testfix: dont break 8k goroutine limit under race

Godeps/Godeps.json

@@ -152,6 +152,10 @@
 			"Rev": "35738aceb35505bd3c77c2a618fb1947ca3f72da"
 		},
 		{
+			"ImportPath": "github.com/jbenet/go-detect-race",
+			"Rev": "3463798d9574bd0b7eca275dccc530804ff5216f"
+		},
+		{
 			"ImportPath": "github.com/jbenet/go-fuse-version",
 			"Rev": "b733dfc0597e1f6780510ee7afad8b6e3c7af3eb"
 		},

Godeps/_workspace/src/github.com/jbenet/go-detect-race/LICENSE

+The MIT License (MIT)
+
+Copyright (c) 2014 Juan Batiz-Benet
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

Godeps/_workspace/src/github.com/jbenet/go-detect-race/README.md

+# go-detect-race
+
+Check if the race detector is running.
+
+I didnt find a variable to check quickly enough so I made this.
+
+
+## Usage
+
+```go
+import (
+  detectrace "github.com/jbenet/go-detect-race"
+)
+
+func main() {
+  if detectrace.WithRace() {
+    // running with -race
+  } else {
+    // running without -race
+  }
+}
+```
+
+## Why?
+
+Because the race detector doesnt like massive stress tests. Example:
+https://groups.google.com/forum/#!topic/golang-nuts/XDPHUt2LE70
+
+## Why didn't you just use...
+
+Please tell me about a better way of doing this. It wasn't
+readily apparent to me, so I made this. But i would much prefer
+an env var or some already existing var from the stdlib :)

Godeps/_workspace/src/github.com/jbenet/go-detect-race/race.go

+package detectrace
+
+// WithRace returns whether the binary was compiled
+// with the race flag on.
+func WithRace() bool {
+	return withRace
+}

Godeps/_workspace/src/github.com/jbenet/go-detect-race/race_test.go

+package detectrace
+
+import (
+	"testing"
+)
+
+func TestWithRace(t *testing.T) {
+	t.Logf("WithRace() is %v\n", WithRace())
+}

Godeps/_workspace/src/github.com/jbenet/go-detect-race/withoutrace.go

+// +build !race
+
+package detectrace
+
+const withRace = false

Godeps/_workspace/src/github.com/jbenet/go-detect-race/withrace.go

+// +build race
+
+package detectrace
+
+const withRace = true

exchange/bitswap/bitswap_test.go

@@ -6,7 +6,9 @@ import (
 	"testing"
 	"time"
 
+	detectrace "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-detect-race"
 	context "github.com/jbenet/go-ipfs/Godeps/_workspace/src/golang.org/x/net/context"
+
 	blocks "github.com/jbenet/go-ipfs/blocks"
 	blocksutil "github.com/jbenet/go-ipfs/blocks/blocksutil"
 	tn "github.com/jbenet/go-ipfs/exchange/bitswap/testnet"
@@ -93,9 +95,15 @@ func TestLargeSwarm(t *testing.T) {
 	if testing.Short() {
 		t.SkipNow()
 	}
-	t.Parallel()
 	numInstances := 500
 	numBlocks := 2
+	if detectrace.WithRace() {
+		// when running with the race detector, 500 instances launches
+		// well over 8k goroutines. This hits a race detector limit.
+		numInstances = 100
+	} else {
+		t.Parallel()
+	}
 	PerformDistributionTest(t, numInstances, numBlocks)
 }