Tests for last-seen state calculation and comparison

[nolar]

Issue : #13

Add tests for last-seen state (calculation and comparison).

The last seen state is used to detect the causes when something was changed (and what specifically), or to detect of the object is completely new (no previous seen state).

Partially, this is tested in the causation tests (indirectly). But there, it tests for how the states & diffs are used, without testing the details on the field level, and not all functions are fully tested.

The diff calculation (between old & new states) is left aside, as there are separate tests for it in /tests/diffs/.

[zincr]

🤖 zincr found 0 problems , 1 warning

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Large Commits

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This file contains a substantial change, please review to determine if the change comes from an external source and if there are any copyright or licensing issues to be aware of

• ℹ️ kopf/test_lastseen.py had +100 lines of code changed in a single commit
  Please review this file to determine the source of this change
   

[zincr]

🤖 zincr found 1 problem , 1 warning

❌ Approvals
ℹ️ Large Commits
✅ Specification
✅ Dependency Licensing

Details on how to resolve are provided below

---

Approvals

All proposed changes must be reviewed by project maintainers before they can be merged

Not enough people have approved this pull request - please ensure that 1 additional user, who have not contributed to this pull request approve the changes.

• ✅ Approved by PR author @nolar
• ❌ 1 additional approval needed
   

Large Commits

Checks all commits for large additions to a single file. Large commits should be reviewed more carefully for potential copyright and licensing issues

This file contains a substantial change, please review to determine if the change comes from an external source and if there are any copyright or licensing issues to be aware of

• ℹ️ kopf/test_lastseen.py had +100 lines of code changed in a single commit
  Please review this file to determine the source of this change