Crate double

Double is a fully-featured mocking library for mocking trait implementations.

The Mock struct tracks function call arguments and specifies return values or function overrides.

Examples

#[macro_use]
extern crate double;

// Code under test
trait BalanceSheet {
    fn profit(&self, revenue: u32, costs: u32) -> i32;
}

fn double_profit(revenue: u32, costs: u32, balance_sheet: &BalanceSheet) -> i32 {
    balance_sheet.profit(revenue, costs) * 2
}

// Test which uses a mock BalanceSheet
mock_trait!(
    MockBalanceSheet,
    profit(u32, u32) -> i32);
impl BalanceSheet for MockBalanceSheet {
    mock_method!(profit(&self, revenue: u32, costs: u32) -> i32);
}

fn test_doubling_a_sheets_profit() {
    // GIVEN:
    let sheet = MockBalanceSheet::default();
    sheet.profit.return_value(250);
    // WHEN:
    let profit = double_profit(500, 250, &sheet);
    // THEN:
    // mock return 250, which was double
    assert_eq!(500, profit);
    // assert that the revenue and costs were correctly passed to the mock
    sheet.profit.has_calls_exactly_in_order(vec!((500, 250)));
}

// Executing test
fn main() {
    test_doubling_a_sheets_profit();
}

Re-exports

pub use crate::mock::Mock;

Modules

macros
matcher
mock

Macros

__private_mock_trait_default_impl
__private_mock_trait_new_impl
matcher
mock_func
mock_func_no_default
mock_method	Macro that generates a mock implementation of a trait method.
mock_trait	Macro that generates a struct implementation of a trait.
mock_trait_no_default	Macro that generates a struct implementation of a trait.
p