Function create_tables 

pub async fn create_tables() -> Result<(), MigrateError>

Create a table for every registered model, deriving the schema from the models themselves.

A thin alias for umbral::migrate::create_tables_for_tests, which is where the implementation lives — the migration engine already knows how to turn a ModelMeta into DDL, and umbral-core’s own test suite needs the same helper without a dev-dependency cycle back through this crate.

This is the one that stops your tests lying to you. The alternative is a hand-written CREATE TABLE in the test file: a second source of truth for the schema, which drifts the moment a model grows a column. The ORM then queries a column that isn’t there, and any error-swallowing on the path (an unwrap_or(false)) turns that into a test that PASSES WITH THE WRONG ANSWER.

umbral::App::builder()
    .settings(settings)
    .database("default", pool.clone_handle())
    .model::<Note>()
    .build()?;

umbral_testing::create_tables().await?;   // schema == your models. always.

Idempotent, and works on both backends. Most tests want boot, which calls this for you.