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research:jtransformer:tutorial:testing [2014/11/27 15:31] external edit
research:jtransformer:tutorial:testing [2018/05/09 01:59] (current)
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 +====== Testing ======
 +When writing analyses or transformations you often want to test 
 +  * that a particular piece of source code results in a particular set of facts, or 
 +  * that a factbase has a particular structure after a transformation.
 +For instance, assume you want to make sure that the source code
 +<Code lang-java>​
 +   class HelloWorld { 
 +     ​String message; ​
 +   }
 +is actually translated to the following PEFs
 +<Code lang-prolog>​
 +   ​classT(28446,​ 28445, '​HelloWorld',​ [], [28447, 28453]).
 +   ​fieldT(28453,​ 28446, 10005, message, null).
 +However, you cannot know the exact element IDs. You only want to express that 
 +  * the the inter-PEF links expressed by the IDs and  ​
 +  * the constants in the PEFs 
 +are as you expect. You can do this by keeping the constants but replacing the 
 +each concrete ID consistently by the same logic variable. Then the test condition ​
 +that you want to express can be written as a predicate:
 +<Code lang-prolog>​
 +  test(myTest) :- 
 + packageT(Package,''​),​
 + compilationUnitT(CompilationUnit,​Package,​_FileS,​[],​[Class]),​
 + classT(Class,​CompilationUnit,'​HelloWorld',​[],​[_SynteticConstructor,​Field]),​
 + fieldT(Field,​Class,​StringType,​message,​null),​
 + fully_qualified_name(StringType,​ '​java.lang.String'​ ). 
 +This predicate would suceed on any factbase that has the proper structure, including
 +the proper constants in the proper places. If anything is other than expected, the predicate ​
 +will fail. 
 +Unfortunately,​ we would not know why the predicate failed, that is, which of the individual ​
 +conditions caused the test to fail. In order to get this information,​ we can wrap each 
 +condition in a call of the assertion/1 predicate, which will throw an exception and output ​
 +a specific message if the wraped condition failed:
 +<Code lang-prolog>​
 +  test(myTest) :- 
 + assertion( packageT(Package,''​) ),
 + assertion( compilationUnitT(CompilationUnit,​Package,​_FileS,​[],​[Class]) ),
 + assertion( classT(Class,​CompilationUnit,'​HelloWorld',​[],​[_SynteticConstructor,​Field]) ),
 + assertion( fieldT(Field,​Class,​StringType,​message,​null) ),
 + assertion( fully_qualified_name(StringType,​ '​java.lang.String'​ ) ). 
 +Now the test framework will tell us exactly which was the first condition that failed. ​
research/jtransformer/tutorial/testing.txt · Last modified: 2018/05/09 01:59 (external edit)

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