1 files changed, 25 insertions, 24 deletions
diff --git a/src/cmd/api/goapi_test.go b/src/cmd/api/goapi_test.go
index fc1bcc908a..282f26f708 100644
--- a/src/cmd/api/goapi_test.go
+++ b/src/cmd/api/goapi_test.go
@@ -9,16 +9,36 @@ import (
 	"flag"
 	"fmt"
 	"go/build"
-	"internal/testenv"
 	"io/ioutil"
 	"os"
-	"os/exec"
 	"path/filepath"
 	"sort"
 	"strings"
+	"sync"
 	"testing"
 )
 
+func TestMain(m *testing.M) {
+	flag.Parse()
+	for _, c := range contexts {
+		c.Compiler = build.Default.Compiler
+	}
+
+	// Warm up the import cache in parallel.
+	var wg sync.WaitGroup
+	for _, context := range contexts {
+		context := context
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			_ = NewWalker(context, filepath.Join(build.Default.GOROOT, "src"))
+		}()
+	}
+	wg.Wait()
+
+	os.Exit(m.Run())
+}
+
 var (
 	updateGolden = flag.Bool("updategolden", false, "update golden files")
 )
@@ -164,25 +184,12 @@ func TestSkipInternal(t *testing.T) {
 }
 
 func BenchmarkAll(b *testing.B) {
-	stds, err := exec.Command(testenv.GoToolPath(b), "list", "std").Output()
-	if err != nil {
-		b.Fatal(err)
-	}
-	b.ResetTimer()
-	pkgNames := strings.Fields(string(stds))
-
-	for _, c := range contexts {
-		c.Compiler = build.Default.Compiler
-	}
-
 	for i := 0; i < b.N; i++ {
 		for _, context := range contexts {
 			w := NewWalker(context, filepath.Join(build.Default.GOROOT, "src"))
-			for _, name := range pkgNames {
-				if name != "unsafe" && !strings.HasPrefix(name, "cmd/") && !internalPkg.MatchString(name) {
-					pkg, _ := w.Import(name)
-					w.export(pkg)
-				}
+			for _, name := range w.stdPackages {
+				pkg, _ := w.Import(name)
+				w.export(pkg)
 			}
 			w.Features()
 		}
@@ -190,9 +197,6 @@ func BenchmarkAll(b *testing.B) {
 }
 
 func TestIssue21181(t *testing.T) {
-	for _, c := range contexts {
-		c.Compiler = build.Default.Compiler
-	}
 	for _, context := range contexts {
 		w := NewWalker(context, "testdata/src/issue21181")
 		pkg, err := w.Import("p")
@@ -205,9 +209,6 @@ func TestIssue21181(t *testing.T) {
 }
 
 func TestIssue29837(t *testing.T) {
-	for _, c := range contexts {
-		c.Compiler = build.Default.Compiler
-	}
 	for _, context := range contexts {
 		w := NewWalker(context, "testdata/src/issue29837")
 		_, err := w.Import("p")