patch2: fix some comments and nit

go/callgraph/rta/rta_test.go

@@ -38,8 +38,9 @@ var baseConfig = &packages.Config{
  packages.NeedTypes,
 }
 
-// TestRTASingleFile runs RTA on each testdata/*.go file and compares the
-// results with the expectations expressed in the WANT comment.
+// TestRTASingleFile runs RTA on each testdata/*.txtar file containing a single
+// go file and compares the results with the expectations expressed in the WANT
+// comment.
 func TestRTASingleFile(t *testing.T) {
  archivePaths := []string{
  "testdata/func.txtar",
@@ -73,7 +74,7 @@ func TestRTASingleFile(t *testing.T) {
 }
 
 // TestRTAOnPackages runs RTA on a go module which contains multiple packages to test the case
-// that the interface definition and its implementations locate in different packages.
+// when an interface has implementations across different packages.
 func TestRTAOnPackages(t *testing.T) {
  baseConfig.Dir = restoreArchive(t, "testdata/multipkgs.txtar")
  pkgs, err := packages.Load(baseConfig, "./...")
@@ -83,9 +84,8 @@ func TestRTAOnPackages(t *testing.T) {
 
  var f *ast.File
  for _, p := range pkgs {
- // we retrieve first file inside main package as the expected result stays there
- // this implies the main package should only have one file or the expected result is stored
- // in the first file of main package
+ // We assume the packages have a single file or
+ // the wanted result is in the first file of the main package.
  if p.Name == "main" {
  f = p.Syntax[0]
  }
@@ -110,8 +110,8 @@ func TestRTAOnPackages(t *testing.T) {
 }
 
 // restoreArchive restores a go module from the archive file,
-// and put all contents in a temporary folder
-func restoreArchive(t *testing.T, achieveFilePath string) (dir string) {
+// and puts all contents in a temporary folder.
+func restoreArchive(t *testing.T, achieveFilePath string) string {
  ar, err := txtar.ParseFile(achieveFilePath)
  if err != nil {
  t.Fatal(err)
@@ -121,8 +121,7 @@ func restoreArchive(t *testing.T, achieveFilePath string) (dir string) {
  if err != nil {
  t.Fatal(err)
  }
- dir = testfiles.CopyToTmp(t, fs)
- return
+ return testfiles.CopyToTmp(t, fs)
 }
 
 // check tests the RTA analysis results against the test expectations