool, "env", "CGO_ENABLED")
   329  		cmd.Env = origEnv
   330  		out, err := cmd.Output()
   331  		if err != nil {
   332  			panic(fmt.Sprintf("%v: %v", cmd, out))
   333  		}
   334  		hasCgo, err = strconv.ParseBool(string(bytes.TrimSpace(out)))
   335  		if err != nil {
   336  			panic(fmt.Sprintf("%v: non-boolean output %q", cmd, out))
   337  		}
   338  	})
   339  	return hasCgo
   340  }
   341  
   342  var (
   343  	hasCgoOnce sync.Once
   344  	hasCgo     bool
   345  )
   346  
   347  // MustHaveCGO calls t.Skip if cgo is not available.
   348  func MustHaveCGO(t testing.TB) {
   349  	if !HasCGO() {
   350  		t.Skipf("skipping test: no cgo")
   351  	}
   352  }
   353  
   354  // CanInternalLink reports whether the current system can link programs with
   355  // internal linking.
   356  func CanInternalLink(withCgo bool) bool {
   357  	return !platform.MustLinkExternal(runtime.GOOS, runtime.GOARCH, withCgo)
   358  }
   359  
   360  // MustInternalLink checks that the current system can link programs with internal
   361  // linking.
   362  // If not, MustInternalLink calls t.Skip with an explanation.
   363  func MustInternalLink(t testing.TB, withCgo bool) {
   364  	if !CanInternalLink(withCgo) {
   365  		if withCgo && CanInternalLink(false) {
   366  			t.Skipf("skipping test: internal linking on %s/%s is not supported with cgo", runtime.GOOS, runtime.GOARCH)
   367  		}
   368  		t.Skipf("skipping test: internal linking on %s/%s is not supported", runtime.GOOS, runtime.GOARCH)
   369  	}
   370  }
   371  
   372  // MustInternalLinkPIE checks whether the current system can link PIE binary using
   373  // internal linking.
   374  // If not, MustInternalLinkPIE calls t.Skip with an explanation.
   375  func MustInternalLinkPIE(t testing.TB) {
   376  	if !platform.InternalLinkPIESupported(runtime.GOOS, runtime.GOARCH) {
   377  		t.Skipf("skipping test: internal linking for buildmode=pie on %s/%s is not supported", runtime.GOOS, runtime.GOARCH)
   378  	}
   379  }
   380  
   381  // MustHaveBuildMode reports whether the current system can build programs in
   382  // the given build mode.
   383  // If not, MustHaveBuildMode calls t.Skip with an explanation.
   384  func MustHaveBuildMode(t testing.TB, buildmode string) {
   385  	if !platform.BuildModeSupported(runtime.Compiler, buildmode, runtime.GOOS, runtime.GOARCH) {
   386  		t.Skipf("skipping test: build mode %s on %s/%s is not supported by the %s compiler", buildmode, runtime.GOOS, runtime.GOARCH, runtime.Compiler)
   387  	}
   388  }
   389  
   390  // HasSymlink reports whether the current system can use os.Symlink.
   391  func HasSymlink() bool {
   392  	ok, _ := hasSymlink()
   393  	return ok
   394  }
   395  
   396  // MustHaveSymlink reports whether the current system can use os.Symlink.
   397  // If not, MustHaveSymlink calls t.Skip with an explanation.
   398  func MustHaveSymlink(t testing.TB) {
   399  	ok, reason := hasSymlink()
   400  	if !ok {
   401  		t.Skipf("skipping test: cannot make symlinks on %s/%s: %s", runtime.GOOS, runtime.GOARCH, reason)
   402  	}
   403  }
   404  
   405  // HasLink reports whether the current system can use os.Link.
   406  func HasLink() bool {
   407  	// From Android release M (Marshmallow), hard linking files is blocked
   408  	// and an attempt to call link() on a file will return EACCES.
   409  	// - https://code.google.com/p/android-developer-preview/issues/detail?id=3150
   410  	return runtime.GOOS != "plan9" && runtime.GOOS != "android"
   411  }
   412  
   413  // MustHaveLink reports whether the current system can use os.Link.
   414  // If not, MustHaveLink calls t.Skip with an explanation.
   415  func MustHaveLink(t testing.TB) {
   416  	if !HasLink() {
   417  		t.Skipf("skipping test: hardlinks are not supported on %s/%s", runtime.GOOS, runtime.GOARCH)
   418  	}
   419  }
   420  
   421  var flaky = flag.Bool("flaky", false, "run known-flaky tests too")
   422  
   423  func SkipFlaky(t testing.TB, issue int) {
   424  	t.Helper()
   425  	if !*flaky {
   426  		t.Skipf("skipping known flaky test without the -flaky flag; see golang.org/issue/%d", issue)
   427  	}
   428  }
   429  
   430  func SkipFlakyNet(t testing.TB) {
   431  	t.Helper()
   432  	if v, _ := strconv.ParseBool(os.Getenv("GO_BUILDER_FLAKY_NET")); v {
   433  		t.Skip("skipping test on builder known to have frequent network failures")
   434  	}
   435  }
   436  
   437  // CPUIsSlow reports whether the CPU running the test is suspected to be slow.
   438  func CPUIsSlow() bool {
   439  	switch runtime.GOARCH {
   440  	case "arm", "mips", "mipsle", "mips64", "mips64le", "wasm":
   441  		return true
   442  	}
   443  	return false
   444  }
   445  
   446  // SkipIfShortAndSlow skips t if -short is set and the CPU running the test is
   447  // suspected to be slow.
   448  //
   449  // (This is useful for CPU-intensive tests that otherwise complete quickly.)
   450  func SkipIfShortAndSlow(t testing.TB) {
   451  	if testing.Short() && CPUIsSlow() {
   452  		t.Helper()
   453  		t.Skipf("skipping test in -short mode on %s", runtime.GOARCH)
   454  	}
   455  }
   456  
   457  // SkipIfOptimizationOff skips t if optimization is disabled.
   458  func SkipIfOptimizationOff(t testing.TB) {
   459  	if OptimizationOff() {
   460  		t.Helper()
   461  		t.Skip("skipping test with optimization disabled")
   462  	}
   463  }
   464  
   465  // WriteImportcfg writes an importcfg file used by the compiler or linker to
   466  // dstPath containing entries for the file mappings in packageFiles, as well
   467  // as for the packages transitively imported by the package(s) in pkgs.
   468  //
   469  // pkgs may include any package pattern that is valid to pass to 'go list',
   470  // so it may also be a list of Go source files all in the same directory.
   471  func WriteImportcfg(t testing.TB, dstPath string, packageFiles map[string]string, pkgs ...string) {
   472  	t.Helper()
   473  
   474  	icfg := new(bytes.Buffer)
   475  	icfg.WriteString("# import config\n")
   476  	for k, v := range packageFiles {
   477  		fmt.Fprintf(icfg, "packagefile %s=%s\n", k, v)
   478  	}
   479  
   480  	if len(pkgs) > 0 {
   481  		// Use 'go list' to resolve any missing packages and rewrite the import map.
   482  		cmd := Command(t, GoToolPath(t), "list", "-export", "-deps", "-f", `{{if ne .ImportPath "command-line-arguments"}}{{if .Export}}{{.ImportPath}}={{.Export}}{{end}}{{end}}`)
   483  		cmd.Args = append(cmd.Args, pkgs...)
   484  		cmd.Stderr = new(strings.Builder)
   485  		out, err := cmd.Output()
   486  		if err != nil {
   487  			t.Fatalf("%v: %v\n%s", cmd, err, cmd.Stderr)
   488  		}
   489  
   490  		for _, line := range strings.Split(string(out), "\n") {
   491  			if line == "" {
   492  				continue
   493  			}
   494  			importPath, export, ok := strings.Cut(line, "=")
   495  			if !ok {
   496  				t.Fatalf("invalid line in output from %v:\n%s", cmd, line)
   497  			}
   498  			if packageFiles[importPath] == "" {
   499  				fmt.Fprintf(icfg, "packagefile %s=%s\n", importPath, export)
   500  			}
   501  		}
   502  	}
   503  
   504  	if err := os.WriteFile(dstPath, icfg.Bytes(), 0666); err != nil {
   505  		t.Fatal(err)
   506  	}
   507  }
   508  
   509  // SyscallIsNotSupported reports whether err may indicate that a system call is
   510  // not supported by the current platform or execution environment.
   511  func SyscallIsNotSupported(err error) bool {
   512  	return syscallIsNotSupported(err)
   513  }
   514
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