Add unit test guidelines

README.md

@@ -74,6 +74,9 @@ While not a requisite (since we're coving most of it in depth in this tutorial)
 * [What is the 'clearfix' class for?](docs/clearfix.md)
 * [ExpressionChangedAfterItHasBeenCheckedError](https://blog.angular-university.io/angular-debugging/)
 
+## Other Articles
+* [Unit Testing](docs/unittesting.md)
+
 ## AppFactory Customizations
 * [Entity Not Found Exception](https://gist.github.com/aodendaal/86fedc36b3593a4adbd4e35ef0327702)
 * [Angular 2 User Profile Self-Help Editor](https://github.com/aodendaal/abp-ng2-profile-editor)

docs/unittesting.md

@@ -0,0 +1,14 @@
+# Unit Testing
+
+## Guidelines
+The AAA (Arrange, Act, Assert) pattern is a common way of writing unit tests for a method under test.
+
+* The **Arrange** section of a unit test method initializes objects and sets the value of the data that is passed to the method under test.
+* The **Act** section invokes the method under test with the arranged parameters.
+* The **Assert** section verifies that the action of the method under test behaves as expected.
+
+Taken from https://docs.microsoft.com/en-us/visualstudio/test/unit-test-basics?view=vs-2019
+
+If you are finding you need to test a lot of private behavior, most likely you have a new 'class' hiding within the class you are trying to test, extract it and test it by its public interface.
+
+Taken from https://stackoverflow.com/questions/9122708/unit-testing-private-methods-in-c-sharp