CTFL Module 03
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This document provides an overview of static testing techniques and how they differ from dynamic testing techniques. It defines static testing as testing that does not require executing the software, such as reviews, inspections and static analysis tools. Dynamic testing involves executing the software with test cases. The document then describes various static techniques like formal reviews, informal reviews, walkthroughs, technical reviews and inspections. It also discusses static and dynamic analysis tools. Finally, it covers cyclomatic complexity, which is a measure of how many independent paths exist in a program.
CTFL Module 03
- 1. CHAPTER 3 - Static techniques Based on ISTQB CTFL Syllabus Presented by : DavisThomas K
- 2. Syllabus
- 3. After completing this lesson, you will be able to understand: 1. Static techniques and test process 2. Review process 3. Static analysis by tools
- 4. K Level 3) Static testing: (K2) Reviews and theTest process (K2) Review Process (K2) Static analysis by tools (K2)
- 6. Static and DynamicTesting Static testing Dynamic testing Static testing does not require the actual execution of software. Dynamic testing involves testing the software by actually executing it. This type of testing can be used by the developer who wrote the code. Code reviews, inspections and walkthroughs are also used. Some of dynamic testing methodologies include unit testing, integration testing, system testing and acceptance testing. This is the verification portion of Verification andValidation Dynamic testing is the validation portion ofVerification andValidation. It may achieve 100% statement coverage in relatively short time. It achieves less than 50% statement coverage because it finds bugs only in part of codes those are actually executed. It can be done before compilation. It can take place only after executable are ready It usually takes shorter time. It may involve running several test cases, each of which may take longer than compilation.
- 7. Static and DynamicTesting Exam tip 1) Static testing is about prevention whereas dynamic testing is about cure. 2) Static testing is more cost-effective than dynamic testing. 3) Static testing tools provide greater marginal benefits as compare to dynamic testing. 4) Static testing gives comprehensive diagnostics for code than dynamic testing. 5) Dynamic testing finds fewer bugs as compare to static testing.
- 8. Static and DynamicTesting Exam tip 6) Dynamic testing usually takes longer time as compare to static testing as it test each case separately. 7) Static testing covers more areas than dynamic testing in shorter time. 8) Static testing is done before the code deployment whereas dynamic testing is after the code deployment. 9) Static testing is done in verification stage whereas dynamic testing is done in validation stage. 10) In static testing code is being examined without being executed whereas in dynamic testing, code is being executed and tested without necessarily being examined.
- 9. Static and DynamicTesting Exam tip 6) Dynamic testing usually takes longer time as compare to static testing as it test each case separately. 7) Static testing covers more areas than dynamic testing in shorter time. 8) Static testing is done before the code deployment whereas dynamic testing is after the code deployment. 9) Static testing is done in verification stage whereas dynamic testing is done in validation stage. 10) In static testing code is being examined without being executed whereas in dynamic testing, code is being executed and tested without necessarily being examined.
- 10. Static testing technique Formal review Formal reviews follow a formal process. It is well structured and regulated. A formal review process consists of six main steps: Planning Kick-off Preparation Review meeting Rework Follow-up
- 11. Static testing technique Formal review - Planning Planning: The first phase of the formal review is the Planning phase. In this phase there view process begins with a request for review by the author to the moderator (or inspection leader). The entry check is done to ensure that the reviewer’s time is not wasted on a document that is not ready for review. Hence the entry criteria for any document to go for the reviews are: The documents should not reveal a large number of major defects. The documents to be reviewed should be with line numbers. The documents should be cleaned up by running any automated checks that apply. The author should feel confident about the quality of the document so that he can join the review team with that document. Once, the document clear the entry check the moderator and author decides that which part of the document is to be reviewed
- 12. Static testing technique Formal review – Kick off meeting and preparation During the kick-off meeting the reviewers receive a short introduction on the objectives of the review and the documents Preparation: In this step the reviewers review the document individually using the related documents, procedures, rules and checklists provided. Each participant while reviewing individually identifies the defects, questions and comments according to their understanding of the document and role. After that all issues are recorded using a logging form.
- 13. Static testing technique Formal review – Review meeting Review meeting: The review meeting consists of three phases: Logging phase: In this phase the issues and the defects that have been identified during the preparation step are logged page by page. Discussion phase: If any issue needs discussion then the item is logged and then handled in the discussion phase. Decision phase: At the end of the meeting a decision on the document under review has to be made by the participants, sometimes based on formal exit criteria
- 14. Static testing technique Formal review – Rework / Follow-up Rework: In this step if the number of defects found per page exceeds the certain level then the document has to be reworked. Follow-up: In this step the moderator check to make sure that the author has taken action on all known defects.
- 15. Formal review Roles and Responsibilities During a review four types of participants take part. The moderator: a) Also known as review leader b) Performs entry check c) Follow-up on the rework d) Schedules the meeting e)Coaches other team f)Leads the possible discussion and stores the data that is collected The author: a) Illuminate the unclear areas and understand the defects found b)Basic goal should be to learn as much as possible with regard to improving the quality of the document.
- 16. Formal review Roles and Responsibilities The scribe: a) Scribe is a separate person to do the logging of the defects found during the review. The reviewers: a) Also known as checkers or inspectors b) Check any material for defects, mostly prior to the meeting c)The manager can also be involved in the review depending on his or her background. The managers: a) Manager decides on the execution of reviews b) Allocates time in project schedules and determines whether review process objectives have been met
- 17. Types of review Informal review Walkthrough Technical review Inspection
- 19. Types of review Informal review Informal reviews are applied many times during the early stages of the life cycle of the document. A two person team can conduct an informal review. In later stages these reviews often involve more people and a meeting. The goal is to keep the author and to improve the quality of the document. The most important thing to keep in mind about the informal reviews is that they are not documented.
- 20. Types of review Walkthrough It is not a formal process To present the documents both within and outside the software discipline in order to gather the information regarding the topic under documentation. To explain or do the knowledge transfer and evaluate the contents of the document To achieve a common understanding and to gather feedback. To examine and discuss the validity of the proposed solutions
- 21. Types of review Technical review It is less formal review It is led by the trained moderator but can also be led by a technical expert It is often performed as a peer review without management participation Defects are found by the experts (such as architects, designers, key users) who focus on the content of the document. In practice, technical reviews vary from quite informal to very formal
- 22. Types of review Inspection It is the most formal review type It is led by the trained moderators During inspection the documents are prepared and checked thoroughly by the reviewers before the meeting It involves peers to examine the product A separate preparation is carried out during which the product is examined and the defects are found The defects found are documented in a logging list or issue log A formal follow-up is carried out by the moderator applying exit criteria
- 23. Static test tools StaticTestTools:These tools do not involve actual input and output. Rather, they take a symbolic approach to testing, i.e. they do not test the actual execution of the software.These tools include the following: , 1) Flow analyzers:They ensure consistency in data flow from input to output. 2) Path tests:They find unused code and code with contradictions. 3) Coverage analyzers: It ensures that all logic paths are tested.
- 24. Dynamic test tools DynamicTestTools:These tools test the software system with 'live' data. Dynamic test tools include the following 1)Test driver: It inputs data into a module-under-test (MUT). 2)Test beds: It simultaneously displays source code along with the program under execution. 3) Emulators:The response facilities are used to emulate parts of the system not yet developed. 4) Mutation analyzers:The errors are deliberately 'fed' into the code in order to test fault tolerance of the system.
- 25. Cyclomatic Complexity Cyclomatic complexity is a software metric (measurement), used to indicate the complexity of a program The Cyclomatic complexity metric is based on the number of decisions in a program. It is important to testers because it provides an indication of the amount of testing (including reviews) necessary to practically avoid defects. Cyclomatic complexity = Number of decision statement + 1
- 26. Cyclomatic Complexity Draw a flow chart Below is a simple program as an example: IF A = 354 THEN IF B > C THEN A = B ELSE A = C ENDIF . ENDIF Print A
- 27. Cyclomatic complexity = No of binary decisions +1 There are 2 IF statements So , Cyclomatic complexity = 2+1 = 3
- 28. Q &A Lets try to answer few questions based on chapter 03
- 29. Question 1 Which is not a type of review? a.Walkthrough b. Inspection c. Informal review d. Management approval
- 30. Question 2 What statement about reviews is true? a. Inspections are led by a trained moderator, whereas technical reviews are not necessarily. b.Technical reviews are led by a trained leader, inspections are not. c. In a walkthrough, the author does not attend. d. Participants for a walkthrough always need to be thoroughly trained.
- 31. Question 3 What is the main difference between a walkthrough and an inspection? a. An inspection is led by the authors, whilst a walk through is led by a trained moderator. b. An inspection has a trained leader, whilst a walk through has no leader. c. Authors are not present during inspections, whilst they are during walkthroughs. d. A walkthrough is led by the author, whilst an inspection is led by a trained moderator.
- 32. Question 4 Which of the following statements about early test design are true and which are false? 1. Defects found during early test design are more expensive to fix. 2. Early test design can find defects. 3. Early test design can cause changes to the requirements. 4. Early test design takes more effort. a. 1 and 3 are true. 2 and 4 are false. b. 2 is true. 1, 3 and 4 are false. c. 2 and 3 are true. 1 and 4 are false. d. 2, 3 and 4 are true. 1 is false