diff --git a/README.md b/README.md
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--- a/README.md
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@@ -1089,18 +1089,22 @@ You'll get more graph practice in Skiena's book (see Books section below) and th
     - [ ] strace: https://en.wikipedia.org/wiki/Strace
     - [ ] tcpdump: https://danielmiessler.com/study/tcpdump/
 
-- [ ] **Testing**
+- [x] **Testing**
+    - To cover:
+        - how unit testing works
+        - what are mock objects
+        - what is integration testing
+        - what is dependency injection
     - [x] Agile Software Testing with James Bach: https://www.youtube.com/watch?v=SAhJf36_u5U
     - [x] Open Lecture by James Bach on Software Testing: https://www.youtube.com/watch?v=ILkT_HV9DVU
     - [x] Steve Freeman - Test-Driven Development (that’s not what we meant): https://vimeo.com/83960706
         - slides: http://gotocon.com/dl/goto-berlin-2013/slides/SteveFreeman_TestDrivenDevelopmentThatsNotWhatWeMeant.pdf
     - [x] TDD is dead. Long live testing.: http://david.heinemeierhansson.com/2014/tdd-is-dead-long-live-testing.html
-    - [ ] Video series (152 videos): https://www.youtube.com/watch?v=nzJapzxH_rE&list=PLAwxTw4SYaPkWVHeC_8aSIbSxE_NXI76g
-    - [ ] Test-Driven Web Development with Python: http://www.obeythetestinggoat.com/pages/book.html#toc
-    - how unit testing works
-    - what are mock objects
-    - what is integration testing
-    - what is dependency injection
+    - [x] Video series (152 videos): https://www.youtube.com/watch?v=nzJapzxH_rE&list=PLAwxTw4SYaPkWVHeC_8aSIbSxE_NXI76g
+    - [x] Test-Driven Web Development with Python: http://www.obeythetestinggoat.com/pages/book.html#toc
+    - [x] Dependency injection:
+        - [x] https://www.youtube.com/watch?v=IKD2-MAkXyQ
+        - [x] http://jasonpolites.github.io/tao-of-testing/ch3-1.1.html
 
 - [ ] **Design patterns**
     - [ ] CS164 Lecture 3 Design Patterns: https://youtu.be/mym5m-GKG0Q?t=660