Simple CLI menu of a user registry/customer database.
Users are able to perform basic CRUD (Create, Read, Update, Delete) functionality.

1.0 Software Requirements Specifications

FR 1: Feature One Displaying customer information

FR 1.1: Feature One Expectation/Restraint Upon selecting the "list all customers" option, users are able to view a list of saved customers. Passable for a short list, but once the list grows, useability will suffer, so that is something for future consideration.

FR 2: Feature Two Updating customer information

FR 2.1: Feature Two Expectation/Restraint Upon selecting the "update existing customer" option, users will be able to edit customer details. There being only three fields at the moment makes it manageable, but for a full-fledged system, doing so on a CLI might prove cumbersome.

FR 3: Feature Three Data persistence

FR 3.1: Since there is a need for customer details to be stored, data persistence is enabled.
Just like with the first two points, a simple json file would suffice for now. Once it grows beyond the scope of this project, alternative solutions might have to be explored.

2.0 Software Design Being a CLI application, everything is text-based so that might not be for everyone. On the other hand, it runs lean without complex requirements.

2.1 UI/UX Design

Menu mock-up:

Final product:

When an option is selected:

2.2 Security Considerations

Since it was beyond the scope of this project, user login was not implemented. That would be the first step to improve upon moving forward. Simple validation was also added to sanitize user input and provide a smooth user experience. Tightening that up would also be another point of improvement.

3.0 Testing

3.1 Unit Tests

3.11 Unit Test One
Testing validation for adding a new entry.

Function Tested: Add new customer
Name of Test (what to test for): input validation

Outcome 1
Input: "123" into customer name field
Expected Output: "invalid name input" notification

Outcome 2
Input: "abc" into customer name field
Expected output: passed validation

3.12 Unit Test Two
Function Test: Delete existing customer
Name of Test (what to test for): valid user input

Outcome 1
Input: "5" into entry to delete field
Expected Output: "invalid customer selected" notification

Outcome 2
Input: any valid value (i.e. existing customer)
Expected Output: "entry deleted successfully" notification

4.0 Future Enhancements Beyond the aforementioned security concerns, improved search functionality to allow partial searches or for multiple filters is another good improvement.
Next would be to implement some form of centralized database to store the customer data to facilitate multiple stores or points of access since the customers cannot be expected to only visit the one store which has their data,for example.