test: add -s flag to commands understood by run.go

If -s is specified, each file is considered a separate
package even if multiple files have the same package names.

For instance, the action and flag "errorcheckdir -s"
will compile all files in the respective directory as
individual packages.

Change-Id: Ic5c2f9e915a669433f66c2d3fe0ac068227a502f
Reviewed-on: https://go-review.googlesource.com/24313
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

test/run.go

@@ -306,7 +306,9 @@ func goDirFiles(longdir string) (filter []os.FileInfo, err error) {
 
 var packageRE = regexp.MustCompile(`(?m)^package (\w+)`)
 
-func goDirPackages(longdir string) ([][]string, error) {
+// If singlefilepkgs is set, each file is considered a separate package
+// even if the package names are the same.
+func goDirPackages(longdir string, singlefilepkgs bool) ([][]string, error) {
 	files, err := goDirFiles(longdir)
 	if err != nil {
 		return nil, err
@@ -324,7 +326,7 @@ func goDirPackages(longdir string) ([][]string, error) {
 			return nil, fmt.Errorf("cannot find package name in %s", name)
 		}
 		i, ok := m[pkgname[1]]
-		if !ok {
+		if singlefilepkgs || !ok {
 			i = len(pkgs)
 			pkgs = append(pkgs, nil)
 			m[pkgname[1]] = i
@@ -464,12 +466,14 @@ func (t *test) run() {
 
 	var args, flags []string
 	wantError := false
+	singlefilepkgs := false
 	f := strings.Fields(action)
 	if len(f) > 0 {
 		action = f[0]
 		args = f[1:]
 	}
 
+	// TODO: Clean up/simplify this switch statement.
 	switch action {
 	case "rundircmpout":
 		action = "rundir"
@@ -485,14 +489,6 @@ func (t *test) run() {
 	case "errorcheck", "errorcheckdir", "errorcheckoutput":
 		t.action = action
 		wantError = true
-		for len(args) > 0 && strings.HasPrefix(args[0], "-") {
-			if args[0] == "-0" {
-				wantError = false
-			} else {
-				flags = append(flags, args[0])
-			}
-			args = args[1:]
-		}
 	case "skip":
 		if *runSkips {
 			break
@@ -505,6 +501,19 @@ func (t *test) run() {
 		return
 	}
 
+	// collect flags
+	for len(args) > 0 && strings.HasPrefix(args[0], "-") {
+		switch args[0] {
+		case "-0":
+			wantError = false
+		case "-s":
+			singlefilepkgs = true
+		default:
+			flags = append(flags, args[0])
+		}
+		args = args[1:]
+	}
+
 	t.makeTempDir()
 	if !*keep {
 		defer os.RemoveAll(t.tempDir)
@@ -578,7 +587,7 @@ func (t *test) run() {
 	case "compiledir":
 		// Compile all files in the directory in lexicographic order.
 		longdir := filepath.Join(cwd, t.goDirName())
-		pkgs, err := goDirPackages(longdir)
+		pkgs, err := goDirPackages(longdir, singlefilepkgs)
 		if err != nil {
 			t.err = err
 			return
@@ -594,7 +603,7 @@ func (t *test) run() {
 		// errorcheck all files in lexicographic order
 		// useful for finding importing errors
 		longdir := filepath.Join(cwd, t.goDirName())
-		pkgs, err := goDirPackages(longdir)
+		pkgs, err := goDirPackages(longdir, singlefilepkgs)
 		if err != nil {
 			t.err = err
 			return
@@ -631,7 +640,7 @@ func (t *test) run() {
 		// Compile all files in the directory in lexicographic order.
 		// then link as if the last file is the main package and run it
 		longdir := filepath.Join(cwd, t.goDirName())
-		pkgs, err := goDirPackages(longdir)
+		pkgs, err := goDirPackages(longdir, singlefilepkgs)
 		if err != nil {
 			t.err = err
 			return