How to write Unit Tests with Service Locator

Step-by-step example how to write Salesforce Apex unit tests using the Service Locator pattern.
Salesforce Unit Test Best Practices

TrueSolv guide to Salesforce Apex unit test to validate logic and keep deployments reliable without SeeAllData.
How to increase code coverage quickly in Salesforce

TrueSolv explains Salesforce Apex code coverage for deployments and AppExchange packages for safer releases.