feat(dp): migration tests framework + poc test

[WojSad]

Signed-off-by: Wojciech Sadowy wojciech.sadowy@freedomfi.com

feat(dp): migration tests framework + poc test

Summary

Added AlembicTestCase allowing to test python migrations, check database state before and after the migration, test individual tables etc.

[github-actions]

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[jkmar]

It is possible to create different kind of test:

• specify some data before migration (that would be some records in the database)
• specify expected data after migration

For example suppose that we have the following table:

CREATE TABLE T (ID INT);

And the following records:

INSERT INTO T VALUES(1);
INSERT INTO T VALUES(2);

now when we execute the following migration:

ALTER TABLE T ADD COLUMN A INT;
UPDATE T SET A = ID;

then we should get the following result:

SELECT * FROM T
ID, A
1, 1
2, 2

So the question is can we do it with this version of a framework?