Add comments and unit tests for GetHugePagesInfo()

Signed-off-by: sewon.oh <sewon.oh@samsung.com>

machine/machine.go

@@ -194,6 +194,8 @@ func getNodeIdFromCpuBus(cpuBusPath string, threadId int) (int, error) {
 }
 
 // GetHugePagesInfo returns information about pre-allocated huge pages
+// hugepagesDirectory should be top directory of hugepages
+// Such as: /sys/kernel/mm/hugepages/
 func GetHugePagesInfo(hugepagesDirectory string) ([]info.HugePagesInfo, error) {
 	var hugePagesInfo []info.HugePagesInfo
 	files, err := ioutil.ReadDir(hugepagesDirectory)

machine/testdata/hugepages/hugepages-1048576kB/nr_hugepages

@@ -0,0 +1 @@
+1

machine/testdata/hugepages/hugepages-2048kB/nr_hugepages

@@ -0,0 +1 @@
+2

machine/topology_test.go

@@ -143,3 +143,26 @@ func TestTopologyNodeId(t *testing.T) {
 		t.Errorf("Expected core 1234 , found %d", val)
 	}
 }
+
+func TestGetHugePagesInfo(t *testing.T) {
+	testPath := "./testdata/hugepages/"
+	expected := []info.HugePagesInfo{
+		{
+			NumPages: 1,
+			PageSize: 1048576,
+		},
+		{
+			NumPages: 2,
+			PageSize: 2048,
+		},
+	}
+
+	val, err := GetHugePagesInfo(testPath)
+	if err != nil {
+		t.Errorf("Failed to GetHugePagesInfo() for sample path %s: %v", testPath, err)
+	}
+
+	if !reflect.DeepEqual(expected, val) {
+		t.Errorf("Expected HugePagesInfo %+v, got %+v", expected, val)
+	}
+}