JML JUnit

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JML - JUnit
2
Goals

• Continuous unit testing (XP)
• Tie in with formal specifications
• Problems
• Writing unit test code is hard
• Duplication between
• Code for test oracles
• Formal specifications

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Specification as Test Oracle

• Write abstract pre- and postconditions
• Run test cases with assertion checking on
• Monitor assertion violations
• Why doesnt that work?

4
Tool Overview

• Users only
• Write specifications
• Supply test data of each type
• System automatically
• Constructs test cases from test data
• Assembles test cases into test suites
• Executes test suites
• Decides success or failure
• Reports results

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Usage

• jtest Person.java generates and compiles test
  classes for JML-JUnit testing
• Add test data to Person_JML_TestData.java and
  recompile
• jml-junit Person_JML_Test runs JUnit tests
• but tests must have been compiled with JML's
  runtime assertion checking compiler jmlc

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Test Suites are Cross Products

• For each receiver, test method
• For each method m(T1 arg1, T2 arg2) provide
• (x1, x2) x1in T1-TestData and x2 in
  T2-TestData
• Default is to use all data for all methods
• Filtered automatically by preconditions
• User can filter if desired