testing: expose subtest and subbenchmark functionality

Fixes #12166

Change-Id: Ie62cba2c39beb5732447ba3688c93c08ef12abb5
Reviewed-on: https://go-review.googlesource.com/18898
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>

src/testing/benchmark.go

@@ -14,7 +14,7 @@ import (
 	"time"
 )
 
-var matchBenchmarks = flag.String("test.bench", "", "regular expression to select benchmarks to run")
+var matchBenchmarks = flag.String("test.bench", "", "regular expression per path component to select benchmarks to run")
 var benchTime = flag.Duration("test.benchtime", 1*time.Second, "approximate run time for each benchmark")
 var benchmarkMemory = flag.Bool("test.benchmem", false, "print memory allocations for benchmarks")
 
@@ -380,7 +380,7 @@ func runBenchmarksInternal(matchString func(pat, str string) (bool, error), benc
 		common: common{name: "Main"},
 		benchFunc: func(b *B) {
 			for _, Benchmark := range bs {
-				b.runBench(Benchmark.Name, Benchmark.F)
+				b.Run(Benchmark.Name, Benchmark.F)
 			}
 		},
 		benchTime: *benchTime,
@@ -429,12 +429,12 @@ func (ctx *benchContext) processBench(b *B) {
 	}
 }
 
-// runBench benchmarks f as a subbenchmark with the given name. It reports
+// Run benchmarks f as a subbenchmark with the given name. It reports
 // whether there were any failures.
 //
 // A subbenchmark is like any other benchmark. A benchmark that calls Run at
 // least once will not be measured itself.
-func (b *B) runBench(name string, f func(b *B)) bool {
+func (b *B) Run(name string, f func(b *B)) bool {
 	// Since b has subbenchmarks, we will no longer run it as a benchmark itself.
 	// Release the lock and acquire it on exit to ensure locks stay paired.
 	b.hasSub = true
@@ -590,6 +590,9 @@ func (b *B) SetParallelism(p int) {
 
 // Benchmark benchmarks a single function. Useful for creating
 // custom benchmarks that do not use the "go test" command.
+//
+// If f calls Run, the result will be an estimate of running all its
+// subbenchmarks that don't call Run in sequence in a single benchmark.
 func Benchmark(f func(b *B)) BenchmarkResult {
 	b := &B{
 		common: common{

src/testing/sub_test.go

@@ -107,9 +107,6 @@ func TestTestContext(t *T) {
 	}
 }
 
-// TODO: remove this stub when API is exposed
-func (t *T) Run(name string, f func(t *T)) bool { return t.run(name, f) }
-
 func TestTRun(t *T) {
 	realTest := t
 	testCases := []struct {
@@ -330,9 +327,6 @@ func TestTRun(t *T) {
 	}
 }
 
-// TODO: remove this stub when API is exposed
-func (b *B) Run(name string, f func(b *B)) bool { return b.runBench(name, f) }
-
 func TestBRun(t *T) {
 	work := func(b *B) {
 		for i := 0; i < b.N; i++ {

src/testing/testing.go

@@ -548,9 +548,9 @@ func tRunner(t *T, fn func(t *T)) {
 	t.finished = true
 }
 
-// run runs f as a subtest of t called name. It reports whether f succeeded.
+// Run runs f as a subtest of t called name. It reports whether f succeeded.
 // Run will block until all its parallel subtests have completed.
-func (t *T) run(name string, f func(t *T)) bool {
+func (t *T) Run(name string, f func(t *T)) bool {
 	testName, ok := t.context.match.fullName(&t.common, name)
 	if !ok {
 		return true
@@ -721,7 +721,7 @@ func RunTests(matchString func(pat, str string) (bool, error), tests []InternalT
 		}
 		tRunner(t, func(t *T) {
 			for _, test := range tests {
-				t.run(test.Name, test.F)
+				t.Run(test.Name, test.F)
 			}
 			// Run catching the signal rather than the tRunner as a separate
 			// goroutine to avoid adding a goroutine during the sequential