Added a lot of Oxford commas

[ci skip] A regular expression was used to find a lot of missing Oxford
commas and add them.  The regular expression was as follows.

", ([a-zA-Z0-9.\`:'\"]+ ){1,6}(or|and) "

1 files changed, 2 insertions, 2 deletions

diff --git a/guides/source/testing.md b/guides/source/testing.md
index 2c2f1028e1..0a6d2d6555 100644
--- a/guides/source/testing.md
+++ b/guides/source/testing.md
@@ -1131,7 +1131,7 @@ If you're familiar with the HTTP protocol, you'll know that `get` is a type of r
 * `head`
 * `delete`
 
-All of request types have equivalent methods that you can use. In a typical C.R.U.D. application you'll be using `get`, `post`, `put` and `delete` more often.
+All of request types have equivalent methods that you can use. In a typical C.R.U.D. application you'll be using `get`, `post`, `put`, and `delete` more often.
 
 NOTE: Functional tests do not verify whether the specified request type is accepted by the action, we're more concerned with the result. Request tests exist for this use case to make your tests more purposeful.
 
@@ -1596,7 +1596,7 @@ manually with: `ActionMailer::Base.deliveries.clear`
 
 ### Functional Testing
 
-Functional testing for mailers involves more than just checking that the email body, recipients and so forth are correct. In functional mail tests you call the mail deliver methods and check that the appropriate emails have been appended to the delivery list. It is fairly safe to assume that the deliver methods themselves do their job. You are probably more interested in whether your own business logic is sending emails when you expect them to go out. For example, you can check that the invite friend operation is sending an email appropriately:
+Functional testing for mailers involves more than just checking that the email body, recipients, and so forth are correct. In functional mail tests you call the mail deliver methods and check that the appropriate emails have been appended to the delivery list. It is fairly safe to assume that the deliver methods themselves do their job. You are probably more interested in whether your own business logic is sending emails when you expect them to go out. For example, you can check that the invite friend operation is sending an email appropriately:
 
 ```ruby
 require 'test_helper'