What this does

Starts work on coder/internal#869

DBAuthz tests are taking a long amount of time from the sheer quantity of databases required to be provisioned. This PR adds a framework to move to a mocked db. And therefore massively speed up these tests.

The biggest challenge was to randomly seed data into the various database.<type> structs, as zero values could hide rbac bugs. In the actual db, we use dbgen. Instead of refactoring out or redoing dbgen to allow it to work with mocks, I went with https://github.com/brianvoe/gofakeit to randomly seed data.

Since we are not testing the db or queries themselves, I feel more ok with actual "random" data. The dbgen is hand rolled, but those fake values must confine to our data schema.

Maybe in the future we can annotate our models with faker tags and merge these ideas. At present, I don't think we can add field tags to sqlc output.

Should we be using a real database?

No, not really. The dbauthz tests are just asserting that all database calls have a corresponding authz check. There is no need to test the db layer here. The only reason we used a database, is because we used to have dbmem, and the tooling for setting up fake data was there and easy to use.

An example migrating to a mocked test

- s.Run("GetAPIKeysByUserID", s.Subtest(func(db database.Store, check *expects) {
+ s.Run("GetAPIKeysByUserID", s.Mocked(func(dbm *dbmock.MockStore, faker *gofakeit.Faker, check *expects) {
-	u1 := dbgen.User(s.T(), db, database.User{})
-	u2 := dbgen.User(s.T(), db, database.User{})
+       u1 := testutil.Fake(s.T(), faker, database.User{}) 

-	keyA, _ := dbgen.APIKey(s.T(), db, database.APIKey{UserID: u1.ID, LoginType: database.LoginTypeToken, TokenName: "key-a"})
-	keyB, _ := dbgen.APIKey(s.T(), db, database.APIKey{UserID: u1.ID, LoginType: database.LoginTypeToken, TokenName: "key-b"})
-	_, _ = dbgen.APIKey(s.T(), db, database.APIKey{UserID: u2.ID, LoginType: database.LoginTypeToken})
+       dbm.EXPECT().GetAPIKeysByUserID(gomock.Any(), gomock.Any()).Return(slice.New(keyA, keyB), nil).AnyTimes()

	check.Args(database.GetAPIKeysByUserIDParams{LoginType: database.LoginTypeToken, UserID: u1.ID}).
		Asserts(keyA, policy.ActionRead, keyB, policy.ActionRead).
		Returns(slice.New(keyA, keyB))
}))

Annotated output

// Moved from `s.Subtest` to `s.Mocked`. The mocker comes with a `faker` tool
s.Run("GetAPIKeysByUserID", s.Mocked(func(dbm *dbmock.MockStore, faker *gofakeit.Faker, check *expects) {
	// Instead of dbgen, we use `testutil.Fake(` to make populate random data
	u1 := testutil.Fake(s.T(), faker, database.User{})
	// The test util keeps non-zero values, so we keep our relations of objects
	keyA := testutil.Fake(s.T(), faker, database.APIKey{UserID: u1.ID, LoginType: database.LoginTypeToken, TokenName: "key-a"})
	keyB := testutil.Fake(s.T(), faker, database.APIKey{UserID: u1.ID, LoginType: database.LoginTypeToken, TokenName: "key-b"})

	// We need to add the mocked return and add 'AnyTimes'. The dbauthz package
	// runs multiple tests on this query method, so always use 'AnyTimes'.
	dbm.EXPECT().GetAPIKeysByUserID(gomock.Any(), gomock.Any()).Return(slice.New(keyA, keyB), nil).AnyTimes()
	check.Args(database.GetAPIKeysByUserIDParams{LoginType: database.LoginTypeToken, UserID: u1.ID}).
	Returns(slice.New(keyA, keyB))
}))