OSGi Versioning And Testing

OSGi Versioning and TestingChris AniszczykEclipseSourcehttp://aniszczyk.orgPaul VanderLeiBand XI International

Sample Application: ToastTelematics-On-A-STickSample from upcoming bookequinoxosgi.orgExample project in EclipseRTwiki.eclipse.org/Toast2OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0

get locationEmergencyMonitornotifyEmergencyServletsendHTTPGPSlogChannelLogToast: Emergency Scenario4OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0Airbag

Define Versioning“Software versioning is the process of assigning either unique version names or unique version numbers to unique states of computer software.”Versioning is relative though…6OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0

Versioning: User Perspective7OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0Versioning is a marketing thing…User’s don’t really care about versions…Users just want to know if the version of the software they are running is current…e.g., UbuntuFeisty Fawn – 7.04Gutsy Gibbon – 7.10Hardy Heron – 8.04

Versioning: Dev Perspective8OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0Version numbers are like dog tags*Primarily used in an event of emergency…*http://www.codinghorror.com/blog/archives/000793.html

OSGi VersionsDependencies are defined on the module and package levelImport-PackageRequire-BundleRanges allow for flexibilityImport-Package: org.easymock;version=[2.4.0,3.0.0)9OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0

OSGi Versioning Schememajor.minor.micro.qualifiermajor – An incompatible update; breaking APIminor – A backward compatible update; API stablemicro – A bug fix; no API changesqualifier – build date; lexigraphicVersions should encode compatibility* at the bundle and package level10OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0*http://wiki.eclipse.org/Version_Numbering

Bundle Versions in Eclipse11OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0Notice how the version numbers don’t necessarily match the 3.6 release?

Evolving API: GPS 1.012OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0Let’s evolve our GPS API…Evolving API: GPS 1.113OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0Toast on a plane… we add height…Evolving API: GPS 1.2?14OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0Management now wants an altimeter!Evolving API: GPS 2.015OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0We broke API, need to fix versions!Managing VersionsManaging versions is important and painfulAt Eclipse, we learned this quickly…Other projects eventually learn this…16OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0

Commons Collections !@#$18OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0“Commons collections 3.0 is binary compatible with version 2.1 and 2.0 except for certain methods on one class . As the release was a major version, this is permitted, however it was unintentional and an error… the chosen solution is to provide a work around by releasing v2.1.1 and v3.1.”http://commons.apache.org/collections/compatibility.html

Contracts are ImportantGood fences make for good neighbors!Binary compatibility* is important20OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0

ToolsBinary compatibility is importantMaintaining binary compatibility is complexEclipse puts API on an altar…Since Eclipse 3.4, Eclipse uses tools to manage and evolve API…21OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0*http://java.sun.com/docs/books/jls/second_edition/html/binaryComp.doc.html

PDE API ToolsAssists developers in API maintenance by reporting API defects such as binary incompatibilities, incorrect bundle version numbers and API usage.Let’s see an example…22OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0

Version Scheme Compliance24OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0Version number problems and quickfixes…Binary Compatibility Compliance25OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0Let’s unknowingly break API…Version Compliance Checking26OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0Never break API again unless you want to!API Comparison27OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0

API Comparison28OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0Understand API changes…API Usage Scan29OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0Understand who uses your API given a set of bundles

IssuesGetting proper version ranges correct is difficult if there’s no consistent semanticse.g., log4j caseNot all bundles are versioned properly in repositoriesTooling doesn’t cover packages yet…32OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0

SummaryOSGi versions encode compatibility!Don’t treat bundle versions like a marketing numberScope your version ranges properly33OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0

Testing: OverviewGood PracticesSample ApplicationUnit TestingSystem TestingRemaining Issues34OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0

Good Practices: TestabilityWrite your application as POJOs(plain-old-java-objects)No Service Trackers!Whiteboard Pattern is trickyPay attention to dependenciesUnit testing depends on getting this right35OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0

Good Practices: TestingUse JunitUse mock objects (EasyMock, jMock...)Minimize delaysNo human interactionDo TDD36OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0“…I think that developers who can’t cope with any level of TDD shouldn’t be coding at all…”

Unit Testing: OverviewTerminologyUnit under test (UUT)Test harnessTest each POJO on its own (no OSGi)Mock each dependency37OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0

get locationEmergencyMonitornotifyEmergencyServletsendHTTPGPSlogChannelLogToast: Emergency Scenario38OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0Airbag

UUTtest harnessUnit Testing: Example39OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0get locationEmergencyMonitornotifyEmergencyServletsendGPSMockGPSChannelMockChannelAirbagMockAirbagLog

Unit Testing: Test Case ProjectKeep the test case in a separate projectBut POJO is not visibleSolution:40OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0fragment bundle

System Testing: OverviewTest as much of system as possibleOSGi is presentTest full system flowTest bundles coming and going47OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0

UUTget locationEmergencyMonitornotifyEmergencyServletsendHTTPGPS?logChanneltest harnessLogMockLogSystem Testing: Example48OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0deployAirbagMockAirbagverifyTestCase

System Testing:Competing Programming ModelsPDE Junit test infrastructureuses EquinoxextensionsDeclarative Servicesuses OSGi services52OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0VS

System Testing:PDE Junit Test InfrastructureJunit instantiates the test case as usualsetup()testEmergency()Problem: no way to obtain:bundle contextmock airbagmock log53OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0

System Testing:Declarative ServicesInstantiates the test case as a componentDS dependency injectionsetAirbag(<our mock airbag>)setLog(<our mock log>)startup()Problem:This instance is never used by Junit!54OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0

System Testing: Test Case Code55OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0instances share theseDS invokes theseDS invokes theseDS invokes theseready to run test case

System Testing: Test Case Code56OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0wait until DS has activatednormalteststop GPS bundlestart GPS bundle

Remaining IssuesStill very trickyNot well-supported by PDE toolingValidation by logging is fragile58OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0

AvailabilityGet the slides: tinyurl.com/osgiVTGet the code: wiki.eclipse.org/ToastGet the book: equinoxosgi.org59OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0Questions?

Sample Application:Emergency Scenario60OSGi Versioning and Testing | © Copyright 2009 EclipseSource & Band XI International; made available under EPL v1.0EmergencyMonitorEmergencyServletGPSChannelAirbagLog

OSGi Versioning And Testing

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