buildinfo: add func TestingLinked

Change-Id: I664f72ec04748079929d0ad96e24b33bc14c6c77

pkg/buildinfo/buildinfo.go

@@ -1,3 +1,19 @@
+/*
+Copyright 2014 The Camlistore Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
 // Package buildinfo provides information about the current build.
 package buildinfo
 
@@ -15,3 +31,14 @@ func Version() string {
 	}
 	return "unknown"
 }
+
+var testingLinked func() bool
+
+// TestingLinked reports whether the "testing" package is linked into the binary.
+// It always returns false for Go 1.1.
+func TestingLinked() bool {
+	if testingLinked == nil {
+		return false
+	}
+	return testingLinked()
+}

pkg/buildinfo/buildinfo_test.go

@@ -0,0 +1,44 @@
+/*
+Copyright 2014 The Camlistore Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package buildinfo
+
+import (
+	"go/build"
+	"testing"
+)
+
+func TestTestingLinked(t *testing.T) {
+	if !isGo12() {
+		t.Skip("skipping test for Go 1.1")
+	}
+	if testingLinked == nil {
+		t.Fatal("go1.2+ but testingLinked is nil")
+	}
+	if !testingLinked() {
+		t.Error("testingLinked = false; want true")
+	}
+}
+
+// isGo12 reports whether the Go version is 1.2 or higher
+func isGo12() bool {
+	for _, v := range build.Default.ReleaseTags {
+		if v == "go1.2" {
+			return true
+		}
+	}
+	return false
+}

pkg/buildinfo/testinglinked.go

@@ -0,0 +1,27 @@
+// +build go1.2
+
+/*
+Copyright 2014 The Camlistore Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package buildinfo
+
+import "flag"
+
+func init() {
+	testingLinked = func() bool {
+		return flag.CommandLine.Lookup("test.v") != nil
+	}
+}