toasty 0.4.0

An async ORM for Rust supporting SQL and NoSQL databases
Documentation 
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use super::test_schema;
use crate::engine::simplify::Simplify;
use toasty_core::stmt::{self, Expr, ExprExists, Query, Values, VisitMut as _};

/// Creates a query with no rows (empty VALUES clause).
fn empty_query() -> Box<Query> {
    Box::new(Query::values(Values::default()))
}

/// Creates a query with one row containing a single value.
fn non_empty_query() -> Box<Query> {
    let mut values = Values::default();
    values.rows.push(stmt::Expr::Value(stmt::Value::from(1i64)));
    Box::new(Query::values(values))
}

#[test]
fn exists_empty_query_becomes_false() {
    let schema = test_schema();
    let simplify = Simplify::new(&schema);

    // `exists(empty_query)` → `false`
    let expr = ExprExists {
        subquery: empty_query(),
    };
    let result = simplify.simplify_expr_exists(&expr);

    assert!(result.is_some());
    assert!(result.unwrap().is_false());
}

#[test]
fn exists_non_empty_query_not_simplified() {
    let schema = test_schema();
    let simplify = Simplify::new(&schema);

    // `exists(non_empty_query)`, non-empty, not simplified
    let expr = ExprExists {
        subquery: non_empty_query(),
    };
    let result = simplify.simplify_expr_exists(&expr);

    assert!(result.is_none());
}

#[test]
fn not_exists_empty_query_becomes_true() {
    let schema = test_schema();
    let mut simplify = Simplify::new(&schema);

    // `not(exists(empty_query))` → `not(false)` → `true`
    let mut expr = Expr::not(Expr::Exists(ExprExists {
        subquery: empty_query(),
    }));
    simplify.visit_expr_mut(&mut expr);
    assert!(expr.is_true());
}

#[test]
fn not_exists_non_empty_query_not_simplified() {
    let schema = test_schema();
    let mut simplify = Simplify::new(&schema);

    // `not(exists(non_empty_query))`, non-empty, not simplified
    let mut expr = Expr::not(Expr::Exists(ExprExists {
        subquery: non_empty_query(),
    }));
    simplify.visit_expr_mut(&mut expr);

    // Should remain as `not(exists(...))`
    assert!(matches!(expr, Expr::Not(_)));
}