Database tests fail if no env variables are set and when they are run twice.

[mmartinv]

Running cargo test fails in database tests if no env variables are set:

 cargo test -p fdo-db --lib
    Finished test [unoptimized + debuginfo] target(s) in 0.09s
     Running unittests src/lib.rs (target/debug/deps/fdo_db-307ba6269451e378)

running 3 tests
test sqlite::tests::test_manufacturer_database ... FAILED
test sqlite::tests::test_owner_database ... FAILED
test sqlite::tests::test_rendezvous_database ... FAILED

failures:

---- sqlite::tests::test_manufacturer_database stdout ----
Current directory: Ok("/home/mmartinv/devel/src/github.com/fdo-rs/fido-device-onboard-rs/db")
thread 'sqlite::tests::test_manufacturer_database' panicked at db/src/sqlite.rs:35:14:
SQLITE_MANUFACTURER_DATABASE_URL must be set: NotPresent
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

---- sqlite::tests::test_owner_database stdout ----
Current directory: Ok("/home/mmartinv/devel/src/github.com/fdo-rs/fido-device-onboard-rs/db")
thread 'sqlite::tests::test_owner_database' panicked at db/src/sqlite.rs:103:51:
SQLITE_OWNER_DATABASE_URL must be set: NotPresent

---- sqlite::tests::test_rendezvous_database stdout ----
Current directory: Ok("/home/mmartinv/devel/src/github.com/fdo-rs/fido-device-onboard-rs/db")
thread 'sqlite::tests::test_rendezvous_database' panicked at db/src/sqlite.rs:221:14:
SQLITE_RENDEZVOUS_DATABASE_URL must be set: NotPresent


failures:
    sqlite::tests::test_manufacturer_database
    sqlite::tests::test_owner_database
    sqlite::tests::test_rendezvous_database

test result: FAILED. 0 passed; 3 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

error: test failed, to rerun pass `-p fdo-db --lib`

It would be great if the databases were created and configured automatically before running the tests.
Also some of the database tests fail when running the tests twice:

export SQLITE_MANUFACTURER_DATABASE_URL=sqlite://manufacturer.db ; 
diesel migration run --migration-dir migrations/migrations_manufacturing_server_sqlite --database-url $SQLITE_MANUFACTURER_DATABASE_URL
Running migration 2023-10-03-152801_create_db

export SQLITE_OWNER_DATABASE_URL=sqlite://owner.db
diesel migration run --migration-dir migrations/migrations_owner_onboarding_server_sqlite --database-url $SQLITE_OWNER_DATABASE_URL
Running migration 2023-10-03-152801_create_db

export SQLITE_RENDEZVOUS_DATABASE_URL=sqlite://rendezvous.db ; 
diesel migration run --migration-dir migrations/migrations_rendezvous_server_sqlite --database-url $SQLITE_RENDEZVOUS_DATABASE_URL 
Running migration 2023-10-03-152801_create_db

mv *.db db/

# First execution goes well
cargo test -p fdo-db --lib
    Finished test [unoptimized + debuginfo] target(s) in 0.11s
     Running unittests src/lib.rs (target/debug/deps/fdo_db-307ba6269451e378)

running 3 tests
test sqlite::tests::test_rendezvous_database ... ok
test sqlite::tests::test_manufacturer_database ... ok
test sqlite::tests::test_owner_database ... ok

test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.14s

# Second execution fails
cargo test -p fdo-db --lib
    Finished test [unoptimized + debuginfo] target(s) in 0.09s
     Running unittests src/lib.rs (target/debug/deps/fdo_db-307ba6269451e378)

running 3 tests
test sqlite::tests::test_owner_database ... FAILED
test sqlite::tests::test_manufacturer_database ... ok
test sqlite::tests::test_rendezvous_database ... ok

failures:

---- sqlite::tests::test_owner_database stdout ----
Current directory: Ok("/home/mmartinv/devel/src/github.com/fdo-rs/fido-device-onboard-rs/db")
Error: UNIQUE constraint failed: owner_vouchers.guid


failures:
    sqlite::tests::test_owner_database

test result: FAILED. 2 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.10s

[7flying]

The second failure is expected (and just in the owner database) since the test does not remove all the OVs. The tests expect an empty database at every run.