This document introduces Nfluent, an ergonomic check library for .NET TDD that aims to make tests more fluent to write, read, and troubleshoot. It discusses how Nfluent provides auto-completion of available checks, clear error messages, and the ability to create custom check methods. The document also presents Nfluent's definition of done.

1. Nfluent

2. Agenda
• Definitions
• Why use Nfluent
• Create your own check method
• Nfluent Definition of Done (DoD)

3. What is Nfluent?
•
NFluent is an ergonomic check library which aims to fluent your .NET TDD
experience (based on simple Check.That() assertion statements)
•
An important part of the NFluent value is to allow a smooth writing of all the
checks.
•
NFluent by it’s nature, provides a really nice way to produce tests that make
sense
•
NFluent is not coupled to any .NET unit test framework. It is fully designed to
work in collaboration with your favorite one
•
NFluent is directly, but also freely, inspired by the Java FEST fluent
check/reflection library (http://fest.easytesting.org/).
•
It’s a simple nuget package
PM> Install-Package NFluent

4. Why useNfluent?
Simply because it makes your TDD more fluent
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5. NFluent aims your tests to be fluent to write
auto-completion:
With a super auto-completion 'dot' experience. Indeed, just type the
Check.That() followed by one of your object and a dot, and your IDE will show
you all the checks available for the type of the given object to verify. No more,
no less ( no auto completion flooding)
with Nfluent:
with assert method:
No hesitation about the kind of check that is possible and available regarding
my current System Under Test (SUT)
All you've got to remember is: Check.That, cause every check is then provided
via auto-completion
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6. Fluent to read
• very close to plain English, making it easier for non-technical people
to read test code
• your tests should also be your documentation and providing fluently
sentences near plain english instead of questionable asserts will
enhance that
• Other check libraries have not chosen the proper vocabulary (they
use Should() instead of Must())
With nfluent you'd rather rely on a stronger semantic for your checks
( NFluent's Check.That)
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7. fluent to troubleshoot
•
every failing check of the NFluent library throws an Exception with a crystalclear message status to ease your TDD experience
•
no need to set a breakpoint and to debug in order to be able to figure out
what went wrong.
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8. less error-prone
•
no more confusion about the order of the "expected" and "actual" values
you can find in the classical .NET unit tests frameworks
With assert method confusion with expected and actual
With Nfluent all is clear, just check.that:
•
all unit tests error message are reliable when tests are failing
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9. helpful to reverse engineer legacy code
• temporarily write an on-purpose failing assert on a
legacy method, so you can understand it and leverage
on the "ready-to-be-copied-and-paste-for-arrays-orcollections-initialization-purpose" NFluent assert failure
messages
• With check error message also well formated so that we
can easily instanciate arrays and collections type
initializers
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10. Red Green Refactor
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11. Create your own check method
•
All the secret of the NFluent extensions is on the ICheck<T> returned by the
Check.That<T>(T sut)
•
The idea is to provide an extension method on the ICheck<T> interface for
the T type you want to check.
With existing tests
A new test
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12. Demo
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13. Nfluent Definition of Done (DoD)
• No warning during the build (warn as error)
• No StyleCop warning
• 100% of test coverage for the NFluent project
– Test names should be clear enough to know what is in stakes
here
• The entire build (i.e. including all the unit tests execution) takes less
than a minute
• With (of course) all unit tests passed ;-)
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14. • https://github.com/tpierrain/NFluent
• http://www.codedistillers.com/rui/2013/11/26/nfluent-extensions/
• http://www.nuget.org/packages/NFluent/
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16. Find out more
•
On https://techblog.betclicgroup.com/

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