Merge pull request #493 from aboodman/counter-test

counter: add a unit test

clients/counter/counter.go

@@ -9,8 +9,11 @@ import (
 	"github.com/attic-labs/noms/types"
 )
 
+var (
+	dsFlags = dataset.NewFlags()
+)
+
 func main() {
-	dsFlags := dataset.NewFlags()
 	flag.Parse()
 
 	ds := dsFlags.CreateDataset()

clients/counter/counter_test.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"io/ioutil"
+	"os"
+	"path"
+	"testing"
+
+	"github.com/attic-labs/noms/Godeps/_workspace/src/github.com/stretchr/testify/assert"
+	"github.com/attic-labs/noms/clients/util"
+	"github.com/attic-labs/noms/d"
+)
+
+var (
+	dir string
+	ldb string
+)
+
+func TestMain(m *testing.M) {
+	dir, err := ioutil.TempDir(os.TempDir(), "nomstest")
+	d.Chk.NoError(err)
+	ldb = path.Join(dir, "ldb")
+
+	defer d.Chk.NoError(os.RemoveAll(dir))
+
+	os.Exit(m.Run())
+}
+
+func TestCounter(t *testing.T) {
+	assert := assert.New(t)
+	args := []string{"counter", "-ldb", ldb, "-ds", "counter"}
+	assert.Equal("1\n", util.Run(main, args))
+	assert.Equal("2\n", util.Run(main, args))
+	assert.Equal("3\n", util.Run(main, args))
+}

clients/util/run.go

@@ -0,0 +1,33 @@
+package util
+
+import (
+	"io/ioutil"
+	"os"
+
+	"github.com/attic-labs/noms/d"
+)
+
+func Run(f func(), args []string) string {
+	origArgs := os.Args
+	origOut := os.Stdout
+	out, err := ioutil.TempFile(os.TempDir(), "")
+
+	defer func() {
+		os.Args = origArgs
+		os.Stdout = origOut
+		out.Close()
+		d.Chk.NoError(os.Remove(out.Name()))
+	}()
+
+	d.Chk.NoError(err)
+
+	os.Args = args
+	os.Stdout = out
+	f()
+
+	_, err = os.Stdout.Seek(0, 0)
+	d.Chk.NoError(err)
+	b, err := ioutil.ReadAll(os.Stdout)
+	d.Chk.NoError(err)
+	return string(b)
+}