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Software Testability软件可测试性

Request From Quality

2009-03-03 2

No Agenda

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Impression Testability is defined as the degree to which a

system facilitates the establishment of test criteria and the performance of tests to determine whether those criteria have been met. (from IEEE 90)

DFT (Design For Test, Wikipedia), http://en.wikipedia.org/wiki/Design_For_Test

For software, testability is not only testable, but easy-to-test.

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Definition 简单的说，软件的可测试性就是一个计算机程序能够被测试的容易程度。

一般来说可测试性很好的软件必然是一个强内聚、弱耦合、接口明确、意图明晰的软件，而不具可测试性的软件往往具有过强的耦合和混乱的逻辑。

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Includes: Operability Visibility Resolvability Simplicity Intelligibility Control Stability

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Operability Excellent UX (don’t make me think) Smooth Interaction Less Error

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Visibility Accessible

Code (comments, changes)Design (changes)

State Standard Output (include error) Detailed Log Only one output for each input

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Resolvability Independent Modules Reduce coupling between modules

/layers Avoid UI inter-invocation

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Simplicity Function Structure Code

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Intelligibility Design Dependency Changes Document Guidance

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Control Standard Controls (recognizable by 3rd

party) Customized UI Elements

Naming standardRecognizable (name, type)UniquenessControllable (input, get, click)

Good practice: Forms Widgets

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Control (cont.) Testing purpose

Interface (method, url)Hook

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Stability Unfrequent changes Controllable changes Little impact on existing test Easy recovery

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Unit Test TDD(Test Driven Development) Less Arguments Short Method Simple Logic Clear Log Reduce Expensive Instantiation Weak Coupling

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Weak Coupling

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Causes for the lack of testability Dev concern functionality for customer not

tester Tester never aware demand functionality

/hooks help test Management support

Consequence: Software quality hurts, and test cost increase.

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为了测试它，我们需要了解它了解越多的信息，我们将测得更巧妙我们越是能控制它，测试越能被自动化和优化

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The End