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Combining Assertions

TUnit provides several ways to combine multiple assertions within a single test: chaining with .And and .Or, and grouping with Assert.Multiple().

And Conditions​

Use the .And property to chain multiple conditions on the same value. Every condition must pass for the assertion to succeed. This reads naturally and avoids repeating Assert.That(...) for each check.

[Test]
public async Task MyTest()
{
    var result = Add(1, 2);

    await Assert.That(result)
        .IsNotNull()
        .And.IsPositive()
        .And.IsEqualTo(3);
}

Or Conditions​

Use the .Or property when at least one condition must pass. This is useful for values that are valid across a known set of outcomes.

[Test]
public async Task MyTest()
{
    var result = ComputeValue();

    await Assert.That(result)
        .IsEqualTo(2)
        .Or.IsEqualTo(3)
        .Or.IsEqualTo(4);
}

.And and .Or can be mixed in a single chain. Conditions are evaluated left-to-right.

Assertion Scopes​

By default, a failing assertion throws immediately and stops the test. Assert.Multiple() creates a scope that collects all failures and reports them together when the scope exits. This is useful for asserting multiple properties on an object without the fix-one-rerun-fix-another cycle.

Implicit scope (covers the rest of the method):

[Test]
public async Task MyTest()
{
    var result = Add(1, 2);

    using var _ = Assert.Multiple();

    await Assert.That(result).IsPositive();
    await Assert.That(result).IsEqualTo(3);
}

Explicit scope (covers only the block):

[Test]
public async Task MyTest()
{
    var result = Add(1, 2);

    using (Assert.Multiple())
    {
        await Assert.That(result).IsPositive();
        await Assert.That(result).IsEqualTo(3);
    }
}

Both forms aggregate failures. When the using scope ends, any accumulated assertion failures are thrown as a single exception listing all violations.

See Also​