基于模型的测试

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[编辑] 基于模型的测试（Model-based testing）

基于模型的测试属于软件测试领域的一种测试方法。按照此方法，测试用例可以完全或部分的利用模型自动产生。以上所说的模型通常是指对被测系统（SUT,system under test）某些（通常是功能性的）方面的描述。

模型一般都是对被测系统（SUT,system under test）预期行为动作的抽象描述。 The test cases derived from this model are functional tests on the same level of abstraction as the model. 这些测试用例的集合就是我们平时所称的抽象测试套件（abstract test suite). 抽象测试套件不可以直接执行于需测试的系统，因为，他们不在同一抽象级别。因此，一个[[可执行的测试套件]]must be derived from the abstract test suite that can communicate with the system under test. This is done by mapping the abstract test cases to concrete test cases suitable for execution.

There are many different ways to "derive" tests from a model. Because testing is usually experimental and based on heuristics, there is no one best way to do this. It is common to consolidate all test derivation related design decisions into a package that is often known as "test requirements", "test purpose" or even "use case". This package can contain e.g. information about the part of the model that should be the focus for testing, or about the conditions where it is correct to stop testing (test stopping criteria).

测试套件(test suites)是由模型生成，而不是由源代码生成。因此，基于模型的测试又常常被当作黑盒测试的一种形式。但从某种层面来说, 这并不十分准确。毕竟，基于模型的测试是与源代码级的测试覆盖率，以及对代码的功能测试都有着很大的关系。

对于复杂的软件系统，基于模型的测试需要很大程度的提高才行.

[编辑] 模型

Especially in Model Driven Engineering or in OMG（Object Management Group）'s 模型驱动构架(model-driven architecture) the model is built before or parallel to the development process of the system under test. The model can also be constructed from the completed system. 目前，模型大多数使用手工创建。但同时，有很多使用自动化方式创建模型的尝试也在研究当中。建立新模型的一种重要方式是通过使用类似ATL的语言进行"模型转换"。

[编辑] 测试产生方法学

The effectiveness of model-based testing is primarily due to the potential for automation it offers. If the model is machine-readable and formal to the extent that it has a well-defined behavioral interpretation, test cases can in principle be derived mechanically.

Often the model is translated to or interpreted as a finite state automaton or a state transition system. This automaton represents the possible configurations of the system under test. To find test cases, the automaton is searched for executable paths. A possible execution path can serve as a test case. This method works if the model is deterministic or can be transformed into a deterministic one.

Depending on the complexity of the system under test and the corresponding model the number of paths can be very large, because of the huge amount of possible configurations of the system. For finding appropriate test cases, i.e. paths that refer to a certain requirement to proof, the search of the paths has to be guided. For the test case selection multiple techniques are applied.

[编辑] “证明法”产生测试用例

Theorem proving has been originally used for automated proving of logical formulas. For model-based testing approaches the system is modelled by a set of logical expressions (predicates) specifying the system's behavior. For selecting test cases the model is partitioned into equivalence classes over the valid interpretation of the set of the logical expressions describing the system under test. Each class is representing a certain system behavior and can therefore serve as a test case.

The simpliest partitioning is done by the disjunctive normal form approach. The logical expressions describing the system's behavior are transformed into the disjunctive normal form.

The classification tree-method provides a more sophisticated hierarchical partitioning. Also partitioning heuristics are used supporting the partitioning algorithms, e.g. heuristics based on boundary value analysis.

[编辑] Test case generation by constraint logic programming

Constraint programming can be used to select test cases satisfying specific constraints by solving a set of constraints over a set of variables. The system is described by the means of constraints. Solving the set of constraints can be done by boolean solvers (e.g. SAT-solvers based on the boolean satisfiability problem) or by numerical analysis, like the Gaussian elimination. A solution found by solving the set of constraints formulas can serve as a test cases for the corresponding system.

[编辑] 依靠检查模型产生测试用例

Originally model checking was developed as a technique to check if a property of a specification is valid in a model. We provide a model of the system under test and a property we want to test to the model checker. Within the procedure of proofing if this property is valid in the model the model checker detects witnesses and counterexamples. A witness is a path, where the property is satisfied, a counterexample is a path in the execution of the model, where the property is violated. This paths can again be used as test cases.

[编辑] Test case generation by symbolic execution

Symbolic execution is often used in frameworks for model-based testing. It can be a means in searching for execution traces in an abstract model. In principle the program execution is simulated using symbols for variables rather than actual values. Then the program can be executed in a symbolic way. Each execution path represents one possible program execution and can be used as a test case. For that, the symbols have to instantiated by assigning values to the symbols.

[编辑] 相关链接

• http://www.model-based-testing.org（英文）
• http://www.goldpractices.com/practices/mbt/index.php （关于基于模型测试的一个调查）（英文）
• http://www.mdqa.org/ (also http://www.modelbasedtesting.info/) （一个关于基于模型测试 以及 模型驱动质量保证的站点)(英文)

Tools (in alphabetical order)

• AsmL Test Tool can generate tests directly from an AsmL model
• ATD-Automated Test Designer is a model-based testing tool that generates automatically test cases, test data and test automation scripts from requirement specifications
• AutoFocus (in German) is a graphical tool for developing and modeling distributed systems with integrated testing facilities
• Conformiq Qtronic is a design model driven automatic on-the-fly testing tool employing UML and Java models
• Conformiq Test Generator is a tool that executes tests from UML state charts that represent testing strategies
• Leirios Test Generator is a model-based testing tool that generates tests automatically from UML 2.0 system specifications
• Lurette is an automated testing tool of reactive programs written in Lustre
• Reactis Tester is another model-based testing tool that focuses on control systems
• Spec Explorer is a model exploration and test suite generation tool from Microsoft that uses Spec#, C#, or AsmL to describe models
• TGV is a tool for the generation of conformance test suites for protocols
• TorX is also a prototype testing tool for conformance testing of reactive software

[编辑] 相关概念

• Model-driven architecture (MDA is an OMG Trademark)
• Model Driven Engineering (MDE is not an OMG Trademark)
• Model Integrated Computing (MIC)
• Generic Modeling Environment (GME)
• Domain Specific Language (DSL)
• Domain-specific modelling (DSM)
• Meta-modeling
• ATL
• VIATRA
• XMI
• OCL
• MOF
• Object-oriented analysis and design (OOAD)