Testing Blog

TotT: Data Driven Traps!

Thursday, September 04, 2008
Share on Twitter Share on Facebook
Google
Labels: TotT

8 comments :

  1. UnknownSeptember 5, 2008 at 12:59:00 AM PDT

    A good post on the importance of maintainable tests!

    ReplyDelete
    Replies
      Reply
  2. Marlena ComptonSeptember 5, 2008 at 5:32:00 AM PDT

    This is an excellent post. It's too easy to use data the wrong way. Just had this discussion with someone yesterday, and I'm putting this on their desk.

    ReplyDelete
    Replies
      Reply
  3. Mark RoddySeptember 5, 2008 at 11:39:00 AM PDT

    I totally agree based on the example here. I wonder what you would propose for an alternative example. Where I work we keep 'models' in separate files from application source that uses them, and they all exist in a single directory. We have a rule that all model files must pass tests x, y, z ( I believer there's 12-15 of them). To accomplish this, there's a single test that iterates over each file in the directory and performs the same checks on each them.

    Note that this is a simplified explanation, but this does allow us to add new 'models' over time without having to add tests for each one.

    ReplyDelete
    Replies
      Reply
  4. MallikSeptember 8, 2008 at 1:00:00 AM PDT

    This comment has been removed by the author.

    ReplyDelete
    Replies
      Reply
  5. MallikSeptember 8, 2008 at 1:02:00 AM PDT

    How can google which claims best Testing team lose out on this basic security vulnerabilities?? Check out here

    ReplyDelete
    Replies
      Reply
  6. cuquiSeptember 8, 2008 at 11:11:00 AM PDT

    BUG : LOCALES[i] should be LOCALES[j]

    ReplyDelete
    Replies
      Reply
  7. UnknownOctober 26, 2008 at 10:27:00 PM PDT

    So... you've picked a test where the test logic is a single assert, and shown that if the data becomes complex and you don't have any diagnostic information, you end up with an unmaintainable test. Or if you shove together two different types of tests (a series of positive tests and one negative one that gets repeated if you stuff it in the loop), you're doing useless work. OK, fair enough. But you go from there to the conclusion that data-driven testing is bad, and I don't buy it.

    What about a situation where you're test logic is several lines? How large before the cutting and pasting is a more likely source of bugs than the data structure? Why not be sensible about defining the data and not mix positive and negative tests? Why not be sensible about error reporting and include an informative message with each line of data?

    Yes, unit tests in particular tend towards minimalist logic, and in such cases pulling out the data doesn't buy you much, and can obscure things as you add cruft to compensate for the code's generality. But just because you can construct a test case that is a poor fit for the data-driven methodology does not prove that that methodology is universally unsound.

    ReplyDelete
    Replies
      Reply
  8. David LonieJuly 19, 2013 at 6:33:00 AM PDT

    Maybe this is true with GTest, where rolling your own data-driven testing structures is necessary. Other testing frameworks build support for data-driven tests into the testing API in ways that are useful and easy to debug. I've had a lot of success writing, maintaining, and catching/fixing bugs using Qt's data-driven testing framework:

    http://qt-project.org/doc/qt-4.8/qtestlib-tutorial2.html

    When a test fails, it prints a human-readable description of the failing test case that is easy to correlate to the inputs, along with the expected and actual values that triggered the failure. Their implementation is easy to write, maintain, extend, and use. Don't knock the concept, improve the implementation ;-)

    ReplyDelete
    Replies
      Reply
Add comment
Load more...

The comments you read and contribute here belong only to the person who posted them. We reserve the right to remove off-topic comments.

  

Labels


  • TotT 104
  • GTAC 61
  • James Whittaker 42
  • Misko Hevery 32
  • Code Health 31
  • Anthony Vallone 27
  • Patrick Copeland 23
  • Jobs 18
  • Andrew Trenk 13
  • C++ 11
  • Patrik Höglund 8
  • JavaScript 7
  • Allen Hutchison 6
  • George Pirocanac 6
  • Zhanyong Wan 6
  • Harry Robinson 5
  • Java 5
  • Julian Harty 5
  • Adam Bender 4
  • Alberto Savoia 4
  • Ben Yu 4
  • Erik Kuefler 4
  • Philip Zembrod 4
  • Shyam Seshadri 4
  • Chrome 3
  • Dillon Bly 3
  • John Thomas 3
  • Lesley Katzen 3
  • Marc Kaplan 3
  • Markus Clermont 3
  • Max Kanat-Alexander 3
  • Sonal Shah 3
  • APIs 2
  • Abhishek Arya 2
  • Alan Myrvold 2
  • Alek Icev 2
  • Android 2
  • April Fools 2
  • Chaitali Narla 2
  • Chris Lewis 2
  • Chrome OS 2
  • Diego Salas 2
  • Dori Reuveni 2
  • Jason Arbon 2
  • Jochen Wuttke 2
  • Kostya Serebryany 2
  • Marc Eaddy 2
  • Marko Ivanković 2
  • Mobile 2
  • Oliver Chang 2
  • Simon Stewart 2
  • Stefan Kennedy 2
  • Test Flakiness 2
  • Titus Winters 2
  • Tony Voellm 2
  • WebRTC 2
  • Yiming Sun 2
  • Yvette Nameth 2
  • Zuri Kemp 2
  • Aaron Jacobs 1
  • Adam Porter 1
  • Adam Raider 1
  • Adel Saoud 1
  • Alan Faulkner 1
  • Alex Eagle 1
  • Amy Fu 1
  • Anantha Keesara 1
  • Antoine Picard 1
  • App Engine 1
  • Ari Shamash 1
  • Arif Sukoco 1
  • Benjamin Pick 1
  • Bob Nystrom 1
  • Bruce Leban 1
  • Carlos Arguelles 1
  • Carlos Israel Ortiz García 1
  • Cathal Weakliam 1
  • Christopher Semturs 1
  • Clay Murphy 1
  • Dagang Wei 1
  • Dan Maksimovich 1
  • Dan Shi 1
  • Dan Willemsen 1
  • Dave Chen 1
  • Dave Gladfelter 1
  • David Bendory 1
  • David Mandelberg 1
  • Derek Snyder 1
  • Diego Cavalcanti 1
  • Dmitry Vyukov 1
  • Eduardo Bravo Ortiz 1
  • Ekaterina Kamenskaya 1
  • Elliott Karpilovsky 1
  • Elliotte Rusty Harold 1
  • Espresso 1
  • Felipe Sodré 1
  • Francois Aube 1
  • Gene Volovich 1
  • Google+ 1
  • Goran Petrovic 1
  • Goranka Bjedov 1
  • Hank Duan 1
  • Havard Rast Blok 1
  • Hongfei Ding 1
  • Jason Elbaum 1
  • Jason Huggins 1
  • Jay Han 1
  • Jeff Hoy 1
  • Jeff Listfield 1
  • Jessica Tomechak 1
  • Jim Reardon 1
  • Joe Allan Muharsky 1
  • Joel Hynoski 1
  • John Micco 1
  • John Penix 1
  • Jonathan Rockway 1
  • Jonathan Velasquez 1
  • Josh Armour 1
  • Julie Ralph 1
  • Kai Kent 1
  • Kanu Tewary 1
  • Karin Lundberg 1
  • Kaue Silveira 1
  • Kevin Bourrillion 1
  • Kevin Graney 1
  • Kirkland 1
  • Kurt Alfred Kluever 1
  • Manjusha Parvathaneni 1
  • Marek Kiszkis 1
  • Marius Latinis 1
  • Mark Ivey 1
  • Mark Manley 1
  • Mark Striebeck 1
  • Matt Lowrie 1
  • Meredith Whittaker 1
  • Michael Bachman 1
  • Michael Klepikov 1
  • Mike Aizatsky 1
  • Mike Wacker 1
  • Mona El Mahdy 1
  • Noel Yap 1
  • Palak Bansal 1
  • Patricia Legaspi 1
  • Per Jacobsson 1
  • Peter Arrenbrecht 1
  • Peter Spragins 1
  • Phil Norman 1
  • Phil Rollet 1
  • Pooja Gupta 1
  • Project Showcase 1
  • Radoslav Vasilev 1
  • Rajat Dewan 1
  • Rajat Jain 1
  • Rich Martin 1
  • Richard Bustamante 1
  • Roshan Sembacuttiaratchy 1
  • Ruslan Khamitov 1
  • Sam Lee 1
  • Sean Jordan 1
  • Sebastian Dörner 1
  • Sharon Zhou 1
  • Shiva Garg 1
  • Siddartha Janga 1
  • Simran Basi 1
  • Stan Chan 1
  • Stephen Ng 1
  • Tejas Shah 1
  • Test Analytics 1
  • Test Engineer 1
  • Tim Lyakhovetskiy 1
  • Tom O'Neill 1
  • Vojta Jína 1
  • automation 1
  • dead code 1
  • iOS 1
  • mutation testing 1


Archive


  • ►  2025 (1)
    • ►  Jan (1)
  • ►  2024 (13)
    • ►  Dec (1)
    • ►  Oct (1)
    • ►  Sep (1)
    • ►  Aug (1)
    • ►  Jul (1)
    • ►  May (3)
    • ►  Apr (3)
    • ►  Mar (1)
    • ►  Feb (1)
  • ►  2023 (14)
    • ►  Dec (2)
    • ►  Nov (2)
    • ►  Oct (5)
    • ►  Sep (3)
    • ►  Aug (1)
    • ►  Apr (1)
  • ►  2022 (2)
    • ►  Feb (2)
  • ►  2021 (3)
    • ►  Jun (1)
    • ►  Apr (1)
    • ►  Mar (1)
  • ►  2020 (8)
    • ►  Dec (2)
    • ►  Nov (1)
    • ►  Oct (1)
    • ►  Aug (2)
    • ►  Jul (1)
    • ►  May (1)
  • ►  2019 (4)
    • ►  Dec (1)
    • ►  Nov (1)
    • ►  Jul (1)
    • ►  Jan (1)
  • ►  2018 (7)
    • ►  Nov (1)
    • ►  Sep (1)
    • ►  Jul (1)
    • ►  Jun (2)
    • ►  May (1)
    • ►  Feb (1)
  • ►  2017 (17)
    • ►  Dec (1)
    • ►  Nov (1)
    • ►  Oct (1)
    • ►  Sep (1)
    • ►  Aug (1)
    • ►  Jul (2)
    • ►  Jun (2)
    • ►  May (3)
    • ►  Apr (2)
    • ►  Feb (1)
    • ►  Jan (2)
  • ►  2016 (15)
    • ►  Dec (1)
    • ►  Nov (2)
    • ►  Oct (1)
    • ►  Sep (2)
    • ►  Aug (1)
    • ►  Jun (2)
    • ►  May (3)
    • ►  Apr (1)
    • ►  Mar (1)
    • ►  Feb (1)
  • ►  2015 (14)
    • ►  Dec (1)
    • ►  Nov (1)
    • ►  Oct (2)
    • ►  Aug (1)
    • ►  Jun (1)
    • ►  May (2)
    • ►  Apr (2)
    • ►  Mar (1)
    • ►  Feb (1)
    • ►  Jan (2)
  • ►  2014 (24)
    • ►  Dec (2)
    • ►  Nov (1)
    • ►  Oct (2)
    • ►  Sep (2)
    • ►  Aug (2)
    • ►  Jul (3)
    • ►  Jun (3)
    • ►  May (2)
    • ►  Apr (2)
    • ►  Mar (2)
    • ►  Feb (1)
    • ►  Jan (2)
  • ►  2013 (16)
    • ►  Dec (1)
    • ►  Nov (1)
    • ►  Oct (1)
    • ►  Aug (2)
    • ►  Jul (1)
    • ►  Jun (2)
    • ►  May (2)
    • ►  Apr (2)
    • ►  Mar (2)
    • ►  Jan (2)
  • ►  2012 (11)
    • ►  Dec (1)
    • ►  Nov (2)
    • ►  Oct (3)
    • ►  Sep (1)
    • ►  Aug (4)
  • ►  2011 (39)
    • ►  Nov (2)
    • ►  Oct (5)
    • ►  Sep (2)
    • ►  Aug (4)
    • ►  Jul (2)
    • ►  Jun (5)
    • ►  May (4)
    • ►  Apr (3)
    • ►  Mar (4)
    • ►  Feb (5)
    • ►  Jan (3)
  • ►  2010 (37)
    • ►  Dec (3)
    • ►  Nov (3)
    • ►  Oct (4)
    • ►  Sep (8)
    • ►  Aug (3)
    • ►  Jul (3)
    • ►  Jun (2)
    • ►  May (2)
    • ►  Apr (3)
    • ►  Mar (3)
    • ►  Feb (2)
    • ►  Jan (1)
  • ►  2009 (54)
    • ►  Dec (3)
    • ►  Nov (2)
    • ►  Oct (3)
    • ►  Sep (5)
    • ►  Aug (4)
    • ►  Jul (15)
    • ►  Jun (8)
    • ►  May (3)
    • ►  Apr (2)
    • ►  Feb (5)
    • ►  Jan (4)
  • ▼  2008 (75)
    • ►  Dec (6)
    • ►  Nov (8)
    • ►  Oct (9)
    • ▼  Sep (8)
      • by Miško Hevery We talked about how it i...
      • TotT: Mockin Ur Objectz
      • Presubmit And Performance
      • The Google Maps API Open Source Their Selenium Tes...
      • Where Have all the "new" Operators Gone?
      • Test first is fun!
      • My main() Method Is Better Than Yours
      • TotT: Data Driven Traps!
    • ►  Aug (9)
    • ►  Jul (9)
    • ►  Jun (6)
    • ►  May (6)
    • ►  Apr (4)
    • ►  Mar (4)
    • ►  Feb (4)
    • ►  Jan (2)
  • ►  2007 (41)
    • ►  Oct (6)
    • ►  Sep (5)
    • ►  Aug (3)
    • ►  Jul (2)
    • ►  Jun (2)
    • ►  May (2)
    • ►  Apr (7)
    • ►  Mar (5)
    • ►  Feb (5)
    • ►  Jan (4)

Feed

  • Google
  • Privacy
  • Terms