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perf: lazily initialize optional MockEngine collections #5289

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Merged
thomhurst merged 6 commits into from
Mar 29, 2026
Merged

perf: lazily initialize optional MockEngine collections #5289

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b41aae2
perf: lazily initialize optional MockEngine collections
thomhurst Mar 28, 2026
0d1af88
fix: thread-safe lazy init and simpler Reset in MockEngine
thomhurst Mar 28, 2026
2ff156d
chore: modernize Substring(4) to range syntax [4..]
thomhurst Mar 28, 2026
5a827c2
fix: use LazyInitializer + Volatile.Read for safe lazy init
thomhurst Mar 28, 2026
0ae6d8c
fix: use Volatile.Write in Reset() to pair with Volatile.Read
thomhurst Mar 28, 2026
664568f
fix: CS8603 on netstandard2.0 for LazyInitializer.EnsureInitialized
thomhurst Mar 29, 2026
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68 changes: 46 additions & 22 deletions TUnit.Mocks/MockEngine.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@
using TUnit.Mocks.Setup.Behaviors;
using TUnit.Mocks.Verification;
using System.Collections.Concurrent;
using System.Threading;
using System.ComponentModel;

namespace TUnit.Mocks;
Expand All @@ -24,11 +25,12 @@ public sealed class MockEngine<T> : IMockEngineAccess where T : class
private readonly Dictionary<int, List<MethodSetup>> _setupsByMember = new();
private readonly Lock _setupLock = new();
private readonly ConcurrentQueue<CallRecord> _callHistory = new();
private readonly ConcurrentDictionary<string, object?> _autoTrackValues = new();
private readonly ConcurrentQueue<(string EventName, bool IsSubscribe)> _eventSubscriptions = new();
private readonly ConcurrentDictionary<string, Action> _onSubscribeCallbacks = new();
private readonly ConcurrentDictionary<string, Action> _onUnsubscribeCallbacks = new();
private readonly ConcurrentDictionary<string, IMock?> _autoMockCache = new();

private ConcurrentDictionary<string, object?>? _autoTrackValues;
private ConcurrentQueue<(string EventName, bool IsSubscribe)>? _eventSubscriptions;
private ConcurrentDictionary<string, Action>? _onSubscribeCallbacks;
private ConcurrentDictionary<string, Action>? _onUnsubscribeCallbacks;
private ConcurrentDictionary<string, IMock?>? _autoMockCache;

/// <summary>
/// The current state name for state machine mocking. Null means no state (all setups match).
Expand Down Expand Up @@ -77,6 +79,21 @@ public MockEngine(MockBehavior behavior)
Behavior = behavior;
}

private ConcurrentDictionary<string, object?> AutoTrackValues
=> LazyInitializer.EnsureInitialized(ref _autoTrackValues)!;

private ConcurrentQueue<(string EventName, bool IsSubscribe)> EventSubscriptions
=> LazyInitializer.EnsureInitialized(ref _eventSubscriptions)!;

private ConcurrentDictionary<string, Action> OnSubscribeCallbacks
=> LazyInitializer.EnsureInitialized(ref _onSubscribeCallbacks)!;

private ConcurrentDictionary<string, Action> OnUnsubscribeCallbacks
=> LazyInitializer.EnsureInitialized(ref _onUnsubscribeCallbacks)!;

private ConcurrentDictionary<string, IMock?> AutoMockCache
=> LazyInitializer.EnsureInitialized(ref _autoMockCache)!;

/// <summary>
/// Transitions the engine to the specified state. Null clears the state.
/// </summary>
Expand Down Expand Up @@ -125,7 +142,7 @@ public void HandleCall(int memberId, string memberName, object?[] args)
// Auto-track property setters: store value keyed by property name
if (AutoTrackProperties && memberName.StartsWith("set_", StringComparison.Ordinal) && args.Length > 0)
{
_autoTrackValues[memberName.Substring(4)] = args[0];
AutoTrackValues[memberName[4..]] = args[0];
}

var (setupFound, behavior, matchedSetup) = FindMatchingSetup(memberId, args);
Expand Down Expand Up @@ -211,9 +228,9 @@ public TReturn HandleCallWithReturn<TReturn>(int memberId, string memberName, ob
callRecord.IsUnmatched = true;

// Auto-track property getters: return stored value if available
if (AutoTrackProperties && memberName.StartsWith("get_", StringComparison.Ordinal))
if (AutoTrackProperties && Volatile.Read(ref _autoTrackValues) is { } trackValues && memberName.StartsWith("get_", StringComparison.Ordinal))
{
if (_autoTrackValues.TryGetValue(memberName.Substring(4), out var trackedValue))
if (trackValues.TryGetValue(memberName[4..], out var trackedValue))
{
if (trackedValue is TReturn typed) return typed;
if (trackedValue is null) return default(TReturn)!;
Expand All @@ -236,7 +253,7 @@ public TReturn HandleCallWithReturn<TReturn>(int memberId, string memberName, ob
if (Behavior == MockBehavior.Loose && typeof(TReturn).IsInterface)
{
var cacheKey = memberName + "|" + typeof(TReturn).FullName;
var autoMock = _autoMockCache.GetOrAdd(cacheKey, _ =>
var autoMock = AutoMockCache.GetOrAdd(cacheKey, _ =>
{
Mock.TryCreateAutoMock(typeof(TReturn), Behavior, out var m);
return m;
Expand Down Expand Up @@ -465,7 +482,12 @@ public Diagnostics.MockDiagnostics GetDiagnostics()
[EditorBrowsable(EditorBrowsableState.Never)]
public bool TryGetAutoMock(string cacheKey, [System.Diagnostics.CodeAnalysis.NotNullWhen(true)] out IMock? mock)
{
return _autoMockCache.TryGetValue(cacheKey, out mock);
if (Volatile.Read(ref _autoMockCache) is not { } cache)
{
mock = null;
return false;
}
return cache.TryGetValue(cacheKey, out mock);
}

/// <summary>
Expand All @@ -483,11 +505,11 @@ public void Reset()
// Drain the queue
while (_callHistory.TryDequeue(out _)) { }

_autoTrackValues.Clear();
while (_eventSubscriptions.TryDequeue(out _)) { }
_onSubscribeCallbacks.Clear();
_onUnsubscribeCallbacks.Clear();
_autoMockCache.Clear();
Volatile.Write(ref _autoTrackValues, null);
Volatile.Write(ref _eventSubscriptions, null);
Volatile.Write(ref _onSubscribeCallbacks, null);
Volatile.Write(ref _onUnsubscribeCallbacks, null);
Volatile.Write(ref _autoMockCache, null);
}

/// <summary>
Expand All @@ -496,7 +518,7 @@ public void Reset()
[EditorBrowsable(EditorBrowsableState.Never)]
public void OnSubscribe(string eventName, Action callback)
{
_onSubscribeCallbacks[eventName] = callback;
OnSubscribeCallbacks[eventName] = callback;
}

/// <summary>
Expand All @@ -505,7 +527,7 @@ public void OnSubscribe(string eventName, Action callback)
[EditorBrowsable(EditorBrowsableState.Never)]
public void OnUnsubscribe(string eventName, Action callback)
{
_onUnsubscribeCallbacks[eventName] = callback;
OnUnsubscribeCallbacks[eventName] = callback;
}

/// <summary>
Expand All @@ -514,18 +536,18 @@ public void OnUnsubscribe(string eventName, Action callback)
[EditorBrowsable(EditorBrowsableState.Never)]
public void RecordEventSubscription(string eventName, bool isSubscribe)
{
_eventSubscriptions.Enqueue((eventName, isSubscribe));
EventSubscriptions.Enqueue((eventName, isSubscribe));

if (isSubscribe)
{
if (_onSubscribeCallbacks.TryGetValue(eventName, out var callback))
if (Volatile.Read(ref _onSubscribeCallbacks) is { } subCallbacks && subCallbacks.TryGetValue(eventName, out var callback))
{
callback();
}
}
else
{
if (_onUnsubscribeCallbacks.TryGetValue(eventName, out var callback))
if (Volatile.Read(ref _onUnsubscribeCallbacks) is { } unsubCallbacks && unsubCallbacks.TryGetValue(eventName, out var callback))
{
callback();
}
Expand All @@ -538,8 +560,9 @@ public void RecordEventSubscription(string eventName, bool isSubscribe)
[EditorBrowsable(EditorBrowsableState.Never)]
public int GetEventSubscriberCount(string eventName)
{
if (Volatile.Read(ref _eventSubscriptions) is not { } subs) return 0;
int count = 0;
foreach (var (name, isSub) in _eventSubscriptions)
foreach (var (name, isSub) in subs)
{
if (name == eventName)
{
Expand All @@ -555,7 +578,8 @@ public int GetEventSubscriberCount(string eventName)
[EditorBrowsable(EditorBrowsableState.Never)]
public bool WasEventSubscribed(string eventName)
{
foreach (var (name, isSub) in _eventSubscriptions)
if (Volatile.Read(ref _eventSubscriptions) is not { } subs) return false;
foreach (var (name, isSub) in subs)
{
if (name == eventName && isSub) return true;
}
Expand Down
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