Software development process model

1.1.1 Waterfall model

1.1.1.1 definition

Definition: A linear model is a type of model that occupies an important position in all models and is the basis for other models. Software development is performed once in each phase, in the order of linear models

Testing entry point: The testing phase is after the software is implemented and must allow enough time for testing activities after the code is completed, otherwise the testing will not be sufficient and many problems will be exposed later in the project

1.1.1.2 the pros and cons

Waterfall model Status: This is a classic model that provides a basic framework for software development. Advantages: 1) Clear division of phases 2) emphasis on planning and requirements analysis 3) Product development suitable for stable requirements disadvantages: 1) single process, irreversible 2) Late exposure of risks, less chance of correction 3) Testing is only one stage, lack of the idea of the whole process of testing 4) The division of each stage is completely fixed, resulting in a large number of documents between stages, greatly increasing the workload 5) Because the development model is linear, Users can only see the development results at the end of the whole process, thus increasing the risk of development. 6) Errors in the early stage may not be discovered until the testing stage of the later stage of development, resulting in serious consequences

1.1.1.3 improved

The linear thought of waterfall model is used to refine each stage, and the iterative thought is added between the stages of writing important concerns

1.1.1.4 Application Scenarios

bank
insurance
building
Traditional industry

1.1.2 Rapid prototyping model

1.1.2.1 Prototype stage

Rapid analysis
specifications
prototyping
The prototype
Run the prototype
Evaluation of the prototype
amendments

1.1.2.2 steps

step1

By building a rapid prototype, users can interact with the system, users can evaluate the prototype, and further refine the requirements of the software to be developed. By gradually adjusting the prototype to meet the requirements of users, developers can determine the real needs of users

step 2

On the basis of the first step, develop software products that users are satisfied with

1.1.2.3 pros and cons

Advantages The waterfall model overcomes the shortcomings, better meet the user needs and reduce the project development risk due to unclear software requirements, suitable for the development of software systems that can not define the requirements in advance
Disadvantages not suitable for large system development (suitable for small, flexible system development) requires a demonstration of the product prototype, thus may limit the developer’s innovation to a certain extent

1.1.2.4 Application Scenarios

WeChat
trill
Internet industry

1.1.3 Spiral model

1.1.3.1 model

Essentially, implementing a linear model more than once is a waste of time and is used less often in actual development

1.1.3.2 pros and cons

Advantages: The spiral model is largely a risk-driven approach, as risk assessment must be carried out before each stage and often before the cycle.
Disadvantages: Using spiral model requires rich experience and expertise in risk assessment. In the development of projects with high risks, if risks cannot be identified in time, it is bound to cause great losses. Too many iterations can increase development costs and delay commit times.

1.1.3.3 Application Scenarios

Large complex project

1.1.4 Differences between the three development models

1.2 V model

1.2.1 the pros and cons

Advantages:
- It includes both low-level testing (unit testing) and high-level testing (system testing);

Clearly identify the stages of development and testing;

Step by step refinement from top to bottom, clear division of labor at each stage, easy to control the overall project.

Disadvantages:
- As a result of the top-down order, the test work is done after the code, so that errors cannot be corrected in time;

In actual work, demand often changes, resulting in repeated execution of V model steps, large amount of rework and low flexibility.

1. 3 w model

1.3.1 the pros and cons

Advantages:
- Development takes place throughout the development cycle, and requirements and designs are tested as well;

– Earlier intervention test, can find the initial defects, low repair cost; – Work in stages to facilitate overall project management.

Disadvantages:
- Development and testing is still a linear relationship, requirements change and adjustment, is still not convenient;

– You can’t execute the W model without documentation; Higher technical requirements for project team members! – High administrative costs. – High communication costs

1.4 Comparison summary

V model applies to small and medium-sized enterprises,
W model is suitable for medium and large enterprises (due to high personnel requirements)

2. Classification of software testing

2.1 Functional Test

Write test cases

2.2 Automated Testing

python
java

2.3 Interface Test

postman

2.4 Performance Test

Let’s say 100 million people visit at the same time

3. Computer fundamentals

3.1 DOS command

		linux
dir	Displays the contents of the current directory	ls
ipconfig	Check the network card	ifconfig
cd	Open current path	cd
md	Creating a new directory
echo	The echo data > file
del	Delete the file
copy	Copy File The original path indicates the new path of the file
move	Move file contents to another file

4. Front-end knowledge

4.1 web3 large core

HTML tags – Heap boxes
CSS beautifies the page
Js behavior action

5. Back-end knowledge

5.1 cs/bs

5.1.1 cs

5.1.1.1 definition

Client-server Indicates the client-server

5.1.1.2 pros and cons

advantages

The client PC can handle some functions. After the client finishes processing, it can be handed over to the back end. The response speed is fast and the operation page is beautiful and safe

Disadvantages 1. Inconvenient installation 2. Poor compatibility, different systems require different version 3. Development and maintenance costs are high

5.2 bs architecture

5.2.1 definition

Browser-server – the server

5.2.2 the pros and cons

Advantages 1. Client 0 maintenance, only need a browser and network, can be accessed 2. Adding functions is simple, only need to add web pages can be completed 3. Users do not need to synchronize update 4. Development of simple
Disadvantages 1. Cross-browser compatibility 2. Slower response time 3. A weak

5.3 Differences between CS and BS

	cs	bs
The efficiency of	Cs is relatively efficient, and part of the data has been loaded into the system	Bs needs to load the latest data every time
Version update	Delete the old version and update the new version	Seamless upgrade
security	Cs is more secure, download, install, register, login	The browser
Development costs	Different systems require different developers and are costly	Low relative cost

5.4 File Format

5.4.1 XML

Data Transfer Case

<to>George</to> <from>John</from> <heading>Reminder</heading> <body>Don't forget the meeting! </body> </note>Copy the code

5.4.2 json

Such as: douban

6. Classification of software testing

6.1 Breakdown by test phase

Unit test: module test, which is the smallest program block
Integration testing: Testing modules together on the basis of unit testing
System testing: Testing the entire software system as a whole
Acceptance test:
- Alpha test: internal test version, in software developers internal communication, or released between loyal fans, under normal circumstances, are more bugs, ordinary users are not recommended to install
- Beta testing: the beta version developed by all users will be relatively Bug free
- γ test: release candidate for official release

6.2 Overwrite the source code based on whether to do so

6.2.1 Black Box Test

Focus only on business logic, input and output

6.2.2 White box Test

Ex. :

a = 1

b = 1

sum = a+b
print(sum)
Copy the code

Study the source code, observe the program structure

6.2.3 Grey Box Test

In between, gray box testing is used in the integration testing phase, focusing not only on input and output, but also on source code

Test concerns: 1. Test input 2. Test output 3

6.3 Partition based on running status

6.3.1 Static Test

Definition: does not run the program under test, but checks the correctness of the program by analyzing and examining the syntax, structure, procedures, and interfaces in the source code
White box TEST SQL script documents: requirements documents Various design documents, such as database design documents

6.3.2 Dynamic Test

Definition: Run the program under test, check whether the results are consistent with the expected results, analyze the efficiency, correctness and robustness (fault tolerance)
Test object source ===> run the system

6.4 Classification according to automation

6.4.1 Manual Test

Definition: Manually execute the test case procedure
Disadvantages: low efficiency and high repetitive work

6.4.2 Automated Testing

Definition: Use tools or code to help execute related test cases
Web automation
App automation

6.5 other

6.5.1 Smoke Test (Key)

Definition: For the current system to carry out the most basic function test, to ensure that the basic function and process can go through, verify whether the basic function of the software is achieved is testability

6.5.2 Regression Test (emphasis)

Definition: After the development changes the old code, the test retests to determine whether the code change introduces new errors or causes other code bugs to revert to the old function
Return to the principle of
- Required rounds: N-1 regression tests are required, depending on the complexity and size of the project, N versions
Disadvantages: Repetitive work is large and inefficient
Solution Automated testing: Automated regression testing

6.5.3 Random test

Definition: To check the performance and function of the software based on the experience of the tester
Point of attention: undertake retest to important function to did not cover get module to undertake test

6.5.4 Exploratory tests

Definition: Designing tests and executing tests simultaneously is a test thinking technique

Walk into the test takes you to understand the basics of testing 🧀 are 🈶 which