// Package dbtest gives each test a database of its own and runs raw
// SQL on it. Only tests may import it.
package dbtest

import (
	"crypto/rand"
	"database/sql"
	"testing"

	_ "modernc.org/sqlite" // registers the sqlite driver
)

// NewURL returns the URL of a new, empty in-memory database for one
// test. SQLite deletes an in-memory database when its last connection
// closes. A pool closes a connection when a query on it is cancelled
// while it runs. So this function holds a connection of its own open
// until the test ends.
func NewURL(tb testing.TB) string {
	tb.Helper()

	// A random name, so that no other test can share the database.
	dbURL := "file:" + rand.Text() + "?mode=memory&cache=shared"

	pool, err := sql.Open("sqlite", dbURL)
	if err != nil {
		tb.Fatalf("open test database: %v", err)
	}

	tb.Cleanup(func() { _ = pool.Close() })

	conn, err := pool.Conn(tb.Context())
	if err != nil {
		tb.Fatalf("connect to test database: %v", err)
	}

	tb.Cleanup(func() { _ = conn.Close() })

	return dbURL
}

// Exec runs one raw SQL statement on the database at dbURL, over a
// connection of its own. A test uses it for what the methods of
// db.Database cannot do, such as creating a trigger that makes a
// write fail.
func Exec(tb testing.TB, dbURL, statement string) {
	tb.Helper()

	pool, err := sql.Open("sqlite", dbURL)
	if err != nil {
		tb.Fatalf("open test database: %v", err)
	}

	defer func() { _ = pool.Close() }()

	_, err = pool.ExecContext(tb.Context(), statement)
	if err != nil {
		tb.Fatalf("run %q: %v", statement, err)
	}
}