Testing reference
The testing utilities are located in the NResilience.Testing namespace within the NResilience.Testing package.
Sequence
The Sequence class is a factory for creating scripted call sequences that return pre-defined results or throw exceptions.
| Member | Description |
|---|---|
Sequence.For<T>(TimeProvider? time = null) | Creates a scripted sequence that returns values of type T. |
Sequence.ForVoid(TimeProvider? time = null) | Creates a scripted sequence for void execution overloads, returning a Sequence<Void>. |
To ensure that scripted delays are handled deterministically and do not introduce real-time sleeps, pass the same TimeProvider to the Sequence that you provided to the resilience policy.
Sequence<T>
Sequence<T> allows you to define a series of outcomes to be served to the policy during a test.
| Member | Description |
|---|---|
Returns(T result) / Returns(T result, int count) | Appends one or more steps that return the specified result. |
Throws(Exception) / Throws(Exception, int count) | Appends one or more steps that throw the specified exception. The same exception instance is used for all counts, allowing for reference equality assertions in tests. |
Delays(TimeSpan) | Configures the next step to take the specified amount of time to complete. Multiple calls to Delays accumulate. |
NextAsync(CancellationToken) | Serves the next step in the sequence. This is the method typically used as the resilience callback. |
NextVoidAsync(CancellationToken) | Similar to NextAsync, but returns a Task to support void execution overloads. |
CallCount | The total number of calls served, including any call that exceeded the script length. |
Remaining | The number of steps remaining in the script. |
Execution behavior
- Timing: A step with no delay completes synchronously. A step with a delay suspends execution and observes the provided
CancellationToken. - Bounds: If a call is made after the script has been exhausted, the sequence throws an
InvalidOperationExceptionspecifying the script length and the call number. - Thread Safety: Building the script is not thread-safe, but serving the script via
NextAsyncis thread-safe.
EventRecorder
EventRecorder is a utility for capturing and asserting on the events emitted by a resilience policy.
| Member | Description |
|---|---|
Record(CallEvent) | The event listener method. Assign this to the policy's OnEvent property: policy with { OnEvent = recorder.Record }. |
Events | A collection of all captured events in the order they occurred. |
Kinds | A collection of all captured CallEventKind values. This is the primary surface for assertions. |
this[int index] | The event at the specified 0-based index. |
Count | The total number of captured events. |
CountOf(kind) | The number of events of a specific kind. |
Contains(kind) | true if at least one event of the specified kind was captured. |
OfKind(kind) | A collection of all events of the specified kind. |
Single(kind) | The only event of a specific kind. Throws an exception if more than one (or none) are found. |
Clear() | Clears all captured events, allowing the recorder to be reused in the same test. |
ToString() | Returns a human-readable list of all events, with one event per line. |
EventRecorder is thread-safe.