internal/testenv: add MustHaveSource, rm HasSrc

All the users of HasSrc call t.Skip anyway, so let's move it to testenv.

Fix go/build to use MustHaveSource rather than MustHaveGoBuild where
appropriate.

Change-Id: I052bf96fd5a5780c1930da5b3a52b7a8dbebea46
Reviewed-on: https://go-review.googlesource.com/c/go/+/612057
Reviewed-by: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Tim King <taking@google.com>
Auto-Submit: Tim King <taking@google.com>

src/compress/gzip/issue14937_test.go

@@ -30,9 +30,7 @@ func TestGZIPFilesHaveZeroMTimes(t *testing.T) {
 	if testenv.Builder() == "" {
 		t.Skip("skipping test on non-builder")
 	}
-	if !testenv.HasSrc() {
+	testenv.MustHaveSource(t)
-		t.Skip("skipping; no GOROOT available")
-	}
 
 	goroot, err := filepath.EvalSymlinks(runtime.GOROOT())
 	if err != nil {

src/go/build/build_test.go

@@ -496,7 +496,7 @@ func TestShellSafety(t *testing.T) {
 // Want to get a "cannot find package" error when directory for package does not exist.
 // There should be valid partial information in the returned non-nil *Package.
 func TestImportDirNotExist(t *testing.T) {
-	testenv.MustHaveGoBuild(t) // really must just have source
+	testenv.MustHaveGoBuild(t) // Need 'go list' internally.
 	ctxt := Default
 
 	emptyDir := t.TempDir()
@@ -550,7 +550,7 @@ func TestImportDirNotExist(t *testing.T) {
 }
 
 func TestImportVendor(t *testing.T) {
-	testenv.MustHaveGoBuild(t) // really must just have source
+	testenv.MustHaveSource(t)
 
 	t.Setenv("GO111MODULE", "off")
 
@@ -571,7 +571,7 @@ func TestImportVendor(t *testing.T) {
 }
 
 func BenchmarkImportVendor(b *testing.B) {
-	testenv.MustHaveGoBuild(b) // really must just have source
+	testenv.MustHaveSource(b)
 
 	b.Setenv("GO111MODULE", "off")
 
@@ -592,7 +592,7 @@ func BenchmarkImportVendor(b *testing.B) {
 }
 
 func TestImportVendorFailure(t *testing.T) {
-	testenv.MustHaveGoBuild(t) // really must just have source
+	testenv.MustHaveSource(t)
 
 	t.Setenv("GO111MODULE", "off")
 
@@ -614,7 +614,7 @@ func TestImportVendorFailure(t *testing.T) {
 }
 
 func TestImportVendorParentFailure(t *testing.T) {
-	testenv.MustHaveGoBuild(t) // really must just have source
+	testenv.MustHaveSource(t)
 
 	t.Setenv("GO111MODULE", "off")
 

src/go/build/deps_test.go

@@ -16,7 +16,6 @@ import (
 	"io/fs"
 	"os"
 	"path/filepath"
-	"runtime"
 	"slices"
 	"strings"
 	"testing"
@@ -751,11 +750,7 @@ func listStdPkgs(goroot string) ([]string, error) {
 }
 
 func TestDependencies(t *testing.T) {
-	if !testenv.HasSrc() {
+	testenv.MustHaveSource(t)
-		// Tests run in a limited file system and we do not
-		// provide access to every source file.
-		t.Skipf("skipping on %s/%s, missing full GOROOT", runtime.GOOS, runtime.GOARCH)
-	}
 
 	ctxt := Default
 	all, err := listStdPkgs(ctxt.GOROOT)
@@ -859,9 +854,7 @@ func depsPolicy(t *testing.T) *dag.Graph {
 // TestStdlibLowercase tests that all standard library package names are
 // lowercase. See Issue 40065.
 func TestStdlibLowercase(t *testing.T) {
-	if !testenv.HasSrc() {
+	testenv.MustHaveSource(t)
-		t.Skipf("skipping on %s/%s, missing full GOROOT", runtime.GOOS, runtime.GOARCH)
-	}
 
 	ctxt := Default
 	all, err := listStdPkgs(ctxt.GOROOT)

src/go/internal/srcimporter/srcimporter_test.go

@@ -83,9 +83,7 @@ func walkDir(t *testing.T, path string, endTime time.Time) (int, bool) {
 }
 
 func TestImportStdLib(t *testing.T) {
-	if !testenv.HasSrc() {
+	testenv.MustHaveSource(t)
-		t.Skip("no source code available")
-	}
 
 	if testing.Short() && testenv.Builder() == "" {
 		t.Skip("skipping in -short mode")
@@ -109,9 +107,7 @@ var importedObjectTests = []struct {
 }
 
 func TestImportedTypes(t *testing.T) {
-	if !testenv.HasSrc() {
+	testenv.MustHaveSource(t)
-		t.Skip("no source code available")
-	}
 
 	for _, test := range importedObjectTests {
 		i := strings.LastIndex(test.name, ".")
@@ -179,9 +175,7 @@ func verifyInterfaceMethodRecvs(t *testing.T, named *types.Named, level int) {
 }
 
 func TestReimport(t *testing.T) {
-	if !testenv.HasSrc() {
+	testenv.MustHaveSource(t)
-		t.Skip("no source code available")
-	}
 
 	// Reimporting a partially imported (incomplete) package is not supported (see issue #19337).
 	// Make sure we recognize the situation and report an error.
@@ -195,9 +189,7 @@ func TestReimport(t *testing.T) {
 }
 
 func TestIssue20855(t *testing.T) {
-	if !testenv.HasSrc() {
+	testenv.MustHaveSource(t)
-		t.Skip("no source code available")
-	}
 
 	pkg, err := importer.ImportFrom("go/internal/srcimporter/testdata/issue20855", ".", 0)
 	if err == nil || !strings.Contains(err.Error(), "missing function body") {
@@ -209,9 +201,7 @@ func TestIssue20855(t *testing.T) {
 }
 
 func testImportPath(t *testing.T, pkgPath string) {
-	if !testenv.HasSrc() {
+	testenv.MustHaveSource(t)
-		t.Skip("no source code available")
-	}
 
 	pkgName := path.Base(pkgPath)
 

src/internal/testenv/testenv.go

@@ -268,13 +268,14 @@ var goTool = sync.OnceValues(func() (string, error) {
 	return exec.LookPath("go")
 })
 
-// HasSrc reports whether the entire source tree is available under GOROOT.
+// MustHaveSource checks that the entire source tree is available under GOROOT.
-func HasSrc() bool {
+// If not, it calls t.Skip with an explanation.
+func MustHaveSource(t testing.TB) {
 	switch runtime.GOOS {
 	case "ios":
-		return false
+		t.Helper()
+		t.Skip("skipping test: no source tree on " + runtime.GOOS)
 	}
-	return true
 }
 
 // HasExternalNetwork reports whether the current system can use

src/net/http/http_test.go

@@ -151,9 +151,7 @@ var forbiddenStringsFunctions = map[string]bool{
 // strings and bytes package functions. HTTP is mostly ASCII based, and doing
 // Unicode-aware case folding or space stripping can introduce vulnerabilities.
 func TestNoUnicodeStrings(t *testing.T) {
-	if !testenv.HasSrc() {
+	testenv.MustHaveSource(t)
-		t.Skip("source code not available")
-	}
 
 	re := regexp.MustCompile(`(strings|bytes).([A-Za-z]+)`)
 	if err := fs.WalkDir(os.DirFS("."), ".", func(path string, d fs.DirEntry, err error) error {