Implement MultiDB Support and Tests

[tom-andersen]

No description provided.

[google-oss-bot]

Size Report ¹

Affected Products

• FirebaseFirestore

  Type	Base (0dd5b06)	Merge (81816c3)	Diff
  CocoaPods	?	-51.5 kB	? (?)

Test Logs

• Merge (81816c3): https://github.com/firebase/firebase-ios-sdk/actions/runs/3421416663

1. https://storage.googleapis.com/firebase-sdk-metric-reports/4qPQAdeaIE.html

[mortenbekditlevsen]

Wow! This is a dream come true! 🥰

[google-oss-bot]

Coverage Report ¹

Affected Products

• FirebaseFirestore-iOS-FirebaseFirestore.framework

  Overall coverage changed from 88.26% (7196035) to 88.28% (59cf567) by +0.03%.

  Filename	Base (7196035)	Merge (59cf567)	Diff
  FIRFirestore.mm	87.87%	89.56%	+1.69%
  ordered_code.cc	94.39%	93.90%	-0.49%
  write_stream.cc	91.55%	94.37%	+2.82%

Test Logs

• Base (7196035): https://github.com/firebase/firebase-ios-sdk/actions/runs/3527941281
• Merge (59cf567): https://github.com/firebase/firebase-ios-sdk/actions/runs/3534118368

1. https://storage.googleapis.com/firebase-sdk-metric-reports/TmZZlKqpjF.html

[wu-hui]

Normally we also run a sanity Swift test to see if the API is as expected in Swift. You might not be able to do this because the API from obj-c is not exposed..

Please add a TODO for yourself to add swift test, before we actually release it in the future.