Integrate the Microsoft Unit Testing Framework into your Visual Studio 2010 projects. Learn the fundamentals of the Microsoft.VisualStudio.TestTools.UnitTesting namespace. Explore the tools for running and debugging your unit tests. Discuss general best practices for writing unit tests. Examples will be presented in C#.

1. Using Visual Studio 2010
By Karen Gayda

2.  The test project is created by selecting “New
Project” from the File Menu.
 Expand Visual C# from the tree view on the
left-hand side of the dialog.
 Select “Test” from the list of options.
 In the center pane, select “Test Project”.
 Give the project a name and add it to your
application’s solution.

4.  Contains special classes designated by the
[TestClass] attribute which are intended to run
groups of tests.
 Generally speaking, each class in the application
project will have a corresponding class in the unit
test project.
 Some classes, such as UI classes, may not be tested
by the Unit Test class for UI interactivity. This is
tested with a macro-style test class type called a
Coded UI Test.
 Non-UI methods/properties of a UI class can still
be tested with a standard Unit Test class.

5.  Must have at least one test class in project.
 Project may have test data files for use by the
unit tests.
 Project may have utility/helper classes for
common functionality used by test classes and
test methods.
 Project may use configuration files to setup
state or provide environment information to
the tests.

7.  Microsoft.VisualStudio.TestTools.UnitTesting
namespace:
 The namespace has many classes to help you with your
unit tests including:
 Assert classes that you can use to verify conditions in unit
tests
 Initialization and cleanup attributes to run code before or
after unit tests run to ensure a specific beginning and
ending state
 The ExpectedException attribute to verify that a certain
type of exception is thrown during unit test execution
 The TestContext class which stores information that is
provided to unit tests such as data connection for data-
driven tests and information that is required to run unit
tests for ASP.NET Web Services

8.  TestClass attribute:
 When you create a unit test, the TestClass attribute is
included in the test file to indicate that this particular
class may contain methods marked with the
[TestMethod()] attribute. Without the TestClass
attribute, the test methods are ignored.
 A test class can inherit methods from another test
class that is in the same assembly. This means that
you can create test methods in a base test class and
then use those methods in derived test classes.

9.  TestContext - When you create unit tests, a
class private variable called
testContextInstance is included for each test
class. It is of type TestContext.
 The properties of the TestContext class store
information about the currently running test
class.

11.  ClassInitialize method
 Designated by the [ClassInitialize()] attribute.
 Used to setup anything needed by all the test
methods that will be run in the class. Examples of
this would be to create test databases, to create
tables, to copy test files, etc.
 Takes TestContext variable as parameter.
 One class initialization method per unit test class.

13.  ClassCleanUp method
 Designated by the [ClassCleanUp()] attribute.
 Used to cleanup artifacts of the test class for the test
run.
 Usually used to delete data, files, tables or databases
created by the class.
 One class cleanup method per test class.

15.  TestInitialize method
 Designated by the [TestInitialize()] attribut.e
 Method that runs before the execution of every test
in the class.
 Used to manage resources shared by the test
methods in the class.
 Used to setup test environment to an
initialized/known state prior to a test executing.
 One test initialize method per unit test class.

16.  TestCleanUp method
 Designated by the [TestCleanUp()] attribute
 Method runs after the execution of every test method
in the unit test class.
 Used to return the test environment to a known state
or clean up the artifacts created by a test.
 One test clean up method per unit test class.

17.  Designated by the [TestMethod] attribute.
 1 – n test methods per Unit Test class.
 1 method per major application requirement.
 1 method per public property/method/web
method as well (in most cases).
 A test method should test a single requirement
only.
 A test method should be atomic.

18.  IMPORTANT: Test methods must run
independently of one another!!!
 Test methods can run in any order, therefore
their operation cannot rely on state set by other
test methods.
 Test methods expecting any state or
environment setup should always have that set
by ClassInitialze or TestInitialize.
 It is not recommended that any state be setup
in the test method itself. Avoid doing so
whenever possible.

19.  Test method names should clearly indicate the
purpose of the test.
 For tests that test a public property/class
method/web method, use the name with the
word Test appended. An example of this
would be “ConnectionStringTest”.
 For tests that test a specific requirement, use a
clear requirement descriptor with the word
Test appended to the end. An example of this
would be “AllFilesProcessedTest”.

22.  Tests are deterministic.
 For a given environment state and known input
value(s), an expected result is the outcome of an
assertion.
 Hard-coded, expected values are normal/acceptable.
 Use the Assert class to check for various expected
conditions/state such as equality, inequality, Boolean
value, etc.
 Use the ExpectedException attribute of the test method
to insure that a specific exception is thrown if the
application should throw it for expected errors.
 If anyAssert method fails within a test, the test result
will indicate failure.
 Unhandled exceptions are treated as failures

23.  Test methods can have information about resources
they should use passed to them via attributes.
 The [DeploymentItem] attribute is used to specify
deployment items such as a file or a directory to be
used by a specific test.
 The [DeploymentItem] can also be applied to an entire
test class.
 There can be multiple deployment items specified for a
method or class.
 The [TestProperty] attribute is used to pass general
name/value pair data to a test.
 Test methods can have multiple test property attributes
specified.

24.  Best practice to have a good comment header for
each test method to clearly indicate what is being
tested.
 Should include the following:
Purpose: Short description of aspect of application being
tested.
Prerequisites: Assumptions being made before test can run
such as a database with certain data exists and is accessible to
the test project.
Test Data: Data being used and list of possible values or
ranges.
Steps: List of steps in test.
Remarks: Any pertinent information about test not covered
elsewhere but important to note.

25.  Usually created manually in test class by
developer.
 Skeleton tests can be generated by Visual
Studio for existing code.
 Generated tests can be created only for
properties/methods in existing code classes or
interfaces.
 Tests for specific requirements must be coded
manually.

26.  There are several ways to add tests to a test
project.
 To add a standard unit test class to your
project, go to the “Test” main menu option of
the VS 2010 IDE and select “New Test”
 Select the “Unit Test” item from the dialog box.
(The other test types available in VS 2010 are
not covered in this presentation).
 Give your test class a descriptive name and
click OK.

29.  To add your own unit tests to class, add public
void, parameterless methods decorated with
the test method attribute.
 Any method decorated with the [TestMethod]
attribute is considered a test by the unit testing
framework if it is contained within a test class.
 Uncomment the initialize/cleanup methods in
the region “Additional Test Attributes” if you
wish to use and customize them for your test
class.

30.  To generate tests from existing code, use the
Unit Test Wizard.
 From the “Test” main menu option of the VS
2010 IDE, select “New Test”.
 Select the “Unit Test Wizard” option.
 Select your unit test project from dropdown
list.
 Click OK to run the wizard.

32.  Expand the namespaces for your application
assembly in the tree view on the wizard.
 Expand the classes in the tree view to view the
individual proprties/methods of the classes.
 Select the classes and/or methods for which you
would like to generate unit tests.
 Click the settings button if you would like to
modify the default code generation settings.
 Click the Add Assembly button if you want to
generate tests from an additional assembly.
 Click OK to generate skeleton tests.

34.  Additional tests are easily added to existing
test class from application project.
 Right-clicking from within your application
class method gives context menu option to
“Create unit test”.
 Wizard automatically selects current method in
application (where cursor is positioned) and
chooses the same target class in the test project
as existing test methods for application class.

35.  The Test List Editor window is the easiest way
to manually run tests from the Visual Studio
2010 IDE.
 They can also be run from the command line in
an automated fashion, from the Microsoft Test
Manager application (both not covered in this
presentation), from the Test Results window of
the VS2010 IDE and from the Test View
window of the VS 2010 IDE.

36.  From the “Test” main menu option of the VS
2010 IDE, select “Windows”
 Choose the “Test List Editor” option
 The test list editor window gives you the
ability to group, run and debug your tests and
then view the results of the test run’s execution.

38.  Test results are displayed in the Test Results
window.
 This window is automatically displayed by the
Test List Editor when your test run completes
 All tests have a green “Passed” icon by them if
the tests executed correctly
 Any test with a red “Failed” icon should be
debugged to determine the reason for failure.

40.  Test result window displays a summary of all
of the test results.
 Clicking an individual result in the results grid
will open the results detail window and
display more detailed information about the
outcome of the selected test.
 Test Result Detail window provides detail
error information if a test fails.

42.  Each test run creates a log of the results of the
test run execution.
 Visual Studio will save the last 25 test runs by
default.
 Different test runs can be viewed in the Test
Results window.
 Test Results window will load most recent run
by default.
 Select run name from dropdown at top of test
results window to view other than most recent
test run.

43.  Unit tests help with regression testing so that you
may determine if new requirements/code changes
have broken existing functionality in the code.
 The VS 2010 test framework includes a feature
called Test Impact Analysis which helps to
streamline regression testing.
 You can use Test Impact Analysis to record a
baseline after initial unit test development.
 From then on, Test Impact Analysis will keep track
of what tests need to be run after code changes to
insure proper regression testing without running
all of the tests.

44.  Visual Studio 2010 testing framework makes it
easy to create and run unit tests for your Visual
Studio 2010 projects.
 Good unit tests must follow industry standard
best practices.
 Visual Studio does not impose any restrictions
on what you put in your test.
 It is incumbent on the unit test creator to write
good tests.

45.  http://msdn.microsoft.com/en-
us/library/dd264975.aspx
 http://msdn.microsoft.com/en-
us/library/ms182409
 http://blog.stevensanderson.com/2009/08/24/wr
iting-great-unit-tests-best-and-worst-practises/
 http://en.wikipedia.org/wiki/Unit_testing

46.  http://www.softwaretestingstuff.com/2010/09/u
nit-testing-best-practices-techniques.html
 http://www.amazon.com/dp/0321146530/?tag=s
tackoverfl08-20
 http://msdn.microsoft.com/en-
us/magazine/cc163665.aspx
 http://www.codeproject.com/Articles/10870/Ne
w-Version-Of-Rhino-Mocks

47.  http://weblogs.asp.net/adilakhter/archive/2008/
05/04/more-on-unit-testing-testcontext.aspx
 http://www.c-
sharpcorner.com/uploadfile/dommym/a-test-
driven-development-tutorial-in-C-Sharp-4-0/
 http://msdn.microsoft.com/en-
us/vstudio/ff718185.aspx
 http://www.simple-talk.com/sql/t-sql-
programming/close-these-loopholes---reproduce-
database-errors/