test(types): enable string association (#10487)

types/test/include.ts

-import { Model, Sequelize } from 'sequelize';
+import { Model, Sequelize, HasMany } from 'sequelize';
 
-class MyModel extends Model {}
+class MyModel extends Model {
+	public static associations: {
+		relation: HasMany
+	};
+}
 
 class AssociatedModel extends Model {}
 
@@ -22,3 +26,13 @@ MyModel.findAll({
 MyModel.findAll({
 	include: [{ all: true }],
 });
+
+MyModel.findAll({
+	include: [{
+		limit: 1,
+		association: 'relation',
+		order: [['id', 'DESC']],
+		separate: true,
+		where: { state: Sequelize.col('project.state') },
+	}]
+});