This is a sample code for dependency injection and mocking.

1. Doing depedency injection
2. Mocking the DB call for unit testing
3. Generated mock files using mockery. I also have test that do not use it.
4. Minimal loging.

Installation

Install docker Then pull down mssql server lastest and get it up and running

sudo docker pull microsoft/mssql-server-linux:2017-latest
docker run -e 'HOMEBREW_NO_ENV_FILTERING=1' -e 'ACCEPT_EULA=Y' -e 'SA_PASSWORD=yourStrong(!)Password' -p 1433:1433 -d microsoft/mssql-server-linux

Install azure data studio GUI

brew cask install azure-data-studio

If you want to install sql command line unility knock your self out

brew tap microsoft/mssql-release https://github.com/Microsoft/homebrew-mssql-release
brew install --no-sandbox msodbcsql17 mssql-tools

DB script to get it up and running

CREATE DATABASE SampleDB;
GO

CREATE SCHEMA TestSchema;
GO

CREATE TABLE TestSchema.Employees (
  Id INT IDENTITY(1,1) NOT NULL PRIMARY KEY,
  Name NVARCHAR(50),
  Location NVARCHAR(50)
);
GO

INSERT INTO TestSchema.Employees (Name, Location) VALUES
(N'Jared', N'Australia'),
(N'Nikita', N'India'),
(N'Tom', N'Germany');
GO

SELECT * FROM TestSchema.Employees;
GO

Dependency injection

1. Dependency injection is a technique whereby one object supplies the dependencies of another object.
2. Things that are commonly injected to handle. Database connection, loggers, configurations....
3. Can be achieved through constructor, setter methods and interfaces

Advantages

1. Helps in unit testing. Along with mocking.
2. Extending the application becomes easy.
3. Helps create loosely coupled objects.

Disadvantages

1. Can be little complex to set up and learn initially.
2. Usually implemented with reflection or dynamic programming. Does not work well with IDE automation