Add tests for GetHugePageSize

Add tests to avoid regressions

Signed-off-by: Odin Ugedal <odin@ugedal.com>

libcontainer/cgroups/utils.go

@@ -409,14 +409,22 @@ func RemovePaths(paths map[string]string) (err error) {
 }
 
 func GetHugePageSize() ([]string, error) {
-	var pageSizes []string
-	sizeList := []string{"B", "KB", "MB", "GB", "TB", "PB"}
 	files, err := ioutil.ReadDir("/sys/kernel/mm/hugepages")
 	if err != nil {
-		return pageSizes, err
+		return []string{}, err
 	}
+	var fileNames []string
 	for _, st := range files {
-		nameArray := strings.Split(st.Name(), "-")
+		fileNames = append(fileNames, st.Name())
+	}
+	return getHugePageSizeFromFilenames(fileNames)
+}
+
+func getHugePageSizeFromFilenames(fileNames []string) ([]string, error) {
+	var pageSizes []string
+	sizeList := []string{"B", "KB", "MB", "GB", "TB", "PB"}
+	for _, fileName := range fileNames {
+		nameArray := strings.Split(fileName, "-")
 		pageSize, err := units.RAMInBytes(nameArray[1])
 		if err != nil {
 			return []string{}, err

libcontainer/cgroups/utils_test.go

@@ -4,6 +4,7 @@ package cgroups
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"reflect"
 	"strings"
@@ -421,3 +422,38 @@ func TestFindCgroupMountpointAndRoot(t *testing.T) {
 		}
 	}
 }
+
+func TestGetHugePageSizeImpl(t *testing.T) {
+
+	testCases := []struct {
+		inputFiles      []string
+		outputPageSizes []string
+		err             error
+	}{
+		{
+			inputFiles:      []string{"hugepages-1048576kB", "hugepages-2048kB", "hugepages-32768kB", "hugepages-64kB"},
+			outputPageSizes: []string{"1GB", "2MB", "32MB", "64KB"},
+			err:             nil,
+		},
+		{
+			inputFiles:      []string{},
+			outputPageSizes: []string{},
+			err:             nil,
+		},
+		{
+			inputFiles:      []string{"hugepages-a"},
+			outputPageSizes: []string{},
+			err:             errors.New("invalid size: 'a'"),
+		},
+	}
+
+	for _, c := range testCases {
+		pageSizes, err := getHugePageSizeFromFilenames(c.inputFiles)
+		if len(pageSizes) != 0 && len(c.outputPageSizes) != 0 && !reflect.DeepEqual(pageSizes, c.outputPageSizes) {
+			t.Errorf("expected %s, got %s", c.outputPageSizes, pageSizes)
+		}
+		if err != nil && err.Error() != c.err.Error() {
+			t.Errorf("expected error %s, got %s", c.err, err)
+		}
+	}
+}