1. software defects and their impact
1.1 What is a software bug
Software defects software product is the problem, and ultimately the performance of functions users need not fully realized, can not meet or can not meet all the needs of users.
Look inside the product, software defects are problems errors, errors of software product development or maintenance process exists.
From the outside, the software defect is a failure or breach of the system required to achieve a certain function.
Type software defects:
(1) the software does not implement the functions required by the product specification.
(2) An error has occurred Software product specifications should not be there.
(3) the software product features not mentioned in the specification.
(4) Unrealized software product specifications, although not explicitly mentioned features but that should be implemented.
(5) software difficult to understand, easy to use, run slowly - from the point of view testers - the end user will think bad.
1.2 software defect cases and impact
(1) the millennium bug (produce about 1974)
The date has not been stored century
(2) Patriot missile defense system (1991)
Calculating a clock made rounding, decimal to binary transfer, an infinite loop derivative
(3) Intel Pentium floating-point division defects (1994)
(4) the "Blaster" virus (2003)
(5) Nokia mobile phone platform defect (2008)
2. The emergence and development of software testing
1, resulting in software testing
Software trap Qi mainly produced:
(1) needs an error interpretation;
(2) user-defined error;
(3) needs a recording error;
(4) description errors;
(5) described coding error;
(6) program code bad;
(7) other error, such as: a data input and the like.
2, the development of software testing
(1) the initial stage (1957-1971 years)
(2) development phase (1972-1982)
(3) mature stage (1983 to date)
3, the cost of repairing software defects
Software development process is the use of software engineering methods, throughout the process, are likely to experience a wide variety of software defects. Over time, the development of software defect repair costs showed a rising multiples. If you find related loss of function, it can immediately make up, you can say that a small price to pay to be almost negligible. As early as during the analysis If you find a missing feature in the release, then the time to add a function, which is equivalent to re-develop the same, when the repair costs could be much higher, it said. So to be tested as soon as possible.
Software testing basic concepts 2
2.1 Definition of Software Testing
GJMyers software testing experts to define the next software testing as early as 1979: Software testing is to find errors and execution process for a program or system.
GJMyers three points associated with the test given to:
(1) the test is to prove that the procedure is wrong, instead of certification procedures without error;
(2) a good test it is found that the error has not found;
(3 ) a successful test is found wrong so far found no test.
1990, IEEE again given the definition of software testing:
(1) Run the system or components, or record the results observed under certain conditions, to make the evaluation of certain aspects of the system;
(2) an analysis software items to find the existing differences in the conditions and requirements and to evaluate the characteristics of the software item.
2.2 Software Test
1, test case definition software
IEEE Standard 610 (1990) definitions given:
a test case is a set of test inputs, expected results, and execution conditions set the aim to meet a specific target, such as a specific execution path of the program or verify compliance with a specific requirement.
2, test elements
the key issues of software test design can be summarized as 5W1H:
Why: Why test? Function, performance, availability, fault tolerance, security and other tests, to verify compliance with the relevant requirements.
What: What is measured? The test objects can be documentation, code, graphics and so on.
Where: Where measured? Test environment, including hardware, software, and network environment.
When: When measured? Prerequisites required test cases start as early as possible.
Which: what data? Test case design of a variety of data.
How: How to perform? What was the result? According to the steps to perform the test case design, the final results were compared to determine compliance. If the agreement to pass the test.
3, the basic principles of the design of test case
from two levels considered test cases:
(1) low-level - from a single test to see, to measure the normative description thereof, it is understood and maintainability strips.
(2) high level - a test to meet a goal or task test to measure a set of test cases of the structure, design ideas and so on coverage;
The basic principles of the test:
(1) a representative . Test cases can represent and cover all kinds of lawful or unlawful, set within the boundary or limit cross-border as well as input data, operation and environment.
(2) decidable . The test results of the implementation of the correctness can be determined. Each test case should have a corresponding expected results.
(3) reproducibility . For the result of performing the same test, the system should be the same, and the same test procedure may be performed repeatedly.
4, test case template
Software Testing Environment 2.3
1. What is the test environment
software testing environment is the software platform for the test run. Including a system of hardware, software and networks.
Can be expressed by a formula:
Test environment hardware = + + data + network software
2, construction and maintenance test environment
to establish (1) a room environment
(2) to establish the hardware environment
(3) to establish software environment
(4) to establish a network environment
(5) security measures embodiment
Requirements 2.4 software testers
1, the role and responsibilities of a software tester
role testers are mainly four categories:
(1) Test Manager: Test team is responsible for internal management and external staff, customers and the exchange of work, including schedule management, risk management, capital management , human resources management, communication management. As well as write, test summary reports and other tests are summarized in the plan. You must have the knowledge and skills of project managers.
(2) Test Designer: mainly based on various stages of design documentation software developers to design test cases produced each stage.
(3) test document Auditor: responsible for the pre-test, including all stages of analysis and design documents for review, such as: requirements specification, outline and detailed design manual.
(4) Test Engineer: Complete testing of test cases test phases designer.
2, the basic quality of software testers required
basic quality requirements are as follows:
(1) with basic theoretical knowledge of computer software testing
(2) familiar development tools and platforms
(3) master the use of testing tools
(4) good at learning, understanding and induction
(5) patient and meticulous, good working attitude