6. Testing and running solutions

errors
1. syntax- error used in the programming language- e.g: missing braces, no semi-colon, missing parts of constructs
2. logical- caused by the mistakes in the design of the program, code will run but will not give the right results
3. run-time- happens while the program is running, syntax is fine but when run an error is found due to mistakes in the algorithm or an external reason- e.g.: out of memory, divide by 0...
testing
1. black box test data can be:
  1. NORMAL- very surely and completely within the range (should be accepted)- makes sure that the program performs properly,
  2. BORDERLINE- on the border of range (v. important)- most errors are when borderline data is not accepted,
  3. INVALID- outside the range (should be rejected), should check all data to make sure program works properly
2. testing strategies:
  1. BLACK BOX: inputs tested to see if they produce the outputs that should be, done by customers, all parts of test data is tested
    1. What is done: requirements and specifications of the system examined, data checked to see if expected outputs are git, test cases created and executed, outputs compared, defects fixed and retested
    2. Finds: incorrect/ missing functions, interface errors, data structure errors, performance errors, initialisation and termination
    3. Advantages: does not need to know coding, less bias (third party), test cases can be tested as soon as spec is produced
    4. Disadvantages: way program works is not considered, test cases are difficult to design, time consuming to test every input, white box has to still be carried out
  2. WHITE BOX: testers test each line of code for logic and accuracy, normally tests extremes, done manually or debugging software
    1. Advantages: helps optimize the code, can test effectively as it is easy to find the best data to use, tested by programmer so they know the program well
    2. Disadvantages: Uses specific programming knowledge, Only works if the programmer know what the program actually does, Does not account for errors that are created from omission
  3. ACCEPTANCE: done when the software is complete, programmer has to prove that the program fits all of the customers specification, can be done as alpha or beta testing
  4. ALPHA: done in the company where employees who did not produce software test it
    1. Advantages: uses both black box and white box testing, problems are sorted immediately
    2. Disadvantages: doesn't check reliability robustness and security, requires testing environment, software might not be complete so might still contain errors
  5. BETA: privileged customers test the software and give back constructive criticisms
    1. Advantages: checks reliability robustness and security, can be done anywhere, software virtually complete but might sill have bugs
    2. Disadvantages:uses only black box testing, problems implemented in future versions of software
dry runs(trace tables)
1. put each variable and track the value of each variable
debugging tools
1. translator diagnostics- points out if there are any errors in the code by saying which part of which line is wrong- error messages - syntax error
2. Break point- tell it to pause at a certain point in the code- can go through line by line after- can trace variables in a trace table- double click to add it- logical or run time
3. stepping- going through the code line by line- can do it at your speed- check variables- logical or run time
4. variable checks- trace tables- look at variables and their value at each point- can look at patterns to find errors- logical and run time error
purpose of an installation routine
1. Copy program from CD to computer
2. Copy any data files from the CD to computer
3. Copy and registered any library routines which are needed from CD to computer
4. Check for any dependencies
5. Check for space
6. Check for compatibility
7. Register the program in the computer
8. Enable the program to be uninstalled later
9. Initial user configuration is saved in a file
10. Provide an icon or shortcut so that the program can be run easily
11. Programs may need extracting from a compressed file

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6. Testing and running solutions

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