[dev.fuzz] testing: let -fuzztime specify a number of executions

-fuzztime now works similarly to -benchtime: if it's given a string
with an "x" suffix (as opposed to "s" or some other unit of
duration), the fuzzing system will generate and run a maximum number
of values.

This CL also implements tracking and printing counts, since most of
the work was already done.

Change-Id: I013007984b5adfc1a751c379dc98c8d46b4a97e9
Reviewed-on: https://go-review.googlesource.com/c/go/+/306909
Trust: Jay Conrod <jayconrod@google.com>
Trust: Katie Hockman <katie@golang.org>
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Katie Hockman <katie@golang.org>

1 files changed, 2 insertions, 8 deletions

diff --git a/src/testing/testing.go b/src/testing/testing.go
index 2ba93ad63d..48e9ee089f 100644
--- a/src/testing/testing.go
+++ b/src/testing/testing.go
@@ -1326,7 +1326,7 @@ func (f matchStringOnly) ImportPath() string                          { return "
 func (f matchStringOnly) StartTestLog(io.Writer)                      {}
 func (f matchStringOnly) StopTestLog() error                          { return errMain }
 func (f matchStringOnly) SetPanicOnExit0(bool)                        {}
-func (f matchStringOnly) CoordinateFuzzing(time.Duration, int, []corpusEntry, []reflect.Type, string, string) error {
+func (f matchStringOnly) CoordinateFuzzing(time.Duration, int64, int, []corpusEntry, []reflect.Type, string, string) error {
 	return errMain
 }
 func (f matchStringOnly) RunFuzzWorker(func(corpusEntry) error) error { return errMain }
@@ -1375,7 +1375,7 @@ type testDeps interface {
 	StartTestLog(io.Writer)
 	StopTestLog() error
 	WriteProfileTo(string, io.Writer, int) error
-	CoordinateFuzzing(time.Duration, int, []corpusEntry, []reflect.Type, string, string) error
+	CoordinateFuzzing(time.Duration, int64, int, []corpusEntry, []reflect.Type, string, string) error
 	RunFuzzWorker(func(corpusEntry) error) error
 	ReadCorpus(string, []reflect.Type) ([]corpusEntry, error)
 }
@@ -1417,12 +1417,6 @@ func (m *M) Run() (code int) {
 		m.exitCode = 2
 		return
 	}
-	if *fuzzDuration < 0 {
-		fmt.Fprintln(os.Stderr, "testing: -fuzztime can only be given a positive duration, or zero to run indefinitely")
-		flag.Usage()
-		m.exitCode = 2
-		return
-	}
 	if *matchFuzz != "" && *fuzzCacheDir == "" {
 		fmt.Fprintln(os.Stderr, "testing: internal error: -test.fuzzcachedir must be set if -test.fuzz is set")
 		flag.Usage()