This is the 10th day of my participation in the August More Text Challenge. For details, see “August More Text Challenge”.

preface

This series full text in 10 w +, the full text is the note in his own dry, soft test involves many basic computer, data structure and algorithm analysis and programming ideas, development process and so on, not only suitable for soft people learn, also suit to broaden their knowledge to learn, each article will be focused bold processing, especially easy to fault point, It is easy to remember wrong in exams. Please watch carefully! If you like this series, be sure to follow this column and leave a little like!

Chapter comb

• Structured analysis method is a kind of object-oriented data flow requirements analysis method, applicable to the analysis of large data processing system, is a simple, practical method, now has been widely used.

• The basic idea of structural analysis is to decompose from top to bottom. The analysis results of the SA method consist of a set of layered data flow diagrams (DFDS), a data dictionary, and a set of explanatory notes and supplementary materials.

• Basic components of DFD: External entity: Refers to a person or organization that exists outside the software system and is used to indicate where the data required by the system originates and where the data generated by the system resides.

• Processing: Describes the transformation between the input data stream and the output data stream, that is, the input data stream is processed to become the output data stream.

• Data store: Used to represent the data being stored. Each data store has a name.

• Data flow: consists of a set of fixed components of data, representing the flow of data.

Wrong topic integration

About coverage:

· Statement coverage means that enough test cases are selected so that each statement of the program under test is executed at least once when these test cases are run, and the coverage criteria cannot find errors in logical operations in the decision;

· Decision coverage < also known as branch coverage > refers to the selection of enough test cases so that all possible outcomes of each decision occur at least once when these test cases are run, but if the decision in the program is composed of several conditions, it may not be able to find the error of each condition;

· Conditional coverage refers to the selection of enough test cases so that when these test cases are run, all possible outcomes of each condition in the decision appear at least once, but may not cover all branches;

· Decision/condition coverage is such that all possible outcomes of each condition in a decision occur at least once, and all possible outcomes of each decision itself occur at least once;

· The modified condition decision coverage satisfies the condition and decision coverage, and each condition needs to be determined to affect the outcome of the included decision.

· Conditional combination coverage is such that all possible combinations of conditional outcomes in each decision occur at least once, and therefore all possible interpretations of the decision itself occur at least once, and also all possible outcomes of each condition occur at least once;

· Path override means that every possible path is executed at least once

• The goal of software testing is to find potential bugs and defects with minimal effort and time.
• The task of requirements analysis phase is to determine the software system function, usually using data flow diagram, ER, state transition diagram, data dictionary to describe the logical model of the system.
• Common coupling refers to the coupling between those modules that interact through a common data environment, which can be global variables or data structures, shared communication, common coverage of memory, and files on any storage medium.
• Warehouse style: multi-approach to problem solving, support for modification and maintainability, reuse of knowledge sources, support for fault tolerance and robustness. Warehouse style includes database system, blackboard system, hypertext system.

• The advantages of sandwich strategy: it is a combination of the advantages of top-down and bottom-up methods, so the main control and judgment points and the bottom module can be verified early. At the same time, it can develop from both ends to the middle, so the efficiency is higher.
• NS box diagram contains only five types of graph structure: order, selection, multi-branch selection, While cycle and Util cycle. The ability to clearly indicate the correspondence between complex conditional combinations and the actions to be performed

• Cohesion: communication cohesion > process cohesion > time cohesion > logic cohesion
• Bottom-up integration: Advantages – Early validation of underlying component behavior, work can initially be integrated in parallel, more efficient than top-down; Reduce pile workload; Supports fault isolation. Disadvantages – the development workload of the driver is large; Verification of higher levels is delayed and design errors are not detected in time.
• Maintainability should be considered at the design stage.
• Reverse engineering is based on the existing things and results, through analysis to deduce the specific implementation method. The purpose of reverse engineering is to make software maintainable.

• There are eight design principles for data flow diagrams: The principle of data conservation (for any process, all output data streams must be obtained directly from the input data stream of the process, or from the data that can be produced by the process), the principle of conservation of processing (for the same process, the input and output names must be different, Even if they have the same components), miracles, black holes, no data flow between external entities, no data flow between external entities and data stores, no data flow between data stores and data stores, the principle of balance between parent and subgraph, data flow is related to processing and must be processed.

• Data flow diagram modeling should follow a top-down, abstract to concrete principle