refactor: move database client to tests/common

[sunng87]

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Refer to a related PR or issue link (optional)

Resolves dependencies issue introduced in #3820

What's changed and what's your intention?

This patch extract database.rs to standalone module to avoid introducing whole dependency tree of tests-integration.

Also it removes dependency from benchmarks which is obsolete.

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.
• This PR requires documentation updates.

[sunng87]

another question about this: because we already have testing feature in client, is it really necessary to move database.rs out of client?

[sunng87]

and we do have only one testing function in client for which we can't remove testing from client at the moment.

[tisonkun]

I agree we can move this struct to client crate behind the testing feature.

IIRC previously it's in the client crate without testing feature in control.

[sunng87]

I think we can close this one, revert #3820, and create a new patch to feature-gate database.rs

[tisonkun]

Yeah. This is possible. Would you follow these changes?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.10%. Comparing base (097f62f) to head (fb51741).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4057      +/-   ##
==========================================
- Coverage   85.41%   85.10%   -0.31%     
==========================================
  Files         985      985              
  Lines      170616   170616              
==========================================
- Hits       145724   145205     -519     
- Misses      24892    25411     +519     

[tisonkun]

I'm manually reverting this. The related files changed a bit .