Tag Archives: QuviQ AB

  • Testing Eventual Consistency in Riak
    2012-05-28 Erlang Central

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    Riak is one of the new breed of no-SQL database management systems, which has begun to replace relational databases for some applications. Riak is a distributed key-value store, inspired by Amazon’s Dynamo, designed for applications where scalability, low latency and high availability are critical. Riak uses replication to provide fast access to data, even when multiple nodes or parts of the network fail. It supports concurrent access to the same data by multiple clients, even when the ...


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  • Certifying your car with Erlang
    2012-03-26 Erlang Central

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    Modern cars are full of software, with 50-100 processors and tens of millions of lines of code. Increasingly, this software is based on the AUTOSAR standard, drawn up by a consortium including Toyota, Ford, GM, and most of the world's other major car manufacturers. AUTOSAR defines the "basic software" which should run on each processor, providing a standardised environment enabling AUTOSAR applications to be distributed freely around the processors in the car. Such is the theory. In practice, ...


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  • QuickCheck for EUnit
    2012-03-02 Erlang Central

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    We are all used to writing EUnit test cases, but are they good enough? Are we missing some relevant unit tests in our test suite? With the bluefringe algorithm one can compute a state machine that describes the tests in the suite and additional tests that seems to hold as well. By using QuickCheck as an underlaying motor, one can then generate EUnit tests that improve your test suite. Together QuickCheck and bluefringe form a useful pair for those that want to learn writing QuickCheck stat ...


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  • Tutorial: QuickCheck Mini
    2011-10-31 Erlang Central

    Presentations

    QuickCheck support property based development. Instead of writing test cases for your applications, you write a one-pager with a QuickCheck property from which hundreds of test cases are generated automatically. QuickCheck simplifies failing cases to a minimal example on a test failure (so that fault diagnosis is quick and easy). QuickCheck enables developers to dramatically improve test coverage, and find obscure errors at an earlier stage, lowering costs and improving quality as a result. I ...


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  • Tutorial: Quickcheck for EUnit
    2011-10-31 Erlang Central

    Presentations

    Writing EUnit tests is more common than writing QuickCheck specifications, although QuickCheck specifications potentially explore far more scenarios than manually written unit tests. In particular for implementations that have side-effects, writing a good set of EUnit tests is often difficult and labour intensive. In this tutorial  we explain a mechanism to extract QuickCheck specifications from EUnit test suites. We use the QSM algorithm to infer state machines from sets of positive and neg ...


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  • Testing AUTOSAR components with QuickCheck
    2011-06-06 Erlang Central

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    The amount of software in a car is growing exponentially. This software has to be produced quickly, differentiate from the competition in functionality, multiplicity of features, and quality. There are several ingredients for enabling this, among them choosing the right technologies, improving the software process, and also being extremely thorough and efficient in testing. The automotive industry have standardized their components in the AUTOSAR standard. Each component has about 500 pages t ...


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  • How I found five lurking race conditions in mnesia with 200 lines of QuickCheck code
    2011-06-06 Erlang Central

    Presentations Videos

    Race conditions are among the worst kind of problem to debug: they tend to appear only rarely (and unrepeatably), often arise only in long running cases in production, and leave little evidence of what went wrong. Erlang is not immune to race conditions, despite its excellent support for concurrency, and they can give rise to rare intermittent failures in OTP libraries such as mnesia, the OTP database. Mnesia is known to fail "once every month or two" in production, and race conditions are one l ...


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  • Free QuickCheck for all
    2011-03-21 Erlang Central

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    On the face of it, property-based testing is a no-brainer: you write shorter, clearer test code, and in return test your system more thoroughly using thousands of generated tests. In practice, many developers are unsure where to start. How do you come up with good properties? How do you generate good test data? How do you evaluate the quality of your testing? In this talk, I’ll show how to overcome these difficulties, and give rules of thumb that can help you get started with property-based ...


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  • Testing automotive software with Erlang
    2010-11-17 Erlang Central

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    Modern cars are filled with software. The software for cars is normally written in C and the specifications are at least as bulky as those known from the telecommunication industry. Different from Erlang software, it has some hard real-time requirements, where tasks definitely need to meet certain deadlines. Nevertheless, it is beneficial to test this software by using Erlang as a test framework. We report on a project of testing an AUTOSAR component by using a combination of Erlang and Quick ...


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  • QuickCheck Mini
    2010-11-15 Erlang Central

    Presentations

    QuickCheck support property based development. Instead of writing test cases for your applications, you write a one-pager with a QuickCheck property from which hundreds of test cases are generated automatically. QuickCheck simplifies failing cases to a minimal example on a test failure (so that fault diagnosis is quick and easy). QuickCheck enables developers to dramatically improve test coverage, and find obscure errors at an earlier stage, lowering costs and improving quality as a result. I ...


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  • QuickSpec: Formal Specifications for Free!
    2010-06-07 Erlang Central

    Videos



    QuickSpec is a tool that takes an Erlang or Haskell API and guesses a formal specification for it! QuickSpec is mostly automatic: it "reverse-engineers" the specification by random testing of the API, and all the user need do is give the types of the functions to be tested as well as test data generators. QuickSpec only works on purely functional APIs, such as data structures, at the moment.This talk will show QuickSpec in action as well as the ideas behind it. ...


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  • Testing Asynchronous Behaviour in ejabberd with QuickCheck
    2010-06-07 Erlang Central

    Videos



    Ejabberd is an instant messaging server with lots of asynchronous behaviour. Such asynchronous behaviour is awkward to test, because of its inherent non-determinism. Variable event order and timing uncertainties can easily lead test cases to fail when they ought to pass, generating "false positives" that hinder testing. Yet coping with all possible event orderings and timings can make test cases hopelessly complex. When test cases are generated, these problems become even harder. In this talk ...


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