Test Framework

The crate provides two testing utilities:

TestFramework: Unit testing aggregates in isolation (no stores, no serialization)
RepositoryTestExt: Integration testing with real repositories (seeding data, simulating concurrency)

Enabling the Test Framework

Add the test-util feature to your dev dependencies:

[dev-dependencies]
sourcery = { version = "0.1", features = ["test-util"] }

Basic Usage

use sourcery::test::TestFramework;

#[test]
fn deposit_increases_balance() {
    TestFramework::<Account>::given(&[FundsDeposited { amount: 100 }.into()])
        .when(&Deposit { amount: 50 })
        .then_expect_events(&[FundsDeposited { amount: 50 }.into()]);
}

Given Methods

Set up initial state with given(events):

// With existing events
TestFramework::<Account>::given(&[
    FundsDeposited { amount: 100 }.into(),
    FundsWithdrawn { amount: 30 }.into(),
])  // Balance is now 70

// Fresh aggregate (pass empty slice)
TestFramework::<Account>::given(&[])  // Balance is 0

When Methods

`when(command)`

Execute a command against the aggregate:

.when(&Withdraw { amount: 50 })

Then Methods

Assert outcomes with these methods:

// Expect specific events (requires PartialEq on events)
.then_expect_events(&[FundsWithdrawn { amount: 50 }.into()])

// Expect no events (valid no-op)
.then_expect_no_events()

// Expect any error
.then_expect_error()

// Expect specific error
.then_expect_error_eq(&AccountError::InsufficientFunds)

Additional methods: then_expect_error_message(substring) for substring matching, inspect_result() to get the raw Result for custom assertions.

Complete Test Suite Example

use sourcery::test::TestFramework;

#[test]
fn deposits_positive_amount() {
    TestFramework::<Account>::given(&[])
        .when(&Deposit { amount: 100 })
        .then_expect_events(&[FundsDeposited { amount: 100 }.into()]);
}

#[test]
fn rejects_overdraft() {
    TestFramework::<Account>::given(&[FundsDeposited { amount: 100 }.into()])
        .when(&Withdraw { amount: 150 })
        .then_expect_error_eq(&AccountError::InsufficientFunds);
}

#[test]
fn rejects_invalid_deposit() {
    TestFramework::<Account>::given(&[])
        .when(&Deposit { amount: -50 })
        .then_expect_error();
}

Testing Projections

Projections don’t use TestFramework. Test them directly by calling init() and apply_projection():

#[test]
fn projection_aggregates_deposits() {
    let mut proj = AccountSummary::init(&());

    proj.apply_projection(&"ACC-001".to_string(), &FundsDeposited { amount: 100 }, &());
    proj.apply_projection(&"ACC-002".to_string(), &FundsDeposited { amount: 50 }, &());
    proj.apply_projection(&"ACC-001".to_string(), &FundsDeposited { amount: 25 }, &());

    assert_eq!(proj.accounts.get("ACC-001"), Some(&125));
    assert_eq!(proj.accounts.get("ACC-002"), Some(&50));
}

Design Decisions — Why the crate works this way

Sourcery