Jenkins User Conference - Twitter4J, Jenkins and regression
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This document summarizes a presentation given by Yusuke Yamamoto at the 2011 Jenkins User Conference in San Francisco. Yamamoto discussed how he developed the open-source Twitter4J library using test-driven development and encountered a regression when the library's tests were not properly maintained. He emphasized the importance of having enough test coverage, carefully refactoring tests, and addressing failed tests to prevent regressions.
![Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf
Direct Cause of the Issue
bug in StringUtil – introduced in v2.1.5
– leads invalid OAuth signature in certain condition
public static String[] split(String str, String separator){
String[] returnValue;
int index;
if(-1 == str.indexOf(separator)){
returnValue = new String[0];
}else{
...
expected actual
split(“foo,bar”,”,”) {“foo”, “bar”} √ {“foo”, “bar”}
split(“foobar”,”,”) {“foobar”} L {}](https://image.slidesharecdn.com/jucyusukeyamamoto-111004034049-phpapp02/85/Jenkins-User-Conference-Twitter4J-Jenkins-and-regression-12-320.jpg)
Jenkins User Conference - Twitter4J, Jenkins and regression
- 1. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf Twitter4J, Jenkins and Regression Yusuke Yamamoto Twitter4J.org / Twitter, Inc. http://twitter4j.org/
- 2. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf Who Am I? 10+ years experience in Java Author of open-source tools including: – Samurai http://samuraism.jp/samurai/ – Twitter4J http://twitter4j.org/
- 3. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf What is Twitter4J Open-source library for the Twitter API Compatible with – Java 1.4.2+ – Android – Google App Engine Available since Jun 2007
- 4. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf Tools Powering Twitter4J Maven Central repo
- 5. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf The release flow release:perform git push origin master oss.sonatype.org service hook promote dev twitter4j.org github.com repo1.maven.org
- 6. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf Test-driven Development 1. Write a test case which fails 2. Implement and commit 3. Run test cases 4. J NO regression
- 7. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf The Timeline May 2007: Started Twitter4J project Mar 2009: Applied Hudson
- 8. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf The Timeline May 2007: Started Twitter4J project Mar 2009: Applied Hudson With Jenkins applied, your software should be regression free…
- 9. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf The Timeline May 2007: Started Twitter4J project Mar 2009: Applied Hudson Oct 2010: Critical regression found
- 10. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf The Timeline May 2007: Started Twitter4J project Mar 2009: Applied Hudson Oct 2010: Critical regression found The how and why
- 11. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf The Issue Version: Twitter4J 2.1.5 Symptom: certain method calls fail with 401 401:Authentication credentials were missing or incorrect.
- 12. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf Direct Cause of the Issue bug in StringUtil – introduced in v2.1.5 – leads invalid OAuth signature in certain condition public static String[] split(String str, String separator){ String[] returnValue; int index; if(-1 == str.indexOf(separator)){ returnValue = new String[0]; }else{ ... expected actual split(“foo,bar”,”,”) {“foo”, “bar”} √ {“foo”, “bar”} split(“foobar”,”,”) {“foobar”} L {}
- 13. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf Why StringUtil.split() String#split() - @since Java1.4 Found of a compatibility issue with CLDC – CLDC doesn’t support String#split() Caused by: java.lang.NoSuchMethodError: java.lang.String: method split (Ljava/lang/String;)[Ljava/lang/String; not found at twitter4j.conf.PropertyConfiguration.setFieldsWithTreePath(Ljava/ util/Properties;Ljava/lang/String;)V(PropertyConfiguration.java:196) at twitter4j.conf.PropertyConfiguration.<init>(Ljava/lang/String;)V (PropertyConfiguration.java:121)
- 14. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf General Cause of Software Regressions W/ test cases W/O test cases not enough test implementation coverage wrongly modified external resource test failure(s) ignored became incompatible
- 15. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf General Cause of Software Regressions W/ test cases W/O test cases not enough test implementation coverage wrongly modified external resource test failure(s) ignored became incompatible
- 16. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf General Cause of Software Regressions W/ test cases W/O test cases not enough test implementation coverage wrongly modified external resource test failure(s) ignored became incompatible
- 17. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf Ignoring Failed Test Cases Generally not recommended but Sometimes you need to, because – external resource not available or – test failure caused by a component managed by other committer
- 18. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf General Cause of Software Regressions W/ test cases W/O test cases not enough test implementation coverage wrongly modified external resource test failure(s) ignored became incompatible
- 19. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf General Cause of Software Regressions W/ test cases W/O test cases not enough test implementation coverage wrongly modified external resource test failure(s) ignored became incompatible test case wrongly modified
- 20. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf Ruined Tests with Basic Auth Deprecation TwitterTestUnit before refactoring: test base class Basic auth & OAuth BasicTest OAuthTest Basic auth OAuth after refactoring: OAuth only not recognized by Maven TwitterTestUnit
- 21. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf Ruined Tests with Basic Auth Deprecation TwitterTestUnit before refactoring: test base class Basic auth & OAuth BasicTest OAuthTest Basic auth OAuth after refactoring: OAuth only not recognized by Maven TwitterTestUnit
- 22. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf Lessons Learned - 1 check the Ages of failed tests
- 23. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf Lessons Learned - 2 be very careful when you refactor test cases make sure that – number of test cases doesn’t change many – code coverage doesn’t decrease smelly trend
- 24. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf Thank You To Our Sponsors Platinum Sponsor Gold Sponsor Silver Sponsor Bronze Sponsors Coming Soon: The CloudBees Newsletter for Jenkins ü Please complete the Jenkins survey to help us better serve the community (bonus: a chance to win an Apple TV!)
- 25. Jenkins User Conference San Francisco, Oct 2nd 2011 #jenkinsconf Who Am I?