Browse Prior Art Database

Method and System of Fault Localization for Dynamic Web Applications

IP.com Disclosure Number: IPCOM000202539D
Publication Date: 2010-Dec-21
Document File: 4 page(s) / 94K

Publishing Venue

The IP.com Prior Art Database

Abstract

A method and system of fault localization for dynamic web applications is disclosed. As such, the fault-localization is used to effectively localize faults in web applications. An extended domain for conditional and function-call statements may be used along with a source mapping for fault localization. In addition, test-generation strategies are proposed for producing test suites that may have maximal fault-localization effectiveness.

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Method and System of Fault Localization for Dynamic Web Applications

Disclosed is a method and system of fault localization for dynamic web applications.

A fault localization technique is described that is based on a source mapping and positional information obtained from an oracle. The oracle may be a function that determines whether a failure that occurs in an output may provide precise information about parts of the output that are associated with that failure. The oracle that determines whether a failure occurs in an output may often provide precise information about parts of the output that are associated with that failure. For instance, given a HyperText Markup Language (HTML) page, an HTML validator may typically report locations in the HTML file where the HTML is syntactically incorrect. Such information pertaining to locations in the HTML file may be used as a heuristic to localize faults in a program, provided it may be possible to determine portions of the program that produced the faulty portions of the output. In accordance with the method and system,
a code that produces the erroneous output may be scrutinized to identify causative fault. This may be formalized assuming the following two functions:

A function O (f ) returns output line numbers reported by oracle O for failure f ,

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and;

A function P (o ) returns a set of program fragments of a source program

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responsible for generating output line o .

Using these two functions, a suspiciousness rating Smap (l ) of a statement at line l for failure f may be defined as follows:

It may be observed that this is a binary rating, i.e. program parts are either highly suspicious, or not suspicious at all. The effectiveness of using the source mapping for fault localization may vary depending on the types of failures and applications. Typically, a HTML validator often produces good positional information. Therefore, the use of the source mapping may be combined with the use of statistical fault-localization methods.

The fault-localization technique based on the source mapping may be used to enhance the effectiveness of statistical algorithms by giving a higher rank to statements that are used by both the statistical method and the source-mapping technique. As such, a new suspiciousness rating Scomb (l ) is defined for the statement at line l as follows:

Hence, informally, the suspiciousness rating of 1.1 may be given to any statement that is identified as highly suspicious according to the source mapping. In addition, the suspiciousness rating of 1.1 may be given to any statement for which the original algorithm may indicate that the given line may be positively correlated with the fault. This may be indicated by a suspiciousness rating greater than 0.5.

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Thus, another enhancement technique is described that combines the fault-localization methods...