@GetMapping
    @Operation(security = @SecurityRequirement(name = "keycloak"))
    public Iterable<Product> findProducts(@RequestParam(name = "filter", required = false) String filter) {
        return this.productService.findAllProducts(filter);
    }
@Test
    void findProduct_ReturnsProductsList() {
        // given
        var filter = "товар";

        doReturn(List.of(new Product(1, "Первый товар", "Описание первого товара"),
                new Product(2, "Второй товар", "Описание второго товара")))
                .when(this.productService).findAllProducts("товар");

        // when
        var result = this.controller.findProducts(filter);

        // then
        assertEquals(List.of(new Product(1, "Первый товар", "Описание первого товара"),
                new Product(2, "Второй товар", "Описание второго товара")), result);
    }