code review 10264045: cmd/go: write coverage to file, add percentage statistic

src/pkg/testing/testing.go

 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 // Package testing provides support for automated testing of Go packages.
 // It is intended to be used in concert with the ``go test'' command, which automates
 // execution of any function of the form
 //     func TestXxx(*testing.T)
 // where Xxx can be any alphanumeric string (but the first letter must not be in
 // [a-z]) and serves to identify the test routine.
 // These TestXxx routines should be declared within the package they are testing.
 //
 // Tests and benchmarks may be skipped if not applicable like this:
 //     func TestTimeConsuming(t *testing.T) {
 //         if testing.Short() {
 //             t.Skip("skipping test in short mode.")
 //         }
 //         ...
 //     }
 //
 // Benchmarks
 //
 // Functions of the form
 //     func BenchmarkXxx(*testing.B)
 // are considered benchmarks, and are executed by the "go test" command when
-// the -test.bench flag is provided. Benchmarks are run sequentially.
+// its -bench flag is provided. Benchmarks are run sequentially.
 //
 // For a description of the testing flags, see
-// http://golang.org/cmd/go/#Description_of_testing_flags.
+// http://golang.org/cmd/go/#hdr-Description_of_testing_flags.
 //
 // A sample benchmark function looks like this:
 //     func BenchmarkHello(b *testing.B) {
 //         for i := 0; i < b.N; i++ {
 //             fmt.Sprintf("hello")
 //         }
 //     }
 //
 // The benchmark function must run the target code b.N times.
 // The benchmark package will vary b.N until the benchmark function lasts
@@ skipping 473 matching lines @@
                 if err != nil {
                         fmt.Fprintf(os.Stderr, "testing: %s\n", err)
                         os.Exit(2)
                 }
                 if err = pprof.Lookup("block").WriteTo(f, 0); err != nil {
                         fmt.Fprintf(os.Stderr, "testing: can't write %s: %s\n", *blockProfile, err)
                         os.Exit(2)
                 }
                 f.Close()
         }
-        coverReport()
+        if *cover != "" {
+                coverReport()
+        }
 }
 
 // toOutputDir returns the file name relocated, if required, to outputDir.
 // Simple implementation to avoid pulling in path/filepath.
 func toOutputDir(path string) string {
         if *outputDir == "" || path == "" {
                 return path
         }
         if runtime.GOOS == "windows" {
                 // On Windows, it's clumsy, but we can be almost always correct
@@ skipping 45 matching lines @@
                 for _, val := range strings.Split(*cpuListStr, ",") {
                         cpu, err := strconv.Atoi(val)
                         if err != nil || cpu <= 0 {
                                 fmt.Fprintf(os.Stderr, "testing: invalid value %q for -test.cpu", val)
                                 os.Exit(1)
                         }
                         cpuList = append(cpuList, cpu)
                 }
         }
 }