test(mountprobe): add unit tests for MountProbe (#545)

- add unit test case for MountProbe

Fixes #253

Signed-off-by: Aditya Jain <[email protected]>

cmd/ndm_daemonset/probe/mountprobe_test.go

@@ -0,0 +1,148 @@
+/*
+Copyright 2019 The OpenEBS 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 probe
+
+import (
+	"io/ioutil"
+	"os"
+	"path"
+	"syscall"
+	"testing"
+
+	"github.com/openebs/node-disk-manager/blockdevice"
+	"github.com/openebs/node-disk-manager/pkg/mount"
+)
+
+const (
+	mountsFilePath   = "/proc/1/mounts"
+	sampleMountsFile = `
+sysfs /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0
+proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0
+udev /dev devtmpfs rw,nosuid,noexec,relatime,size=4027936k,nr_inodes=1006984,mode=755 0 0
+devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0
+tmpfs /run tmpfs rw,nosuid,nodev,noexec,relatime,size=811944k,mode=755 0 0
+/dev/sda1 / ext4 rw,relatime,errors=remount-ro 0 0
+none /sys/fs/bpf bpf rw,nosuid,nodev,noexec,relatime,mode=700 0 0
+cgroup /sys/fs/cgroup/rdma cgroup rw,nosuid,nodev,noexec,relatime,rdma 0 0
+cgroup /sys/fs/cgroup/freezer cgroup rw,nosuid,nodev,noexec,relatime,freezer 0 0
+/dev/loop4 /snap/core18/1988 squashfs ro,nodev,relatime 0 0
+/dev/loop0 /snap/core/10823 squashfs ro,nodev,relatime 0 0
+/dev/loop3 /snap/gnome-3-28-1804/145 squashfs ro,nodev,relatime 0 0
+/dev/loop1 /snap/core/10859 squashfs ro,nodev,relatime 0 0
+/dev/loop2 /snap/core18/1944 squashfs ro,nodev,relatime 0 0
+/dev/sda4 /boot/efi vfat rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro 0 0
+/dev/sda2 /home ext4 rw,relatime 0 0
+`
+)
+
+func TestMountProbeFillBlockDeviceDetails(t *testing.T) {
+	mp := &mountProbe{}
+
+	t.Run("DevPath empty", func(t *testing.T) {
+		bd := blockdevice.BlockDevice{}
+		mp.FillBlockDeviceDetails(&bd)
+		if len(bd.FSInfo.MountPoint) > 0 {
+			t.Errorf("Expected mountpoints to be empty, found %v",
+				bd.FSInfo.MountPoint)
+		}
+	})
+
+	t.Run("Device not mounted", func(t *testing.T) {
+		// Chroot into a tmp dir
+		err := enterFakeRoot(t)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer exitFakeRoot()
+
+		bd := blockdevice.BlockDevice{
+			Identifier: blockdevice.Identifier{
+				DevPath: "/dev/sda5",
+			},
+		}
+		mp.FillBlockDeviceDetails(&bd)
+		if len(bd.FSInfo.MountPoint) > 0 {
+			t.Errorf("Expected mountpoints to be empty, found %v",
+				bd.FSInfo.MountPoint)
+		}
+	})
+
+	t.Run("Device mounted", func(t *testing.T) {
+		err := enterFakeRoot(t)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer exitFakeRoot()
+
+		bd := blockdevice.BlockDevice{
+			Identifier: blockdevice.Identifier{
+				DevPath: "/dev/sda1",
+			}}
+		mp.FillBlockDeviceDetails(&bd)
+		if len(bd.FSInfo.MountPoint) <= 0 || bd.FSInfo.MountPoint[0] != "/" {
+			t.Errorf("Expected mountpoint to be %v, found %v",
+				"/", bd.FSInfo.MountPoint)
+		}
+	})
+}
+
+// enterFakeRoot creates a fake root in a tmp folder and
+// chroots to that folder.
+func enterFakeRoot(t *testing.T) error {
+	fakeRootPath := t.TempDir()
+	realMountsPath := path.Join(fakeRootPath, mount.HostMountsFilePath[1:])
+
+	t.Helper()
+
+	// Create the mounts file at the expected path in the tmp dir
+	err := os.MkdirAll(path.Dir(realMountsPath), 0755)
+	if err != nil {
+		return err
+	}
+	err = createMountsFile(realMountsPath)
+	if err != nil {
+		return err
+	}
+
+	// Change dir to current root to get chroot back later
+	err = os.Chdir("/")
+	if err != nil {
+		return err
+	}
+
+	// Chroot into the tmp dir
+	err = syscall.Chroot(fakeRootPath)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// exitFakeRoot exits from the chrooted environment
+func exitFakeRoot() error {
+	// We need to chroot to the original root. The current dir
+	// is the actual root since we changed dir to / while
+	// entering fake root
+	if err := syscall.Chroot("."); err != nil {
+		return err
+	}
+	return nil
+}
+
+func createMountsFile(dest string) error {
+	return ioutil.WriteFile(dest, []byte(sampleMountsFile), 0444)
+}