Class LogSnapshotRenderer

Namespace

LogAssertions.Render

Assembly

LogAssertions.dll

Pure renderer that converts a Microsoft.Extensions.Logging.Testing.FakeLogCollector's captured records into deterministic, snapshot-friendly multi-line text. Each record renders as a header line ([NN] level category "message") followed by optional indented detail lines for structured state, active scopes, and an attached exception. Records are separated by a single blank line.

public static class LogSnapshotRenderer

Inheritance

object

LogSnapshotRenderer

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Remarks

Stability contract. Unlike LogAssertionRendering (whose output is explicitly documented as not stable and is meant only for failure messages), the output of this renderer is a stable, pin-able contract. Snapshot baselines produced by Render(FakeLogCollector, LogSnapshotOptions?) are intended to be committed and diffed. A change to the rendered shape is a versioned, documented change.

Pairs with snapshot assertions. Render once, then pin the result against a baseline:

var rendered = LogSnapshotRenderer.Render(collector);
await Assert.That(rendered).MatchesSnapshot();

The MatchesSnapshot() extension lives in the sibling SnapshotAssertions.TUnit package; this package does not depend on it. The two-line composition is deliberate: it lets consumers reach for the renderer without committing to a specific snapshot framework, and keeps the snapshot package an opt-in pairing rather than a transitive dependency.

No baked-in scrubbing. This renderer emits the captured text verbatim; it does not scrub GUIDs, timestamps, or durations out of message bodies. Volatile values are the concern of the snapshot layer: compose SnapshotAssertions.Scrubbers at the MatchesSnapshot() call site. Keeping rendering and scrubbing separate means the renderer has one job, the scrubber set stays in one place, and neither has to know about the other.

Deterministic line endings. Lines are terminated with the literal LF byte ('\n'), never NewLine. The CRLF / LF split between Windows and Unix would otherwise serialise the same records differently per OS, breaking snapshot baselines on cross-platform CI. Hardcoding LF keeps a baseline committed on one platform valid for test runs on every other.

Capture-order preserving. Records render in the order Microsoft.Extensions.Logging.Testing.FakeLogCollector captured them; the renderer never sorts. A regression that keeps per-record predicate assertions passing while reordering, dropping, or inserting records still surfaces as a snapshot diff.

Defensive structured-state handling. The renderer reads Microsoft.Extensions.Logging.Testing.FakeLogRecord state through the Microsoft.Extensions.Logging.Testing.FakeLogRecord.StructuredState property inside a try/catch for InvalidCastException. That property hard-casts the captured state to a key-value-pair list and throws when it is not one (e.g. ILogger.Log<TState> with a custom typed state); a record with non-KVP state simply renders without a state: line instead of throwing.

Methods

Render(FakeLogCollector, LogSnapshotOptions?)

Renders every captured record from collector into a deterministic, snapshot-friendly multi-line string.

public static string Render(FakeLogCollector collector, LogSnapshotOptions? options = null)

Parameters

collector FakeLogCollector

The fake collector whose captured records to render.

options LogSnapshotOptions

Rendering options, or null for Default.

Returns

string

A multi-line string with one block per captured record, or Empty when the collector has captured nothing.

Exceptions

ArgumentNullException

collector is null.