Unit Testing

Test Explorer

The Test Explorer allows browsing/finding, running, and adding unit tests to the active VBProject:

##QuickStart

The Refresh command synchronizes the test methods with the code in the IDE, but if test methods are added from within the Text Explorer then the new tests will appear automatically.

The Run menu makes running the tests as convenient as in the .NET versions of Visual Studio:

"Selected Tests" refer to the selection in the grid, not in the IDE.

The Add menu makes it easy to add new tests:

Adding a Test Module ensures the active VBProject has a reference to the add-in's type library, then adds a new standard code module with this content:

'@TestModule
Option Explicit
Private Assert As New Rubberduck.AssertClass

Adding a Test Method adds this template snippet at the end of the active test module:

'@TestMethod
Public Sub TestMethod1() 'TODO: Rename test
    On Error GoTo TestFail

    'Arrange

    'Act

    'Assert
    Assert.Inconclusive
    
TestExit:
    Exit Sub
TestFail:
    If Err.Number <> 0 Then
        Assert.Fail "Test raised an error: " & Err.Description
    End If
    Resume TestExit
End Sub

Adding a Test Method (expected error) adds this template snippet at the end of the active test module:

'@TestMethod
Public Sub TestMethod2() 'TODO: Rename test
    Const ExpectedError As Long = 0 'TODO: Change to expected error number
    On Error GoTo TestFail
    
    'Arrange

    'Act

    'Assert
    Assert.Fail "Expected error was not raised."
    
TestExit:
    Exit Sub
TestFail:
    Assert.AreEqual ExpectedError, Err.Number
    Resume TestExit
End Sub

The number at the end of the generated method name depends on the number of test methods in the test module.

The Assert Class

Note: equality checks are made per the equality rules of C#, which is more strict than VBA. Implicit type conversions are not allowed, and strings are case-sensitive; this is by design. A PermissiveAssertClass implementation is on the roadmap, to allow more VBA-like equality checks.

The AssertClass type exposes the following members.

Name	Description
AreEqual	Verifies that two specified objects are equal. The assertion fails if the objects are not equal.
AreNotEqual	Verifies that two specified objects are not equal. The assertion fails if the objects are equal.
AreNotSame	Verifies that two specified object variables refer to different objects. The assertion fails if they refer to the same object.
AreSame	Verifies that two specified object variables refer to the same object. The assertion fails if they refer to different objects.
Fail	Fails the assertion without checking any conditions.
Inconclusive	Indicates that the assertion cannot be verified.
IsFalse	Verifies that the specified condition is false. The assertion fails if the condition is true.
IsNothing	Verifies that the specified object is Nothing. The assertion fails if it is not Nothing.
IsNotNothing	Verifies that the specified object is not Nothing. The assertion fails if it is Nothing.
IsTrue	Verifies that the specified condition is true. The assertion fails if the condition is false.

##Discovery

Rubberduck will only attempt to find test methods in standard code modules (.bas) that have a '@TestModule marker comment.

Test methods must be Public, parameterless procedures (Sub). Public parameterless procedures in a test module will only be considered as test methods with either:

• Method name starting with Test, like TestMethod1
• Signature is immediately preceded by a '@TestMethod marker comment; this allows for more flexibility in naming.