Add unit tests for fstab stage

Refs: #405

internal/osbuild/fstab_stage_test.go

@@ -0,0 +1,52 @@
+package osbuild
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNewFSTabStage(t *testing.T) {
+	expectedStage := &Stage{
+		Name:    "org.osbuild.fstab",
+		Options: &FSTabStageOptions{},
+	}
+	actualStage := NewFSTabStage(&FSTabStageOptions{})
+	assert.Equal(t, expectedStage, actualStage)
+}
+
+func TestAddFilesystem(t *testing.T) {
+	options := &FSTabStageOptions{}
+	filesystems := []*FSTabEntry{
+		{
+			UUID:    "76a22bf4-f153-4541-b6c7-0332c0dfaeac",
+			VFSType: "ext4",
+			Path:    "/",
+			Options: "defaults",
+			Freq:    1,
+			PassNo:  1,
+		},
+		{
+			UUID:    "bba22bf4-f153-4541-b6c7-0332c0dfaeac",
+			VFSType: "xfs",
+			Path:    "/home",
+			Options: "defaults",
+			Freq:    1,
+			PassNo:  2,
+		},
+		{
+			UUID:    "cca22bf4-f153-4541-b6c7-0332c0dfaeac",
+			VFSType: "xfs",
+			Path:    "/var",
+			Options: "defaults",
+			Freq:    1,
+			PassNo:  1,
+		},
+	}
+
+	for i, fs := range filesystems {
+		options.AddFilesystem(fs.UUID, fs.VFSType, fs.Path, fs.Options, fs.Freq, fs.PassNo)
+		assert.Equal(t, options.FileSystems[i], fs)
+	}
+	assert.Equal(t, len(filesystems), len(options.FileSystems))
+}