testenv.go

Documentation: internal/testenv

     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, or explicitly set GOROOT_FINAL but not GOROOT
   193  			// and hasn't moved the tree to GOROOT_FINAL yet. But those cases are
   194  			// rare, and if that happens the user can fix what they broke.)
   195  			return
   196  		}
   197  
   198  		// runtime.GOROOT doesn't know where GOROOT is (perhaps because the test
   199  		// binary was built with -trimpath, or perhaps because GOROOT_FINAL was set
   200  		// without GOROOT and the tree hasn't been moved there yet).
   201  		//
   202  		// Since this is internal/testenv, we can cheat and assume that the caller
   203  		// is a test of some package in a subdirectory of GOROOT/src. ('go test'
   204  		// runs the test in the directory containing the packaged under test.) That
   205  		// means that if we start walking up the tree, we should eventually find
   206  		// GOROOT/src/go.mod, and we can report the parent directory of that.
   207  		//
   208  		// Notably, this works even if we can't run 'go env GOROOT' as a
   209  		// subprocess.
   210  
   211  		cwd, err := os.Getwd()
   212  		if err != nil {
   213  			gorootErr = fmt.Errorf("finding GOROOT: %w", err)
   214  			return
   215  		}
   216  
   217  		dir := cwd
   218  		for {
   219  			parent := filepath.Dir(dir)
   220  			if parent == dir {
   221  				// dir is either "." or only a volume name.
   222  				gorootErr = fmt.Errorf("failed to locate GOROOT/src in any parent directory")
   223  				return
   224  			}
   225  
   226  			if base := filepath.Base(dir); base != "src" {
   227  				dir = parent
   228  				continue // dir cannot be GOROOT/src if it doesn't end in "src".
   229  			}
   230  
   231  			b, err := os.ReadFile(filepath.Join(dir, "go.mod"))
   232  			if err != nil {
   233  				if os.IsNotExist(err) {
   234  					dir = parent
   235  					continue
   236  				}
   237  				gorootErr = fmt.Errorf("finding GOROOT: %w", err)
   238  				return
   239  			}
   240  			goMod := string(b)
   241  
   242  			for goMod != "" {
   243  				var line string
   244  				line, goMod, _ = strings.Cut(goMod, "\n")
   245  				fields := strings.Fields(line)
   246  				if len(fields) >= 2 && fields[0] == "module" && fields[1] == "std" {
   247  					// Found "module std", which is the module declaration in GOROOT/src!
   248  					gorootPath = parent
   249  					return
   250  				}
   251  			}
   252  		}
   253  	})
   254  
   255  	return gorootPath, gorootErr
   256  }
   257  
   258  // GOROOT reports the path to the directory containing the root of the Go
   259  // project source tree. This is normally equivalent to runtime.GOROOT, but
   260  // works even if the test binary was built with -trimpath and cannot exec
   261  // 'go env GOROOT'.
   262  //
   263  // If GOROOT cannot be found, GOROOT skips t if t is non-nil,
   264  // or panics otherwise.
   265  func GOROOT(t testing.TB) string {
   266  	path, err := findGOROOT()
   267  	if err != nil {
   268  		if t == nil {
   269  			panic(err)
   270  		}
   271  		t.Helper()
   272  		t.Skip(err)
   273  	}
   274  	return path
   275  }
   276  
   277  // GoTool reports the path to the Go tool.
   278  func GoTool() (string, error) {
   279  	if !HasGoBuild() {
   280  		return "", errors.New("platform cannot run go tool")
   281  	}
   282  	goToolOnce.Do(func() {
   283  		goToolPath, goToolErr = exec.LookPath("go")
   284  	})
   285  	return goToolPath, goToolErr
   286  }
   287  
   288  var (
   289  	goToolOnce sync.Once
   290  	goToolPath string
   291  	goToolErr  error
   292  )
   293  
   294  // HasSrc reports whether the entire source tree is available under GOROOT.
   295  func HasSrc() bool {
   296  	switch runtime.GOOS {
   297  	case "ios":
   298  		return false
   299  	}
   300  	return true
   301  }
   302  
   303  // HasExternalNetwork reports whether the current system can use
   304  // external (non-localhost) networks.
   305  func HasExternalNetwork() bool {
   306  	return !testing.Short() && runtime.GOOS != "js" && runtime.GOOS != "wasip1"
   307  }
   308  
   309  // MustHaveExternalNetwork checks that the current system can use
   310  // external (non-localhost) networks.
   311  // If not, MustHaveExternalNetwork calls t.Skip with an explanation.
   312  func MustHaveExternalNetwork(t testing.TB) {
   313  	if runtime.GOOS == "js" || runtime.GOOS == "wasip1" {
   314  		t.Helper()
   315  		t.Skipf("skipping test: no external network on %s", runtime.GOOS)
   316  	}
   317  	if testing.Short() {
   318  		t.Helper()
   319  		t.Skipf("skipping test: no external network in -short mode")
   320  	}
   321  }
   322  
   323  // HasCGO reports whether the current system can use cgo.
   324  func HasCGO() bool {
   325  	hasCgoOnce.Do(func() {
   326  		goTool, err := GoTool()
   327  		if err != nil {
   328  			return
   329  		}
   330  		cmd := exec.Command(goTool, "env", "CGO_ENABLED")
   331  		cmd.Env = origEnv
   332  		out, err := cmd.Output()
   333  		if err != nil {
   334  			panic(fmt.Sprintf("%v: %v", cmd, out))
   335  		}
   336  		hasCgo, err = strconv.ParseBool(string(bytes.TrimSpace(out)))
   337  		if err != nil {
   338  			panic(fmt.Sprintf("%v: non-boolean output %q", cmd, out))
   339  		}
   340  	})
   341  	return hasCgo
   342  }
   343  
   344  var (
   345  	hasCgoOnce sync.Once
   346  	hasCgo     bool
   347  )
   348  
   349  // MustHaveCGO calls t.Skip if cgo is not available.
   350  func MustHaveCGO(t testing.TB) {
   351  	if !HasCGO() {
   352  		t.Skipf("skipping test: no cgo")
   353  	}
   354  }
   355  
   356  // CanInternalLink reports whether the current system can link programs with
   357  // internal linking.
   358  func CanInternalLink(withCgo bool) bool {
   359  	return !platform.MustLinkExternal(runtime.GOOS, runtime.GOARCH, withCgo)
   360  }
   361  
   362  // MustInternalLink checks that the current system can link programs with internal
   363  // linking.
   364  // If not, MustInternalLink calls t.Skip with an explanation.
   365  func MustInternalLink(t testing.TB, withCgo bool) {
   366  	if !CanInternalLink(withCgo) {
   367  		if withCgo && CanInternalLink(false) {
   368  			t.Skipf("skipping test: internal linking on %s/%s is not supported with cgo", runtime.GOOS, runtime.GOARCH)
   369  		}
   370  		t.Skipf("skipping test: internal linking on %s/%s is not supported", runtime.GOOS, runtime.GOARCH)
   371  	}
   372  }
   373  
   374  // MustHaveBuildMode reports whether the current system can build programs in
   375  // the given build mode.
   376  // If not, MustHaveBuildMode calls t.Skip with an explanation.
   377  func MustHaveBuildMode(t testing.TB, buildmode string) {
   378  	if !platform.BuildModeSupported(runtime.Compiler, buildmode, runtime.GOOS, runtime.GOARCH) {
   379  		t.Skipf("skipping test: build mode %s on %s/%s is not supported by the %s compiler", buildmode, runtime.GOOS, runtime.GOARCH, runtime.Compiler)
   380  	}
   381  }
   382  
   383  // HasSymlink reports whether the current system can use os.Symlink.
   384  func HasSymlink() bool {
   385  	ok, _ := hasSymlink()
   386  	return ok
   387  }
   388  
   389  // MustHaveSymlink reports whether the current system can use os.Symlink.
   390  // If not, MustHaveSymlink calls t.Skip with an explanation.
   391  func MustHaveSymlink(t testing.TB) {
   392  	ok, reason := hasSymlink()
   393  	if !ok {
   394  		t.Skipf("skipping test: cannot make symlinks on %s/%s: %s", runtime.GOOS, runtime.GOARCH, reason)
   395  	}
   396  }
   397  
   398  // HasLink reports whether the current system can use os.Link.
   399  func HasLink() bool {
   400  	// From Android release M (Marshmallow), hard linking files is blocked
   401  	// and an attempt to call link() on a file will return EACCES.
   402  	// - https://code.google.com/p/android-developer-preview/issues/detail?id=3150
   403  	return runtime.GOOS != "plan9" && runtime.GOOS != "android"
   404  }
   405  
   406  // MustHaveLink reports whether the current system can use os.Link.
   407  // If not, MustHaveLink calls t.Skip with an explanation.
   408  func MustHaveLink(t testing.TB) {
   409  	if !HasLink() {
   410  		t.Skipf("skipping test: hardlinks are not supported on %s/%s", runtime.GOOS, runtime.GOARCH)
   411  	}
   412  }
   413  
   414  var flaky = flag.Bool("flaky", false, "run known-flaky tests too")
   415  
   416  func SkipFlaky(t testing.TB, issue int) {
   417  	t.Helper()
   418  	if !*flaky {
   419  		t.Skipf("skipping known flaky test without the -flaky flag; see golang.org/issue/%d", issue)
   420  	}
   421  }
   422  
   423  func SkipFlakyNet(t testing.TB) {
   424  	t.Helper()
   425  	if v, _ := strconv.ParseBool(os.Getenv("GO_BUILDER_FLAKY_NET")); v {
   426  		t.Skip("skipping test on builder known to have frequent network failures")
   427  	}
   428  }
   429  
   430  // CPUIsSlow reports whether the CPU running the test is suspected to be slow.
   431  func CPUIsSlow() bool {
   432  	switch runtime.GOARCH {
   433  	case "arm", "mips", "mipsle", "mips64", "mips64le", "wasm":
   434  		return true
   435  	}
   436  	return false
   437  }
   438  
   439  // SkipIfShortAndSlow skips t if -short is set and the CPU running the test is
   440  // suspected to be slow.
   441  //
   442  // (This is useful for CPU-intensive tests that otherwise complete quickly.)
   443  func SkipIfShortAndSlow(t testing.TB) {
   444  	if testing.Short() && CPUIsSlow() {
   445  		t.Helper()
   446  		t.Skipf("skipping test in -short mode on %s", runtime.GOARCH)
   447  	}
   448  }
   449  
   450  // SkipIfOptimizationOff skips t if optimization is disabled.
   451  func SkipIfOptimizationOff(t testing.TB) {
   452  	if OptimizationOff() {
   453  		t.Helper()
   454  		t.Skip("skipping test with optimization disabled")
   455  	}
   456  }
   457  
   458  // WriteImportcfg writes an importcfg file used by the compiler or linker to
   459  // dstPath containing entries for the file mappings in packageFiles, as well
   460  // as for the packages transitively imported by the package(s) in pkgs.
   461  //
   462  // pkgs may include any package pattern that is valid to pass to 'go list',
   463  // so it may also be a list of Go source files all in the same directory.
   464  func WriteImportcfg(t testing.TB, dstPath string, packageFiles map[string]string, pkgs ...string) {
   465  	t.Helper()
   466  
   467  	icfg := new(bytes.Buffer)
   468  	icfg.WriteString("# import config\n")
   469  	for k, v := range packageFiles {
   470  		fmt.Fprintf(icfg, "packagefile %s=%s\n", k, v)
   471  	}
   472  
   473  	if len(pkgs) > 0 {
   474  		// Use 'go list' to resolve any missing packages and rewrite the import map.
   475  		cmd := Command(t, GoToolPath(t), "list", "-export", "-deps", "-f", `{{if ne .ImportPath "command-line-arguments"}}{{if .Export}}{{.ImportPath}}={{.Export}}{{end}}{{end}}`)
   476  		cmd.Args = append(cmd.Args, pkgs...)
   477  		cmd.Stderr = new(strings.Builder)
   478  		out, err := cmd.Output()
   479  		if err != nil {
   480  			t.Fatalf("%v: %v\n%s", cmd, err, cmd.Stderr)
   481  		}
   482  
   483  		for _, line := range strings.Split(string(out), "\n") {
   484  			if line == "" {
   485  				continue
   486  			}
   487  			importPath, export, ok := strings.Cut(line, "=")
   488  			if !ok {
   489  				t.Fatalf("invalid line in output from %v:\n%s", cmd, line)
   490  			}
   491  			if packageFiles[importPath] == "" {
   492  				fmt.Fprintf(icfg, "packagefile %s=%s\n", importPath, export)
   493  			}
   494  		}
   495  	}
   496  
   497  	if err := os.WriteFile(dstPath, icfg.Bytes(), 0666); err != nil {
   498  		t.Fatal(err)
   499  	}
   500  }
   501  
   502  // SyscallIsNotSupported reports whether err may indicate that a system call is
   503  // not supported by the current platform or execution environment.
   504  func SyscallIsNotSupported(err error) bool {
   505  	return syscallIsNotSupported(err)
   506  }
   507
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