pkg/fs: test, bench, and drop unnecessary check in ListBuckets

There is now a simple test and a benchmark for ListBuckets. I also
dropped an unnecessary check that was simply repeated from above,
guaranteed to be true.

pkg/fs/fs-bucket.go

@@ -78,7 +78,7 @@ func (fs Filesystem) ListBuckets() ([]BucketMetadata, *probe.Error) {
 		}
 		// If directories are found with odd names, skip them.
 		dirName := strings.ToLower(file.Name())
-		if file.IsDir() && !IsValidBucketName(dirName) {
+		if !IsValidBucketName(dirName) {
 			continue
 		}
 		metadata := BucketMetadata{

pkg/fs/fs-bucket_test.go

@@ -19,10 +19,51 @@ package fs
 import (
 	"io/ioutil"
 	"os"
+	"strconv"
 	"strings"
 	"testing"
 )
 
+func TestListBuckets(t *testing.T) {
+	// Make a temporary directory to use as the filesystem.
+	directory, fserr := ioutil.TempDir("", "minio-benchmark")
+	if fserr != nil {
+		t.Fatal(fserr)
+	}
+	defer os.RemoveAll(directory)
+
+	// Create the filesystem.
+	filesystem, err := New(directory, 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Create a few buckets.
+	for i := 0; i < 10; i++ {
+		err = filesystem.MakeBucket("testbucket."+strconv.Itoa(i), "public-read")
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	// List, and ensure that they are all there.
+	metadatas, err := filesystem.ListBuckets()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(metadatas) != 10 {
+		t.Errorf("incorrect length of metadatas (%i)\n", len(metadatas))
+	}
+
+	// Iterate over the buckets, ensuring that the name is correct.
+	for i := 0; i < len(metadatas); i++ {
+		if !strings.Contains(metadatas[i].Name, "testbucket") {
+			t.Fail()
+		}
+	}
+}
+
 func TestDeleteBucket(t *testing.T) {
 	// Make a temporary directory to use as the filesystem.
 	directory, fserr := ioutil.TempDir("", "minio-benchmark")
@@ -44,6 +85,39 @@ func TestDeleteBucket(t *testing.T) {
 	}
 }
 
+func BenchmarkListBuckets(b *testing.B) {
+	// Make a temporary directory to use as the filesystem.
+	directory, fserr := ioutil.TempDir("", "minio-benchmark")
+	if fserr != nil {
+		b.Fatal(fserr)
+	}
+	defer os.RemoveAll(directory)
+
+	// Create the filesystem.
+	filesystem, err := New(directory, 0)
+	if err != nil {
+		b.Fatal(err)
+	}
+
+	// Create a few buckets.
+	for i := 0; i < 20; i++ {
+		err = filesystem.MakeBucket("bucket."+strconv.Itoa(i), "public-read")
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+
+	b.ResetTimer()
+
+	// List the buckets over and over and over.
+	for i := 0; i < b.N; i++ {
+		_, err = filesystem.ListBuckets()
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
 func BenchmarkDeleteBucket(b *testing.B) {
 	// Make a temporary directory to use as the filesystem.
 	directory, fserr := ioutil.TempDir("", "minio-benchmark")