cmd/dist: use goTest for manual go test invocations

This CL rewrites everywhere in dist that manually constructs an
exec.Cmd to run "go test" to use the goTest abstraction. All remaining
invocations of "go test" after this CL construct the command line
manually, but ultimately use addCmd to execute it.

I traced all exec calls from cmd/dist on linux/amd64 and this makes
only no-op changes (such as re-arranging the order of flags).

For #37486.

Change-Id: Idc7497e39bac04def7ddaf2010881c9623e76fd4
Reviewed-on: https://go-review.googlesource.com/c/go/+/450015
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Austin Clements <austin@google.com>

src/cmd/dist/test.go

@@ -550,39 +550,18 @@ func (t *tester) registerStdTest(pkg string) {
 			defer timelog("end", dt.name)
 			ranGoTest = true
 
-			timeoutSec := 180
+			timeoutSec := 180 * time.Second
 			for _, pkg := range stdMatches {
 				if pkg == "cmd/go" {
 					timeoutSec *= 3
 					break
 				}
 			}
-			args := []string{
-				"test",
-				"-short=" + short(),
-				t.tags(),
-				t.timeout(timeoutSec),
-			}
-			if gcflags != "" {
-				args = append(args, "-gcflags=all="+gcflags)
-			}
-			if t.race {
-				args = append(args, "-race")
-			}
-			if t.msan {
-				args = append(args, "-msan")
-			}
-			if t.asan {
-				args = append(args, "-asan")
-			}
-			if t.compileOnly {
-				args = append(args, "-run=^$")
-			}
-			args = append(args, stdMatches...)
-			cmd := exec.Command(gorootBinGo, args...)
-			cmd.Stdout = os.Stdout
-			cmd.Stderr = os.Stderr
-			return cmd.Run()
+			return (&goTest{
+				timeout: timeoutSec,
+				gcflags: gcflags,
+				pkgs:    stdMatches,
+			}).run(t)
 		},
 	})
 }
@@ -603,23 +582,13 @@ func (t *tester) registerRaceBenchTest(pkg string) {
 			timelog("start", dt.name)
 			defer timelog("end", dt.name)
 			ranGoBench = true
-			args := []string{
-				"test",
-				"-short=" + short(),
-				"-race",
-				t.timeout(1200), // longer timeout for race with benchmarks
-				"-run=^$",       // nothing. only benchmarks.
-				"-benchtime=.1s",
-				"-cpu=4",
-			}
-			if !t.compileOnly {
-				args = append(args, "-bench=.*")
-			}
-			args = append(args, benchMatches...)
-			cmd := exec.Command(gorootBinGo, args...)
-			cmd.Stdout = os.Stdout
-			cmd.Stderr = os.Stderr
-			return cmd.Run()
+			return (&goTest{
+				timeout: 1200 * time.Second, // longer timeout for race with benchmarks
+				race:    true,
+				bench:   true,
+				cpu:     "4",
+				pkgs:    benchMatches,
+			}).run(t)
 		},
 	})
 }
@@ -789,9 +758,10 @@ func (t *tester) registerTests() {
 
 				// Run `go test fmt` in the moved GOROOT, without explicitly setting
 				// GOROOT in the environment. The 'go' command should find itself.
-				cmd := exec.Command(filepath.Join(moved, "bin", "go"), "test", "fmt")
-				cmd.Stdout = os.Stdout
-				cmd.Stderr = os.Stderr
+				cmd := (&goTest{
+					goroot: moved,
+					pkg:    "fmt",
+				}).command(t)
 				unsetEnv(cmd, "GOROOT")
 				unsetEnv(cmd, "GOCACHE") // TODO(bcmills): ...why‽
 				err := cmd.Run()