Fake your files - MemFs

•

1 like•1,016 views

Simon Courtois

My talk for Paris.rb on 2014-02-04.

Technology

Fake your ﬁles
Simon Courtois - @happynoff

class FileMaker
def create(path)
FileUtils.touch(path)
end
end

it "creates the given file" do
file_maker.create('thing.txt')
end

class FileMaker
def create(path)
FileUtils.touch(path)
end
end

it "creates the given file" do
file_maker.create('thing.txt')
expect(File.exists?(‘thing.txt’)).to be_true
end

class FileMaker
def create(path)
FileUtils.touch(path)
end
end

it "creates the given file" do
FileUtils.rm('thing.txt')
file_maker.create('thing.txt')
expect(File.exists?(‘thing.txt’)).to be_true
end

class FileMaker
def create(path)
FileUtils.touch(path)
end
end

it "creates the given file" do
expect(FileUtils).to receive(:touch)
.with(‘thing.txt')
.and_return(true)
file_maker.create('thing.txt')
end

class FileMaker
def create(path)
FileUtils.touch(path)
end
end

it "creates the given file" do
FakeFS do
file_maker.create('thing.txt')
expect(File.exists?('thing.txt')).to be_true
end
end

class FileMaker
def create(path)
FileUtils.touch(path, noop: true)
end
end

it "creates the given file" do
FakeFS do
file_maker.create('thing.txt')
expect(File.exists?('thing.txt')).to be_true
be_false
end
end

FakeFS
overwrites FileUtils and
ignores options

class FileMaker
def create(path)
FileUtils.touch(path, noop: true)
end
end

it "creates the given file" do
file_maker.create('thing.txt')
expect(File.exists?('thing.txt')).to be_false
end

class FileMaker
def create(path)
FileUtils.touch(path, noop: true)
end
end

it "creates the given file" do
MemFs.activate do
file_maker.create('thing.txt')
expect(File.exists?('thing.txt')).to be_false
end
end

MemFs
doesn’t overwrite FileUtils
only low-level classes

File.open('thing.txt') do |f|
f.puts 'hello'
end

!

File.read('thing.txt')
# => "hellon"

File.symlink('thing.txt', 'thing-link.txt')
File.symlink?('thing-link.txt')
# => true

File.stat('thing.txt').ctime
# => 2014-02-04 19:00:00 +0100
File.chmod(0777, 'thing.txt')

http://github.com/defunkt/fakefs
http://github.com/simonc/memfs

Similar to Fake your files - MemFs

DIWE - File handling with PHPRasan Samarasinghe

Description 1) Create a Lab2 folder for this project2.docxtheodorelove43763

Php fileskalyani66

File Handling in C ProgrammingRavindraSalunke3

Filesystems Lisbon 2018Frank de Jonge

File handling in C++Hitesh Kumar

Ch3(working with file)Chhom Karath

Web Development Course: PHP lecture 3Gheyath M. Othman

Advance C Programming UNIT 4-FILE HANDLING IN C.pdfsangeeta borde

Log into your netlab workstation then ssh to server.cnt1015.local wi.docxdesteinbrook

Having Fun Programming!Aaron Patterson

Automate the boring stuff with pythonDEEPAKSINGHBIST1

Java File I/OCanterbury HS

Filing system in PHPMudasir Syed

Linux Command Line - By Ranjan Raja Ranjan Raja

Java 7 Features and EnhancementsGagan Agrawal

Can someone put this code in a zip file. I tried running it last tim.pdffedosys

file_handling_in_c.pptyuvrajkeshri

General FunctionsBabuDevanandam

Linux commandsshekhar70

Similar to Fake your files - MemFs (20)

DIWE - File handling with PHP

Description 1) Create a Lab2 folder for this project2.docx

Php files

File Handling in C Programming

Filesystems Lisbon 2018

File handling in C++

Ch3(working with file)

Web Development Course: PHP lecture 3

Advance C Programming UNIT 4-FILE HANDLING IN C.pdf

Log into your netlab workstation then ssh to server.cnt1015.local wi.docx

Having Fun Programming!

Automate the boring stuff with python

Java File I/O

Filing system in PHP

Linux Command Line - By Ranjan Raja

Java 7 Features and Enhancements

Can someone put this code in a zip file. I tried running it last tim.pdf

file_handling_in_c.ppt

General Functions

Linux commands

Recently uploaded

Streamlining Python Development: A Guide to a Modern Project SetupFlorian Wilhelm

Dev Dives: Streamline document processing with UiPath Studio WebUiPathCommunity

"Subclassing and Composition – A Pythonic Tour of Trade-Offs", Hynek SchlawackFwdays

Advanced Computer Architecture – An IntroductionDilum Bandara

The Ultimate Guide to Choosing WordPress Pros and ConsPixlogix Infotech

Advanced Test Driven-Development @ php[tek] 2024Scott Keck-Warren

New from BookNet Canada for 2024: BNC CataList - Tech Forum 2024BookNet Canada

SIP trunking in Janus @ Kamailio World 2024Lorenzo Miniero

TrustArc Webinar - How to Build Consumer Trust Through Data PrivacyTrustArc

"Debugging python applications inside k8s environment", Andrii SoldatenkoFwdays

How to write a Business Continuity PlanDatabarracks

Artificial intelligence in cctv survelliance.pptxhariprasad279825

CloudStudio User manual (basic edition):comworks

Vertex AI Gemini Prompt Engineering TipsMiki Katsuragi

Merck Moving Beyond Passwords: FIDO Paris Seminar.pptxLoriGlavin3

E-Vehicle_Hacking_by_Parul Sharma_null_owasp.pptxnull - The Open Security Community

From Family Reminiscence to Scholarly Archive .Alan Dix

DevEX - reference for building teams, processes, and platformsSergiu Bodiu

H2O.ai CEO/Founder: Sri Ambati Keynote at Wells Fargo DaySri Ambati

"ML in Production",Oleksandr BaganFwdays

Recently uploaded (20)

Streamlining Python Development: A Guide to a Modern Project Setup

Dev Dives: Streamline document processing with UiPath Studio Web

"Subclassing and Composition – A Pythonic Tour of Trade-Offs", Hynek Schlawack

Advanced Computer Architecture – An Introduction

The Ultimate Guide to Choosing WordPress Pros and Cons

Advanced Test Driven-Development @ php[tek] 2024

New from BookNet Canada for 2024: BNC CataList - Tech Forum 2024

SIP trunking in Janus @ Kamailio World 2024

TrustArc Webinar - How to Build Consumer Trust Through Data Privacy

"Debugging python applications inside k8s environment", Andrii Soldatenko

How to write a Business Continuity Plan

Artificial intelligence in cctv survelliance.pptx

CloudStudio User manual (basic edition):

Vertex AI Gemini Prompt Engineering Tips

Merck Moving Beyond Passwords: FIDO Paris Seminar.pptx

E-Vehicle_Hacking_by_Parul Sharma_null_owasp.pptx

From Family Reminiscence to Scholarly Archive .

DevEX - reference for building teams, processes, and platforms

H2O.ai CEO/Founder: Sri Ambati Keynote at Wells Fargo Day

"ML in Production",Oleksandr Bagan

Fake your files - MemFs

1. Fake your ﬁles Simon Courtois - @happynoff

2. How to test ﬁles manipulation ?

3. class FileMaker def create(path) FileUtils.touch(path) end end it "creates the given file" do file_maker.create('thing.txt') end

4. class FileMaker def create(path) FileUtils.touch(path) end end it "creates the given file" do file_maker.create('thing.txt') expect(File.exists?(‘thing.txt’)).to be_true end

5. class FileMaker def create(path) FileUtils.touch(path) end end it "creates the given file" do FileUtils.rm('thing.txt') file_maker.create('thing.txt') expect(File.exists?(‘thing.txt’)).to be_true end

6. Read-only ﬁle system ?

7. class FileMaker def create(path) FileUtils.touch(path) end end it "creates the given file" do file_maker.create('thing.txt') end

8. class FileMaker def create(path) FileUtils.touch(path) end end it "creates the given file" do expect(FileUtils).to receive(:touch) .with(‘thing.txt') .and_return(true) file_maker.create('thing.txt') end

9. Boooh! Test behavior not implementation

10. Enters a solution FakeFS

11. class FileMaker def create(path) FileUtils.touch(path) end end it "creates the given file" do file_maker.create('thing.txt') expect(File.exists?('thing.txt')).to be_true end

12. class FileMaker def create(path) FileUtils.touch(path) end end it "creates the given file" do FakeFS do file_maker.create('thing.txt') expect(File.exists?('thing.txt')).to be_true end end

13. class FileMaker def create(path) FileUtils.touch(path, noop: true) end end it "creates the given file" do FakeFS do file_maker.create('thing.txt') expect(File.exists?('thing.txt')).to be_true be_false end end

14. BOOM! That’s a red dot

15. FakeFS overwrites FileUtils and ignores options

16. Try MemFS

17. class FileMaker def create(path) FileUtils.touch(path, noop: true) end end it "creates the given file" do file_maker.create('thing.txt') expect(File.exists?('thing.txt')).to be_false end

18. class FileMaker def create(path) FileUtils.touch(path, noop: true) end end it "creates the given file" do MemFs.activate do file_maker.create('thing.txt') expect(File.exists?('thing.txt')).to be_false end end

19. MemFs doesn’t overwrite FileUtils only low-level classes

20. File.open('thing.txt') do |f| f.puts 'hello' end ! File.read('thing.txt') # => "hellon" File.symlink('thing.txt', 'thing-link.txt') File.symlink?('thing-link.txt') # => true File.stat('thing.txt').ctime # => 2014-02-04 19:00:00 +0100 File.chmod(0777, 'thing.txt')

21. Some resources

22. http://github.com/defunkt/fakefs http://github.com/simonc/memfs

23. Questions ?

24. Thank you Simon Courtois - @happynoff

Fake your files - MemFs

Recommended

Recommended

More Related Content

Similar to Fake your files - MemFs

Similar to Fake your files - MemFs (20)

More from Simon Courtois

More from Simon Courtois (16)

Recently uploaded

Recently uploaded (20)

Fake your files - MemFs