Introducing
Your new presentation assistant.
Refine, enhance, and tailor your content, source relevant images, and edit visuals quicker than ever before.
Trending searches
Mocking .NET Without Hurting Its Feelings (MKE DOT NET 2017)
Mocking .NET Without Hurting Its Feelings
MKE DOT NET
Sept 9th, 2017
John M. Wright
john@wrightfully.com
@wright2tweet
www.wrightfully.com
© Copyright 2017 John M. Wright
wrightfully.com/mocktalk
class DependenciesHog
{
public string foo
{
get;
set;
}
private void bar(int x)
{
//I do stuff
}
public event BigEvent EventHorizon;
private void SpaceFiller()
{
while (true)
{
LookInteresting();
}
}
}
Why use a Mocking Framework?
Using Hand-Crafted, Artisanal Mocks
Brought to you in part by:
Need a dev job? Have a dev job to fill?
Stack Overflow's got you covered!
stackoverflowbusiness.com/talent
stackoverflow.com/jobs
mock
What can they do?
mock.VerifyAllExpectations();
mock.AssertWasCalled(x => x.MyMethod());
mock
vs
stub
vs
stub
A rose by any other name
would smell as sweet
work about the same
mock types
How do they do it?
Per Dev:
Per 5 Build Servers:
A Matter of Syntax
Code Examples (aka: What can you do?)
Unconstrained Code Examples
Generating Mocks
Example Test using a Mock
Code being tested
Using Moq Syntax
Typemock Syntax
Code being tested
MS Fakes Syntax
Unconstrained Frameworks:
Make Your Own Man-In-The-Middle Attack
Constrained Frameworks:
Limitations of Class Inheritance
Constrained Frameworks:
Class Inheritance On-Demand
internal types & members
Mocking Internal Types/Members
AssemblyInfo.cs
[assembly: InternalsVisibleTo("Your.TestAssembly")]
[assembly: InternalsVisibleTo("DynamicProxyGenAssembly2, PublicKey=0024000004800000940000000602000000240000525341310004000001000100c547cac37abd99c8db225ef2f6c8a3602f3b3606cc9891605d02baa56104f4cfc0734aa39b93bf7852f7d9266654753cc297e7d2edfe0bac1cdcf9f717241550e0a7b191195b7667bb4f64bcb8e2121380fd1d9d46ad2d92d2d15605093924cceaf74c4861eff62abf69b9291ed0a340e113be11e6a7d3113e92484cf7045cc7")]
sealed types
Generated Classes:
- Inherit / Extend Mocked Type
- Override virtual/abstract members
- Check for configured stubs/mocks
- Save details for later verification
- Take action based on configuration
Code Examples (aka: What can you do?)
ICorProfilerInfo::
SetILFunctionBody
Hijacked Code:
- Can change Behavior of ANY Type/Member
- Doesn't rely on inheritance
- Everything gets JIT'd, so anything can be mocked!
- Injected code will:
- Check for configured stubs/mocks
- Save details for later verification
- Take action based on configuration
Moq Syntax
RhinoMocks Syntax
NSubstitute Syntax
Typemock Syntax
MS Fakes Syntax
$ $ $
DateTime.Now
Throwing Exceptions
All that, plus:
- public
- internal
- methods
- properties
- events
- static
- sealed
- private
- .NET libs
- 3rd Party libs (Sharepoint)
Mocking Multiple Calls
Alternate Implementations
What can
I expect?
private members
Creating and Checking Expectations
JITCompilationStarted
dynamic
Unconstrained
Constrained
public types & members
My test
value
Stipulate A Return Value
methods, properties, events
partial
mock
- Open source
- No extra software needed
- Limited commercial support
- May require design compromises
- Proprietary (closed source)
- Some require profiler application / VS plugin
- Commercial support
class DatabaseConnection
{
}
substitute
More Info @
wrightfully.com/mocktalk
http://mimiandeunice.com/2011/07/19/expectations/
dynamic
mock
static types & members
shim
class AnotherOne
{
}
Using A Mocking Framework
Custom Mocks
File I/O
$$$
UI
$$
Integration
$
Unit Tests
FREE
158 members!
partial
Unconstrained
class DatabaseConnection
{
}
Great for testing "legacy" code.
Best fit for code written with testing in mind.
Class Being Tested
interfaces
fake
Tests
Return Value Based On Input
virtual / abstract members
strict
Constrained
Moq Syntax
RhinoMocks Syntax
NSubstitute Syntax
Typemock Syntax
MS Fakes Syntax
strict
mock
class DependenciesHog
{
public string foo
{
get;
set;
}
private void bar(int x)
{
//I do stuff
}
public event BigEvent EventHorizon;
private void SpaceFiller()
{
while (true)
{
LookInteresting();
}
}
}
Moq Syntax
RhinoMocks Syntax
NSubstitute Syntax
Typemock Syntax
MS Fakes Syntax