Add test demonstrating snapshot restore

Issue: #78

devices/erebor/features/file_server.feature

@@ -19,3 +19,7 @@ Feature: A FreeBSD ZFS NAS
     Then my zpool has more storage available
 
   Scenario: Restoring from a snapshot
+    Given that a snapshot has been made
+    When a file has been deleted
+    And I restore from the snapshot
+    Then my files are all still available

devices/erebor/features/step_definitions/initial_steps.rb

@@ -108,10 +108,26 @@ def delete_zpool(name)
   @vagrant.exec "sudo zpool replace testpool /dev/md0 /dev/md4"
   @vagrant.exec "sudo zpool replace testpool /dev/md1 /dev/md5"
   @vagrant.exec "sudo zpool replace testpool /dev/md2 /dev/md6"
+  @vagrant.exec "sudo zpool online -e testpool /dev/md4"
+  @vagrant.exec "sudo zpool online -e testpool /dev/md5"
   @vagrant.exec "sudo zpool online -e testpool /dev/md6"
 end
 
 Then('my zpool has more storage available') do
   @new_size = @vagrant.exec "zpool list | grep testpool | awk '{ print $2 }'"
   expect(@new_size).not_to eq @start_size
 end
+
+Given('that a snapshot has been made') do
+  @vagrant.exec "sudo zfs snapshot testpool@test"
+end
+
+When('a file has been deleted') do
+  @vagrant.exec "sudo rm /testpool/data/Moby_Dick.txt"
+  output = @vagrant.exec "ls /testpool/data/"
+  expect(output).not_to match(/Moby_Dick\.txt/)
+end
+
+When('I restore from the snapshot') do
+  @vagrant.exec "sudo cp /testpool/.zfs/snapshot/test/data/Moby_Dick.txt /testpool/data/Moby_Dick.txt"
+end