feat(database): add closable connection wrapper for PDO connection

[blackshadev]

What

Closes #872

• add closable connection wrapper for PDO connection

Why

• As mentioned in feat(console): add task component #857 it is sometimes needed to manually close the PDO connection. With this PR you can manually close (and re-connect) the PDO connection.
• Additionally, in the future this code can be expanded upon to have multiple active connections, or even other "kinds" of connections besides PDO

[innocenzi]

That looks great! Can you think of a way to test that the connection is actually closed? 🤔

[innocenzi]

If this is only meant to be used in tests, can we ensure we are actually running in tests? We can check the current environment from the Kernel I believe

[blackshadev]

This was a cary over from the PDOInitializer which had the same. But yeah, good suggestion. I will make it such that it only "caches" when in testing. This is more of a test speed+memory improvement than anything else.

[blackshadev]

Implemented the check.

[blackshadev]

That looks great! Can you think of a way to test that the connection is actually closed? 🤔

It depends on your meaning of "test".. I can Add a test for the close functionality: yes. It will just check if the PDO connection has been set to null. I cannot test if the PDO driver really closes the connection, PDO doesn't expose anything for this.

Do you want me to add a unit test for the connect + close functionality?

[innocenzi]

I think what would be ideal is that the PdoConnection class throws a ConnectionClosed exception when the internal $pdo variable is accessed if it's null. Right now, I think if we close the connection and try a query, we will have a cannot call method on null type exception.

Then, we can write a test that first ensure the connection works by issuing a query, then closing the connection, and finally expecting the exception when issuing another query

[blackshadev]

I think what would be ideal is that the PdoConnection class throws a ConnectionClosed exception when the internal $pdo variable is accessed if it's null. Right now, I think if we close the connection and try a query, we will have a cannot call method on null type exception.

Then, we can write a test that first ensure the connection works by issuing a query, then closing the connection, and finally expecting the exception when issuing another query

Implemented the exception and the test using sqllite.