Programming Algorithms & Software Testing

Phases of Computer Program Development

1. Phase 1: Understand the problem
2. Phase 2: Design an algorithm to solve the problem
3. Phase 3: Write the program code in appropriate language based on the algorithm
4. Phase 4: Enter the program and save
5. Execute the program
6. Test the program, find errors and debug, then restest
7. Document and evaluate the program

Programming Structures

Sequential structure: Top-down execution
Decision structures: if/then/else
Iterative (Looping):

• while loop: continue looping as long as something is true
• repeat/until loop: continue looping until something is true
• for loop: loop a given number of times

• Repeat a set of instructions as a subtask of itself
• Repetion continues until:
  

  ➼ degenerative case, which is a termination condition, is met (degenerative case is also called a "base case")

Two classic programming/database problems

Sorting: Descending order/Ascending order

• Sorting numbers
• Sorting strings (in accordance with ASCII values)

In database:

• Filters: temporary search
• Queries: search criteria are saved so they don't have to be recreated

Sequential search: search from top to bottom or bottom to top, one item at a time
Binary search:

• Only works if data is SORTED first
• Start in the middle, then go to half of that, etc.

Two classic program goals:

Efficiency: Program takes minimal time and/or resources
Correctness: Program runs in expected ways and works for all expected conditions

Software testing and verification

Kinds of tests:

• Acceptance testing: Verifying whether the whole system works as intended
• Integration testing: Ensuring that software components or functions operate together
• Unit testing: Validating that each software unit performs as expected. A unit is the smallest testable component of an application
• Functional testing: Checking functions by emulating business scenarios, based on functional requirements. Black-box testing is a common way to verify functions
• Performance testing: Testing how the software performs under different workloads. Load testing, for example, is used to evaluate performance under real-life load conditions
• Stress testing: Testing how much strain the system can take before it fails. Considered to be a type of non-functional testing
• Usability testing: Validating how well a customer can use a system or web application to complete a task

• Architectural flaws
• Poor design decisions
• Invalid or incorrect funtionality
• Security vulnerabilities
• Scalability issues

• Continous testing
• Configuration management
• Service virtualization
• Defect or bug tracking
• Metrics and reporting