Adds benchmark support to gotest.

No benchmarks are run unless the --benchmarks=<regexp> flag
is specified on the gotest command line.  This change includes
sample benchmarks for regexp.

% gotest --benchmarks=.*
(standard test output redacted)
testing.BenchmarkSimpleMatch	200000	      7799 ns/op
testing.BenchmarkUngroupedMatch	20000	     76898 ns/op
testing.BenchmarkGroupedMatch	50000	     38148 ns/op

R=r, rsc
http://codereview.appspot.com/154173

Committer: Russ Cox <rsc@golang.org>

2 files changed, 23 insertions, 4 deletions

diff --git a/src/cmd/gotest/doc.go b/src/cmd/gotest/doc.go
index e1a87c43c..40c40fc1f 100644
--- a/src/cmd/gotest/doc.go
+++ b/src/cmd/gotest/doc.go
@@ -19,6 +19,12 @@ They should have signature
 
 	func TestXXX(t *testing.T) { ... }
 
+Benchmark functions can be written as well; they will be run only
+when the -benchmarks flag is provided.  Benchmarks should have
+signature
+
+	func BenchmarkXXX(b *testing.B) { ... }
+
 See the documentation of the testing package for more information.
 
 By default, gotest needs no arguments.  It compiles all the .go files
@@ -36,14 +42,15 @@ The resulting binary, called (for amd64) 6.out, has a couple of
 arguments.
 
 Usage:
-	6.out [-v] [-match pattern]
+	6.out [-v] [-match pattern] [-benchmarks pattern]
 
-The -v flag causes the tests to be logged as they run.  The --match
+The -v flag causes the tests to be logged as they run.  The -match
 flag causes only those tests whose names match the regular expression
 pattern to be run. By default all tests are run silently.  If all
 the specified test pass, 6.out prints PASS and exits with a 0 exit
 code.  If any tests fail, it prints FAIL and exits with a non-zero
-code.
+code.  The -benchmarks flag is analogous to the -match flag, but
+applies to benchmarks.  No benchmarks run by default.
 
 */
 package documentation
diff --git a/src/cmd/gotest/gotest b/src/cmd/gotest/gotest
index 584578e91..5f87b4791 100755
--- a/src/cmd/gotest/gotest
+++ b/src/cmd/gotest/gotest
@@ -118,6 +118,9 @@ importpath=$(gomake -s importpath)
 		echo 'gotest: error: no tests matching '$pattern in _test/$importpath.a $xofile 1>&2
 		exit 2
 	fi
+	# benchmarks are named BenchmarkFoo.
+	pattern='Benchmark([^a-z].*)?'
+	benchmarks=$(6nm -s _test/$importpath.a $xofile | egrep ' T .*·'$pattern'$' | grep -v '·.*[.·]' | sed 's/.* //; s/·/./')
 
 	# package spec
 	echo 'package main'
@@ -140,10 +143,19 @@ importpath=$(gomake -s importpath)
 		echo '	testing.Test{ "'$i'", '$i' },'
 	done
 	echo '}'
+	# benchmark array
+	echo 'var benchmarks = []testing.Benchmark {'
+	for i in $benchmarks
+	do
+		echo '	testing.Benchmark{ "'$i'", '$i' },'
+	done
+	echo '}'
+
 	# body
 	echo
 	echo 'func main() {'
-	echo '	testing.Main(tests)'
+	echo '	testing.Main(tests);'
+	echo '	testing.RunBenchmarks(benchmarks)'
 	echo '}'
 }>_testmain.go