Class Mocker

Core mock coordinator (provider-based creation integrated).

Inheritance
object
Mocker
Implements
Inherited Members
Namespace: FastMoq
Assembly: FastMoq.Core.dll
Syntax
public class Mocker : IDisposable, IAsyncDisposable
Remarks

Resolution Hierarchy (v4)

FastMoq uses consistent resolution hierarchies across different APIs:

GetObject<T>() - Dependency Injection (Property/Field/Constructor)

  1. Custom registration via AddType<T>() or AddKnownType<T>()
  2. Built-in known instances (e.g., IFileSystem returns in-memory file system)
  3. Tracked mocks via GetOrCreateFastMock (get-or-create paradigm)
  4. Default value (null or type default)

GetObject respects all custom configurations and auto-creates mocks when needed.

GetMock<T>() / GetOrCreateMock<T>() - Test Setup (Mock-Only Path)

  1. Tracked mocks only (get-or-create tracked mock, no custom registrations applied)
  2. Mocks are preconfigured via SetupFastMock (e.g., IFileSystem delegates to built-in)

GetMock/GetOrCreateMock always return tracked mocks for test setup, bypassing custom AddType registrations. This is intentional: AddType is for runtime instances, while GetMock is for test mocks. For setup values, use AddMock() or component constructor parameters instead.

GetParameter() - Constructor Parameter Resolution

  1. Custom type mapping (AddType<TInterface, TImpl>())
  2. Falls back to GetObject for all other resolution

Constructor parameters follow the same hierarchy as GetObject after type mapping.

Examples

Use Mocker as the main test composition root when you want provider-first arrangement based on concrete registrations and policy-driven construction.

var fileSystem = new MockFileSystem();
fileSystem.AddFile(@"c:\orders\42.json", new MockFileData("{ \"id\": 42, \"total\": 125.50 }"));

var mocker = new Mocker()
.AddType<IFileSystem>(fileSystem);


var resolvedFileSystem = mocker.GetRequiredObject<IFileSystem>();


resolvedFileSystem.File.Exists(@"c:\orders\42.json").Should().BeTrue();
resolvedFileSystem.Should().BeSameAs(fileSystem);

Constructors

Mocker()

Initializes a new Mocker instance with a no-op external logging callback.

Declaration
public Mocker()

Mocker(Action<LogLevel, EventId, string, Exception?>)

Initializes a new Mocker instance with an exception-aware logging callback.

Declaration
public Mocker(Action<LogLevel, EventId, string, Exception?> loggingCallback)
Parameters
Type Name Description
Action<LogLevel, EventId, string, Exception> loggingCallback

Callback invoked for log entries emitted by this mocker.

Mocker(Action<LogLevel, EventId, string>)

Initializes a new Mocker instance with a three-parameter logging callback.

Declaration
public Mocker(Action<LogLevel, EventId, string> loggingCallback)
Parameters
Type Name Description
Action<LogLevel, EventId, string> loggingCallback

Callback invoked for log entries emitted by this mocker.

Mocker(Dictionary<Type, IInstanceModel>)

Initializes a new Mocker instance with an existing type map.

Declaration
public Mocker(Dictionary<Type, IInstanceModel> map)
Parameters
Type Name Description
Dictionary<Type, IInstanceModel> map

The preconfigured type registrations to seed into the mocker.

Mocker(Dictionary<Type, IInstanceModel>, Action<LogLevel, EventId, string, Exception?>)

Initializes a new Mocker instance with an existing type map and an exception-aware logging callback.

Declaration
public Mocker(Dictionary<Type, IInstanceModel> map, Action<LogLevel, EventId, string, Exception?> loggingCallback)
Parameters
Type Name Description
Dictionary<Type, IInstanceModel> map

The preconfigured type registrations to seed into the mocker.
Action<LogLevel, EventId, string, Exception> loggingCallback

Callback invoked for log entries emitted by this mocker.

Mocker(Dictionary<Type, IInstanceModel>, Action<LogLevel, EventId, string>)

Initializes a new Mocker instance with an existing type map and a three-parameter logging callback.

Declaration
public Mocker(Dictionary<Type, IInstanceModel> map, Action<LogLevel, EventId, string> loggingCallback)
Parameters
Type Name Description
Dictionary<Type, IInstanceModel> map

The preconfigured type registrations to seed into the mocker.
Action<LogLevel, EventId, string> loggingCallback

Callback invoked for log entries emitted by this mocker.

Fields

creatingTypeList

Tracks types currently being created so recursive resolution can short-circuit circular member population.

Declaration
protected readonly List<Type> creatingTypeList
Field Value
Type Description
List<Type>

fileSystem

The shared in-memory file system used by built-in file-system resolution helpers.

Declaration
public readonly MockFileSystem fileSystem
Field Value
Type Description
MockFileSystem

mockCollection

Stores the tracked mock models for this Mocker instance.

Declaration
protected readonly List<MockModel> mockCollection
Field Value
Type Description
List<MockModel>

Properties

Behavior

Feature flag container controlling behavior such as base-call usage, dependency injection, nested member population, logging capture, and strict verification.

Declaration
public MockBehaviorOptions Behavior { get; set; }
Property Value
Type Description
MockBehaviorOptions

ConstructorHistory

Tracks constructor-selection history for created instances.

Declaration
public ConstructorHistory ConstructorHistory { get; }
Property Value
Type Description
ConstructorHistory

ExceptionLog

Captured exception messages observed during resolution and invocation helper flows.

Declaration
public ObservableExceptionLog ExceptionLog { get; }
Property Value
Type Description
ObservableExceptionLog

HttpClient

The shared HttpClient created for this mocker instance.

Declaration
public HttpClient HttpClient { get; }
Property Value
Type Description
HttpClient

LogEntries

Captured log entries observed through this mocker instance.

Declaration
public ObservableLogEntries LogEntries { get; }
Property Value
Type Description
ObservableLogEntries

LoggingCallback

Callback invoked when FastMoq captures a log entry through this mocker instance.

Declaration
public Action<LogLevel, EventId, string, Exception?> LoggingCallback { get; }
Property Value
Type Description
Action<LogLevel, EventId, string, Exception>

OptionalParameterResolution

Controls how optional constructor and invocation parameters are resolved when values are not supplied explicitly.

Declaration
public OptionalParameterResolutionMode OptionalParameterResolution { get; set; }
Property Value
Type Description
OptionalParameterResolutionMode

Policy

Policy settings that control built-in type resolution and constructor fallback behavior.

Declaration
public MockerPolicyOptions Policy { get; }
Property Value
Type Description
MockerPolicyOptions

Uri

The base URI associated with the shared HttpClient.

Declaration
public Uri Uri { get; }
Property Value
Type Description
Uri

Methods

AddFileSystemAbstractionMapping()

Registers the standard System.IO.Abstractions mappings backed by the current mock file system.

Declaration
public void AddFileSystemAbstractionMapping()

AddInjections<T>(T, Type?)

Populates injectable fields and properties on the supplied object using the current resolution pipeline.

Declaration
public T AddInjections<T>(T obj, Type? referenceType = null) where T : class?
Parameters
Type Name Description
T obj

The object whose injectable members should be populated.
Type referenceType

Optional type used to discover injectable members instead of the runtime type.
Returns
Type Description
T

The same object instance after injection.
Type Parameters
Name Description
T

The object type to update.

AddKeyedType(Type, object, Type, Func<Mocker, object>?, bool, params object?[]?)

Adds a keyed type registration for this Mocker instance.

Declaration
public Mocker AddKeyedType(Type tInterface, object serviceKey, Type tClass, Func<Mocker, object>? createFunc = null, bool replace = false, params object?[]? args)
Parameters
Type Name Description
Type tInterface
object serviceKey
Type tClass
Func<Mocker, object> createFunc
bool replace
object[] args
Returns
Type Description
Mocker

AddKeyedType<T>(object, Func<Mocker, T>?, bool, params object?[]?)

Adds a keyed concrete registration with factory for this Mocker instance.

Declaration
public Mocker AddKeyedType<T>(object serviceKey, Func<Mocker, T>? createFunc = null, bool replace = false, params object?[]? args) where T : class
Parameters
Type Name Description
object serviceKey
Func<Mocker, T> createFunc
bool replace
object[] args
Returns
Type Description
Mocker
Type Parameters
Name Description
T

AddKeyedType<T>(object, T, bool)

Adds a keyed concrete value for this Mocker instance.

Declaration
public Mocker AddKeyedType<T>(object serviceKey, T value, bool replace = false)
Parameters
Type Name Description
object serviceKey
T value
bool replace
Returns
Type Description
Mocker
Type Parameters
Name Description
T

AddKeyedType<TInterface, TClass>(object, bool, params object?[]?)

Adds a keyed interface-to-concrete registration for this Mocker instance.

Declaration
public Mocker AddKeyedType<TInterface, TClass>(object serviceKey, bool replace = false, params object?[]? args) where TInterface : class where TClass : class
Parameters
Type Name Description
object serviceKey
bool replace
object[] args
Returns
Type Description
Mocker
Type Parameters
Name Description
TInterface
TClass

AddKeyedType<TInterface, TClass>(object, Func<Mocker, TClass>?, bool, params object?[]?)

Adds a keyed interface-to-concrete registration with factory for this Mocker instance.

Declaration
public Mocker AddKeyedType<TInterface, TClass>(object serviceKey, Func<Mocker, TClass>? createFunc, bool replace = false, params object?[]? args) where TInterface : class where TClass : class
Parameters
Type Name Description
object serviceKey
Func<Mocker, TClass> createFunc
bool replace
object[] args
Returns
Type Description
Mocker
Type Parameters
Name Description
TInterface
TClass

AddKnownType(KnownTypeRegistration, bool)

Adds a custom known-type registration for this Mocker instance. This is the extensibility point for framework-like types that need special resolution or setup behavior.

Declaration
public Mocker AddKnownType(KnownTypeRegistration registration, bool replace = false)
Parameters
Type Name Description
KnownTypeRegistration registration
bool replace
Returns
Type Description
Mocker

AddKnownType<TKnown>(Func<Mocker, Type, TKnown?>?, Func<Mocker, Type, TKnown?>?, Action<Mocker, Type, IFastMock>?, Action<Mocker, TKnown>?, bool, bool)

Adds a typed custom known-type registration for this Mocker instance.

Declaration
public Mocker AddKnownType<TKnown>(Func<Mocker, Type, TKnown?>? directInstanceFactory = null, Func<Mocker, Type, TKnown?>? managedInstanceFactory = null, Action<Mocker, Type, IFastMock>? configureMock = null, Action<Mocker, TKnown>? applyObjectDefaults = null, bool includeDerivedTypes = false, bool replace = false)
Parameters
Type Name Description
Func<Mocker, Type, TKnown> directInstanceFactory
Func<Mocker, Type, TKnown> managedInstanceFactory
Action<Mocker, Type, IFastMock> configureMock
Action<Mocker, TKnown> applyObjectDefaults
bool includeDerivedTypes
bool replace
Returns
Type Description
Mocker
Type Parameters
Name Description
TKnown

AddProperties(Type, object?, params KeyValuePair<string, object>[])

Populates readable properties on an object using either explicit values or resolved dependencies.

Declaration
public object? AddProperties(Type type, object? obj, params KeyValuePair<string, object>[] data)
Parameters
Type Name Description
Type type
object obj
KeyValuePair<string, object>[] data
Returns
Type Description
object

AddProperties<T>(T, params KeyValuePair<string, object>[])

Populates readable properties on an object using either explicit values or resolved dependencies.

Declaration
public T? AddProperties<T>(T obj, params KeyValuePair<string, object>[] data)
Parameters
Type Name Description
T obj
KeyValuePair<string, object>[] data
Returns
Type Description
T
Type Parameters
Name Description
T

AddType(Type, Type, Func<Mocker, object>?, bool, params object?[]?)

Registers an interface-to-concrete mapping for object resolution.

Declaration
public Mocker AddType(Type tInterface, Type tClass, Func<Mocker, object>? createFunc = null, bool replace = false, params object?[]? args)
Parameters
Type Name Description
Type tInterface

The service or abstraction type to resolve.
Type tClass

The concrete implementation type to construct.
Func<Mocker, object> createFunc

Optional factory used instead of the default constructor path.
bool replace

True to replace an existing registration for the same service type.
object[] args

Optional constructor or factory arguments associated with the registration.
Returns
Type Description
Mocker

The current Mocker instance.

AddType<T>(Func<Mocker, T>?, bool, params object?[]?)

Registers a concrete type using an optional typed factory.

Declaration
public Mocker AddType<T>(Func<Mocker, T>? createFunc = null, bool replace = false, params object?[]? args) where T : class
Parameters
Type Name Description
Func<Mocker, T> createFunc
bool replace
object[] args
Returns
Type Description
Mocker
Type Parameters
Name Description
T

AddType<T>(T, bool)

Registers a concrete instance so future object resolution returns that instance instead of auto-creating a mock.

Declaration
public Mocker AddType<T>(T value, bool replace = false)
Parameters
Type Name Description
T value
bool replace
Returns
Type Description
Mocker
Type Parameters
Name Description
T
Examples

Use this overload when a dependency should be a known runtime object rather than a tracked mock.

var fileSystem = new MockFileSystem();

var mocker = new Mocker()
.AddType<IFileSystem>(fileSystem);


var resolvedFileSystem = mocker.GetRequiredObject<IFileSystem>();
resolvedFileSystem.Should().BeSameAs(fileSystem);

AddType<TInterface, TClass>(bool, params object?[]?)

Registers a type as its own implementation for future resolution.

Declaration
public Mocker AddType<TInterface, TClass>(bool replace = false, params object?[]? args) where TInterface : class where TClass : class
Parameters
Type Name Description
bool replace
object[] args
Returns
Type Description
Mocker
Type Parameters
Name Description
TInterface
TClass

AddType<TInterface, TClass>(Func<Mocker, TClass>?, bool, params object?[]?)

Registers a type mapping that uses a typed factory during resolution.

Declaration
public Mocker AddType<TInterface, TClass>(Func<Mocker, TClass>? createFunc, bool replace = false, params object?[]? args) where TInterface : class where TClass : class
Parameters
Type Name Description
Func<Mocker, TClass> createFunc
bool replace
object[] args
Returns
Type Description
Mocker
Type Parameters
Name Description
TInterface
TClass

BuildExpression<T>()

Builds a wildcard predicate expression for expression-valued arguments. Prefer AnyExpression<T>() in new code.

Declaration
public static Expression<Func<T, bool>> BuildExpression<T>()
Returns
Type Description
Expression<Func<T, bool>>
Type Parameters
Name Description
T

CallMethod(InvocationOptions?, Action, params object?[])

Invokes an action using the supplied invocation options.

Declaration
public void CallMethod(InvocationOptions? options, Action action, params object?[] args)
Parameters
Type Name Description
InvocationOptions options
Action action
object[] args

CallMethod(InvocationOptions?, Delegate, params object?[])

Invokes a delegate without using its return value and with explicit invocation options.

Declaration
public void CallMethod(InvocationOptions? options, Delegate del, params object?[] args)
Parameters
Type Name Description
InvocationOptions options
Delegate del
object[] args

CallMethod(Action, params object?[])

Invokes an action using the mocker's current invocation defaults.

Declaration
public void CallMethod(Action action, params object?[] args)
Parameters
Type Name Description
Action action
object[] args

CallMethod(Delegate, params object?[])

Invokes a delegate without using its return value.

Declaration
public void CallMethod(Delegate del, params object?[] args)
Parameters
Type Name Description
Delegate del
object[] args

CallMethodAsync<TReturn>(InvocationOptions?, Delegate, params object?[])

Invokes a delegate and awaits a task result using the supplied invocation options.

Declaration
public Task<TReturn> CallMethodAsync<TReturn>(InvocationOptions? options, Delegate del, params object?[] args)
Parameters
Type Name Description
InvocationOptions options
Delegate del
object[] args
Returns
Type Description
Task<TReturn>
Type Parameters
Name Description
TReturn

CallMethodAsync<TReturn>(Delegate, params object?[])

Invokes a delegate and awaits a task result using the mocker's current invocation defaults.

Declaration
public Task<TReturn> CallMethodAsync<TReturn>(Delegate del, params object?[] args)
Parameters
Type Name Description
Delegate del
object[] args
Returns
Type Description
Task<TReturn>
Type Parameters
Name Description
TReturn

CallMethod<TReturn>(InvocationOptions?, Delegate, params object?[])

Invokes a delegate and returns its result using the supplied invocation options.

Declaration
public TReturn CallMethod<TReturn>(InvocationOptions? options, Delegate del, params object?[] args)
Parameters
Type Name Description
InvocationOptions options
Delegate del
object[] args
Returns
Type Description
TReturn
Type Parameters
Name Description
TReturn

CallMethod<TReturn>(InvocationOptions?, Func<TReturn>, params object?[])

Invokes a function and returns its result using the supplied invocation options.

Declaration
public TReturn CallMethod<TReturn>(InvocationOptions? options, Func<TReturn> func, params object?[] args)
Parameters
Type Name Description
InvocationOptions options
Func<TReturn> func
object[] args
Returns
Type Description
TReturn
Type Parameters
Name Description
TReturn

CallMethod<TReturn>(Delegate, params object?[])

Invokes a delegate and returns its result using the mocker's current invocation defaults.

Declaration
public TReturn CallMethod<TReturn>(Delegate del, params object?[] args)
Parameters
Type Name Description
Delegate del
object[] args
Returns
Type Description
TReturn
Type Parameters
Name Description
TReturn

CallMethod<TReturn>(Func<TReturn>, params object?[])

Invokes a function and returns its result using the mocker's current invocation defaults.

Declaration
public TReturn CallMethod<TReturn>(Func<TReturn> func, params object?[] args)
Parameters
Type Name Description
Func<TReturn> func
object[] args
Returns
Type Description
TReturn
Type Parameters
Name Description
TReturn

CreateFastMock<T>(MockCreationOptions?)

Creates a provider-first mock and registers it.

Declaration
public IFastMock<T> CreateFastMock<T>(MockCreationOptions? options = null) where T : class
Parameters
Type Name Description
MockCreationOptions options
Returns
Type Description
IFastMock<T>
Type Parameters
Name Description
T

CreateInstanceByType<T>(InstanceCreationFlags, params Type?[])

Creates an instance of T by selecting a constructor that matches the supplied parameter types and creation flags.

Declaration
public T? CreateInstanceByType<T>(InstanceCreationFlags flags, params Type?[] parameterTypes) where T : class
Parameters
Type Name Description
InstanceCreationFlags flags
Type[] parameterTypes
Returns
Type Description
T
Type Parameters
Name Description
T

CreateInstanceByType<T>(params Type?[])

Creates an instance of T by selecting a constructor that matches the supplied parameter types.

Declaration
public T? CreateInstanceByType<T>(params Type?[] parameterTypes) where T : class
Parameters
Type Name Description
Type[] parameterTypes
Returns
Type Description
T
Type Parameters
Name Description
T

CreateInstance<T>(InstanceCreationFlags, params object?[])

Creates an instance of T using the supplied per-call construction flags.

Declaration
public T? CreateInstance<T>(InstanceCreationFlags flags, params object?[] args) where T : class
Parameters
Type Name Description
InstanceCreationFlags flags
object[] args
Returns
Type Description
T
Type Parameters
Name Description
T

CreateInstance<T>(params object?[])

Creates an instance of T using the current component-construction defaults.

Declaration
public T? CreateInstance<T>(params object?[] args) where T : class
Parameters
Type Name Description
object[] args
Returns
Type Description
T
Type Parameters
Name Description
T

CreateStandaloneFastMock(Type, MockCreationOptions?)

Creates a provider-first mock handle for the supplied runtime type without registering it into this Mocker instance.

Declaration
public IFastMock CreateStandaloneFastMock(Type type, MockCreationOptions? options = null)
Parameters
Type Name Description
Type type
MockCreationOptions options
Returns
Type Description
IFastMock
Remarks

Use this when the test needs a provider-selected standalone mock handle but does not want the mock tracked by the parent Mocker.

CreateStandaloneFastMock<T>(MockCreationOptions?)

Creates a provider-first mock handle without registering it into this Mocker instance.

Declaration
public IFastMock<T> CreateStandaloneFastMock<T>(MockCreationOptions? options = null) where T : class
Parameters
Type Name Description
MockCreationOptions options
Returns
Type Description
IFastMock<T>
Type Parameters
Name Description
T
Remarks

Use this when the test needs an additional independent mock of the same service type, or when the mock will be wired manually instead of tracked through GetOrCreateMock<T>(MockRequestOptions?). Provider selection still flows through Default, but the returned handle is not added to the parent tracked mock collection.

Dispose()

Releases helper-owned disposable registrations created by this Mocker instance.

Declaration
public void Dispose()

Dispose(bool)

Releases managed resources owned by this Mocker instance. Derived types overriding this method should call the base implementation.

Declaration
protected virtual void Dispose(bool disposing)
Parameters
Type Name Description
bool disposing

true when called from Dispose(); otherwise, false.

DisposeAsync()

Asynchronously releases helper-owned disposable registrations created by this Mocker instance.

Declaration
public ValueTask DisposeAsync()
Returns
Type Description
ValueTask

A task that completes when owned registrations are disposed.

DisposeAsyncCore()

Asynchronously releases resources owned by this Mocker instance. Derived types overriding this method should call the base implementation.

Declaration
protected virtual ValueTask DisposeAsyncCore()
Returns
Type Description
ValueTask

A task that completes when asynchronous cleanup has finished.

GetArgData<T>()

Builds constructor argument data for T using the mocker's current optional-parameter policy.

Declaration
public object?[] GetArgData<T>() where T : class
Returns
Type Description
object[]
Type Parameters
Name Description
T

GetArgData<T>(InstanceCreationFlags)

Builds constructor argument data for T using the supplied creation flags.

Declaration
public object?[] GetArgData<T>(InstanceCreationFlags flags) where T : class
Parameters
Type Name Description
InstanceCreationFlags flags
Returns
Type Description
object[]
Type Parameters
Name Description
T

GetArgData<T>(OptionalParameterResolutionMode)

Builds constructor argument data for T using the supplied optional-parameter policy.

Declaration
public object?[] GetArgData<T>(OptionalParameterResolutionMode optionalParameterResolution) where T : class
Parameters
Type Name Description
OptionalParameterResolutionMode optionalParameterResolution
Returns
Type Description
object[]
Type Parameters
Name Description
T

GetFileSystem()

Returns the shared mock file system.

Declaration
public IFileSystem GetFileSystem()
Returns
Type Description
IFileSystem

GetFileSystem(Action<MockFileSystem>?)

Returns the shared mock file system after optionally applying additional configuration.

Declaration
public IFileSystem GetFileSystem(Action<MockFileSystem>? configure = null)
Parameters
Type Name Description
Action<MockFileSystem> configure
Returns
Type Description
IFileSystem

GetKeyedObject(Type, object, Action<object?>?)

Resolves a keyed object for the specified service type.

Declaration
public object? GetKeyedObject(Type type, object serviceKey, Action<object?>? initAction = null)
Parameters
Type Name Description
Type type
object serviceKey
Action<object> initAction
Returns
Type Description
object

GetKeyedObject<T>(object)

Resolves a keyed object using the supplied service key.

Declaration
public T? GetKeyedObject<T>(object serviceKey) where T : class
Parameters
Type Name Description
object serviceKey
Returns
Type Description
T
Type Parameters
Name Description
T

GetKeyedObject<T>(object, Action<T?>)

Resolves a keyed object and invokes an initialization callback with the typed result.

Declaration
public T? GetKeyedObject<T>(object serviceKey, Action<T?> init) where T : class
Parameters
Type Name Description
object serviceKey
Action<T> init
Returns
Type Description
T
Type Parameters
Name Description
T

GetList<T>(int, Func<int, T>)

Creates a list by invoking the supplied indexed factory a fixed number of times.

Declaration
public static List<T> GetList<T>(int count, Func<int, T> factory)
Parameters
Type Name Description
int count
Func<int, T> factory
Returns
Type Description
List<T>
Type Parameters
Name Description
T

GetList<T>(int, Func<int, T>, Action<int, T>)

Creates a list by invoking the supplied indexed factory and initializer a fixed number of times.

Declaration
public static List<T> GetList<T>(int count, Func<int, T> factory, Action<int, T> init)
Parameters
Type Name Description
int count
Func<int, T> factory
Action<int, T> init
Returns
Type Description
List<T>
Type Parameters
Name Description
T

GetList<T>(int, Func<T>)

Creates a list by invoking the supplied factory a fixed number of times.

Declaration
public static List<T> GetList<T>(int count, Func<T> factory)
Parameters
Type Name Description
int count
Func<T> factory
Returns
Type Description
List<T>
Type Parameters
Name Description
T

GetMethodArgData(MethodBase?)

Builds invocation arguments for a method using the mocker's current optional-parameter policy.

Declaration
public object?[] GetMethodArgData(MethodBase? method)
Parameters
Type Name Description
MethodBase method
Returns
Type Description
object[]

GetMethodArgData(MethodBase?, InvocationOptions?)

Builds invocation arguments for a method using the supplied invocation options.

Declaration
public object?[] GetMethodArgData(MethodBase? method, InvocationOptions? options)
Parameters
Type Name Description
MethodBase method
InvocationOptions options
Returns
Type Description
object[]

GetMethodDefaultData(MethodBase?)

Builds invocation arguments that contain only default values for the supplied method.

Declaration
public object?[] GetMethodDefaultData(MethodBase? method)
Parameters
Type Name Description
MethodBase method
Returns
Type Description
object[]

GetMockModel<T>()

Gets the tracked mock model for the supplied type parameter.

Declaration
public MockModel<T> GetMockModel<T>() where T : class
Returns
Type Description
MockModel<T>
Type Parameters
Name Description
T

GetNativeMock(Type)

Gets the provider-native mock object for the supplied runtime type. Prefer GetOrCreateMock(Type, MockRequestOptions?) plus provider-typed escape hatches when the test intentionally needs provider-specific APIs, and prefer GetObject(Type, Action<object?>?) or GetOrCreateMock(Type, MockRequestOptions?) for provider-first flows.

Declaration
public object GetNativeMock(Type type)
Parameters
Type Name Description
Type type
Returns
Type Description
object

GetNativeMock<T>(params object?[])

Gets the provider-native mock object for the supplied type parameter. Prefer GetOrCreateMock<T>(MockRequestOptions?) plus provider-typed escape hatches such as AsMoq() or AsNSubstitute() when the test intentionally needs a provider-specific API surface.

Declaration
public object GetNativeMock<T>(params object?[] args) where T : class
Parameters
Type Name Description
object[] args
Returns
Type Description
object
Type Parameters
Name Description
T

GetObject(ParameterInfo)

Resolves a value for the supplied parameter using the mocker's constructor and object-resolution rules.

Declaration
public object? GetObject(ParameterInfo info)
Parameters
Type Name Description
ParameterInfo info

The parameter to resolve.
Returns
Type Description
object

The resolved value, or the parameter type default when resolution fails.

GetObject(Type, Action<object?>?)

Resolves an object using custom registrations, known types, tracked mocks, and default fallbacks.

Declaration
public object? GetObject(Type type, Action<object?>? initAction = null)
Parameters
Type Name Description
Type type

The requested service or concrete type.
Action<object> initAction

Optional callback invoked with the resolved value before it is returned.
Returns
Type Description
object

The resolved object instance, or the type default when no value can be created.

GetObject<T>()

Resolves an object using FastMoq's runtime resolution pipeline.

Declaration
public T? GetObject<T>() where T : class
Returns
Type Description
T
Type Parameters
Name Description
T
Examples

Use GetObject<T>() when older code only needed GetMock<T>().Object and does not need the tracked mock handle itself.

var mocker = new Mocker();
var gateway = mocker.GetObject<IOrderGateway>();

Resolve a dependency after configuring a concrete registration through the provider-first pipeline.

var fileSystem = new MockFileSystem();
fileSystem.AddDirectory(@"c:\exports");

var mocker = new Mocker()
.AddType<IFileSystem>(fileSystem);


var resolvedFileSystem = mocker.GetRequiredObject<IFileSystem>();


resolvedFileSystem.Directory.Exists(@"c:\exports").Should().BeTrue();

GetObject<T>(Action<T?>)

Resolves an object and invokes an initialization callback with the typed result.

Declaration
public T? GetObject<T>(Action<T?> init) where T : class
Parameters
Type Name Description
Action<T> init
Returns
Type Description
T
Type Parameters
Name Description
T

GetObject<T>(object?[])

Creates an instance of T using the supplied constructor arguments.

Declaration
public T? GetObject<T>(object?[] args) where T : class
Parameters
Type Name Description
object[] args
Returns
Type Description
T
Type Parameters
Name Description
T

GetOrCreateMock(Type, MockRequestOptions?)

Gets an existing tracked provider-backed mock or creates and tracks one when it does not yet exist. Use the returned IFastMock when the test needs the tracked handle itself, and prefer GetObject(Type, Action<object?>?) when only the instance is needed.

Declaration
public IFastMock GetOrCreateMock(Type type, MockRequestOptions? options = null)
Parameters
Type Name Description
Type type
MockRequestOptions options
Returns
Type Description
IFastMock

GetOrCreateMockWithConstructorArgs(Type, params object?[])

Gets an existing tracked provider-backed mock or creates and tracks one when it does not yet exist, using the supplied constructor arguments for concrete mock creation.

Declaration
public IFastMock GetOrCreateMockWithConstructorArgs(Type type, params object?[] constructorArgs)
Parameters
Type Name Description
Type type
object[] constructorArgs
Returns
Type Description
IFastMock
Remarks

This is a convenience wrapper for GetOrCreateMock(Type, MockRequestOptions?) when the request only needs constructor arguments. Use GetOrCreateMock(Type, MockRequestOptions?) when also setting a service key or non-public constructor behavior.

GetOrCreateMockWithConstructorArgs<T>(params object?[])

Gets an existing tracked provider-backed mock or creates and tracks one when it does not yet exist, using the supplied constructor arguments for concrete mock creation.

Declaration
public IFastMock<T> GetOrCreateMockWithConstructorArgs<T>(params object?[] constructorArgs) where T : class
Parameters
Type Name Description
object[] constructorArgs
Returns
Type Description
IFastMock<T>
Type Parameters
Name Description
T
Remarks

This is a convenience wrapper for GetOrCreateMock<T>(MockRequestOptions?) when the request only needs constructor arguments. Use GetOrCreateMock<T>(MockRequestOptions?) when also setting a service key or non-public constructor behavior.

GetOrCreateMock<T>(MockRequestOptions?)

Gets an existing tracked provider-backed mock or creates and tracks one when it does not yet exist.

Declaration
public IFastMock<T> GetOrCreateMock<T>(MockRequestOptions? options = null) where T : class
Parameters
Type Name Description
MockRequestOptions options
Returns
Type Description
IFastMock<T>
Type Parameters
Name Description
T
Examples

Use GetOrCreateMock<T>(MockRequestOptions?) when the test needs the tracked mock handle itself, not just automatic constructor resolution.

fastMock.Instance is the provider-first replacement for older GetMock<T>().Object access when the test still wants the tracked handle.

GetOrCreateMock uses the active FastMoq provider. It does not require the Moq provider to be selected unless the test later calls Moq-specific extensions such as AsMoq(), Setup(...), or Protected().

var mocker = new Mocker();
var gateway = mocker.GetOrCreateMock<IOrderGateway>();

var submitter = new OrderSubmitter(gateway.Instance);
submitter.Submit(42);


mocker.Verify<IOrderGateway>(x => x.Publish(42), TimesSpec.Once);
mocker.VerifyNoOtherCalls<IOrderGateway>();

Provider-neutral usage works the same way under the reflection provider because the tracked handle is still an IFastMock<T>.

using var providerScope = MockingProviderRegistry.Push("reflection");

var mocker = new Mocker();
var dependency = mocker.GetOrCreateMock<IOrderGateway>();


var submitter = new OrderSubmitter(dependency.Instance);
submitter.Submit(42);


mocker.Verify<IOrderGateway>(x => x.Publish(42), TimesSpec.Once);

Typical reasons to call it explicitly are: passing Instance into custom component construction, reusing the same tracked mock across calls, resetting it, or using keyed MockRequestOptions. If the test needs Moq-specific setup or verification APIs, select the Moq provider for that test assembly before calling those extensions.

GetRequiredObject<T>()

Resolves a required object and throws when no instance can be produced.

Declaration
public T GetRequiredObject<T>() where T : class
Returns
Type Description
T
Type Parameters
Name Description
T

GetRequiredTrackedMock(Type)

Gets an already tracked provider-backed mock for the supplied runtime type and throws when no tracked mock exists.

Declaration
public IFastMock GetRequiredTrackedMock(Type type)
Parameters
Type Name Description
Type type
Returns
Type Description
IFastMock

GetRequiredTrackedMock(Type, object)

Gets an already tracked keyed provider-backed mock for the supplied runtime type and throws when no tracked mock exists for the supplied service key.

Declaration
public IFastMock GetRequiredTrackedMock(Type type, object serviceKey)
Parameters
Type Name Description
Type type
object serviceKey
Returns
Type Description
IFastMock

GetRequiredTrackedMock<T>()

Gets an already tracked provider-backed mock and throws when no tracked mock exists.

Declaration
public IFastMock<T> GetRequiredTrackedMock<T>() where T : class
Returns
Type Description
IFastMock<T>
Type Parameters
Name Description
T

GetRequiredTrackedMock<T>(object)

Gets an already tracked keyed provider-backed mock and throws when no tracked mock exists for the supplied service key.

Declaration
public IFastMock<T> GetRequiredTrackedMock<T>(object serviceKey) where T : class
Parameters
Type Name Description
object serviceKey
Returns
Type Description
IFastMock<T>
Type Parameters
Name Description
T

GetStringContent(HttpContent?)

Reads the string content from an HttpContent instance, returning an empty string when the content is null.

Declaration
public Task<string> GetStringContent(HttpContent? content)
Parameters
Type Name Description
HttpContent content
Returns
Type Description
Task<string>

HasParameterlessConstructor(Type, bool)

Determines whether the supplied type exposes a parameterless constructor.

Declaration
public bool HasParameterlessConstructor(Type type, bool nonPublic = false)
Parameters
Type Name Description
Type type
bool nonPublic
Returns
Type Description
bool

InvokeMethod(InvocationOptions?, object?, string, bool, params object?[])

Invokes a method on the supplied instance using the supplied invocation options.

Declaration
public object? InvokeMethod(InvocationOptions? options, object? instance, string methodName, bool nonPublic = false, params object?[] args)
Parameters
Type Name Description
InvocationOptions options
object instance
string methodName
bool nonPublic
object[] args
Returns
Type Description
object

InvokeMethod(object?, string, bool, params object?[])

Invokes a method on the supplied instance using the mocker's current invocation defaults.

Declaration
public object? InvokeMethod(object? instance, string methodName, bool nonPublic = false, params object?[] args)
Parameters
Type Name Description
object instance
string methodName
bool nonPublic
object[] args
Returns
Type Description
object

InvokeMethod<T>(InvocationOptions?, object?, string, bool, params object?[])

Invokes a method declared on T using the supplied invocation options.

Declaration
public object? InvokeMethod<T>(InvocationOptions? options, object? instance, string methodName, bool nonPublic = false, params object?[] args)
Parameters
Type Name Description
InvocationOptions options
object instance
string methodName
bool nonPublic
object[] args
Returns
Type Description
object
Type Parameters
Name Description
T

InvokeMethod<T>(InvocationOptions?, string, bool, params object?[])

Invokes a method declared on T without an explicit instance parameter using the supplied invocation options.

Declaration
public object? InvokeMethod<T>(InvocationOptions? options, string methodName, bool nonPublic = false, params object?[] args)
Parameters
Type Name Description
InvocationOptions options
string methodName
bool nonPublic
object[] args
Returns
Type Description
object
Type Parameters
Name Description
T

InvokeMethod<T>(object?, string, bool, params object?[])

Invokes a method declared on T using the mocker's current invocation defaults.

Declaration
public object? InvokeMethod<T>(object? instance, string methodName, bool nonPublic = false, params object?[] args)
Parameters
Type Name Description
object instance
string methodName
bool nonPublic
object[] args
Returns
Type Description
object
Type Parameters
Name Description
T

InvokeMethod<T>(string, bool, params object?[])

Invokes a method declared on T without an explicit instance parameter.

Declaration
public object? InvokeMethod<T>(string methodName, bool nonPublic = false, params object?[] args)
Parameters
Type Name Description
string methodName
bool nonPublic
object[] args
Returns
Type Description
object
Type Parameters
Name Description
T

Scenario<T>(T?)

Creates a new fluent scenario builder for the specified component type using provider-first creation.

Declaration
public ScenarioBuilder<T> Scenario<T>(T? instance = null) where T : class
Parameters
Type Name Description
T instance
Returns
Type Description
ScenarioBuilder<T>
Type Parameters
Name Description
T

TryGetTrackedMock(Type, out IFastMock?)

Attempts to get an already tracked provider-backed mock for the supplied runtime type without creating one.

Declaration
public bool TryGetTrackedMock(Type type, out IFastMock? mock)
Parameters
Type Name Description
Type type
IFastMock mock
Returns
Type Description
bool

TryGetTrackedMock(Type, object, out IFastMock?)

Attempts to get an already tracked keyed provider-backed mock for the supplied runtime type without creating one.

Declaration
public bool TryGetTrackedMock(Type type, object serviceKey, out IFastMock? mock)
Parameters
Type Name Description
Type type
object serviceKey
IFastMock mock
Returns
Type Description
bool

TryGetTrackedMock<T>(out IFastMock<T>?)

Attempts to get an already tracked provider-backed mock without creating one.

Declaration
public bool TryGetTrackedMock<T>(out IFastMock<T>? mock) where T : class
Parameters
Type Name Description
IFastMock<T> mock
Returns
Type Description
bool
Type Parameters
Name Description
T

TryGetTrackedMock<T>(object, out IFastMock<T>?)

Attempts to get an already tracked keyed provider-backed mock without creating one.

Declaration
public bool TryGetTrackedMock<T>(object serviceKey, out IFastMock<T>? mock) where T : class
Parameters
Type Name Description
object serviceKey
IFastMock<T> mock
Returns
Type Description
bool
Type Parameters
Name Description
T

UseLenientPreset()

Applies the predefined lenient behavior preset. This is broader than disabling FailOnUnconfigured alone.

Declaration
public void UseLenientPreset()

UseStrictPreset()

Applies the predefined strict behavior preset. This is broader than FastMoq.Mocker.Strict, which is retained for backward compatibility.

Declaration
public void UseStrictPreset()

VerifyAnyArgs<T>(string, TimesSpec?, params Type[])

Verifies calls to the named method while treating every argument as a wildcard matcher.

Declaration
public void VerifyAnyArgs<T>(string methodName, TimesSpec? times = null, params Type[] parameterTypes) where T : class
Parameters
Type Name Description
string methodName

The instance method name to verify.
TimesSpec? times

The expected invocation count. When omitted, the helper expects at least one matching call.
Type[] parameterTypes

Optional parameter types used to disambiguate overloaded methods.
Type Parameters
Name Description
T

The tracked mock type to verify.
Remarks

Use this helper when a provider-neutral verification would otherwise require a long list of repeated Any<T>() markers. If the target method is overloaded, supply parameterTypes to choose the intended signature explicitly.

VerifyAnyArgs<T, TDelegate>(Func<T, TDelegate>, TimesSpec?)

Verifies calls to the selected method while treating every argument as a wildcard matcher.

Declaration
public void VerifyAnyArgs<T, TDelegate>(Func<T, TDelegate> methodSelector, TimesSpec? times = null) where T : class where TDelegate : Delegate
Parameters
Type Name Description
Func<T, TDelegate> methodSelector

A method-group selector such as x => x.Publish.
TimesSpec? times

The expected invocation count. When omitted, the helper expects at least one matching call.
Type Parameters
Name Description
T

The tracked mock type to verify.
TDelegate

The delegate type used to identify the selected method.
Remarks

Prefer this overload when the method is not overloaded and you want compiler-verified member selection. For overloaded methods, use VerifyAnyArgs<T>(string, TimesSpec?, params Type[]) with explicit parameter types.

VerifyCalledAtLeastAnyArgs<T>(string, int, params Type[])

Verifies that the named method was called at least the supplied number of times while treating every argument as a wildcard matcher.

Declaration
public void VerifyCalledAtLeastAnyArgs<T>(string methodName, int times, params Type[] parameterTypes) where T : class
Parameters
Type Name Description
string methodName
int times
Type[] parameterTypes
Type Parameters
Name Description
T

VerifyCalledAtLeastAnyArgs<T, TDelegate>(Func<T, TDelegate>, int)

Verifies that the selected method was called at least the supplied number of times while treating every argument as a wildcard matcher.

Declaration
public void VerifyCalledAtLeastAnyArgs<T, TDelegate>(Func<T, TDelegate> methodSelector, int times) where T : class where TDelegate : Delegate
Parameters
Type Name Description
Func<T, TDelegate> methodSelector
int times
Type Parameters
Name Description
T
TDelegate

VerifyCalledAtLeast<T>(Expression<Action<T>>, int)

Verifies that the specified invocation occurred at least the supplied number of times on the tracked mock.

Declaration
public void VerifyCalledAtLeast<T>(Expression<Action<T>> expression, int times) where T : class
Parameters
Type Name Description
Expression<Action<T>> expression
int times
Type Parameters
Name Description
T

VerifyCalledAtMostAnyArgs<T>(string, int, params Type[])

Verifies that the named method was called at most the supplied number of times while treating every argument as a wildcard matcher.

Declaration
public void VerifyCalledAtMostAnyArgs<T>(string methodName, int times, params Type[] parameterTypes) where T : class
Parameters
Type Name Description
string methodName
int times
Type[] parameterTypes
Type Parameters
Name Description
T

VerifyCalledAtMostAnyArgs<T, TDelegate>(Func<T, TDelegate>, int)

Verifies that the selected method was called at most the supplied number of times while treating every argument as a wildcard matcher.

Declaration
public void VerifyCalledAtMostAnyArgs<T, TDelegate>(Func<T, TDelegate> methodSelector, int times) where T : class where TDelegate : Delegate
Parameters
Type Name Description
Func<T, TDelegate> methodSelector
int times
Type Parameters
Name Description
T
TDelegate

VerifyCalledAtMost<T>(Expression<Action<T>>, int)

Verifies that the specified invocation occurred at most the supplied number of times on the tracked mock.

Declaration
public void VerifyCalledAtMost<T>(Expression<Action<T>> expression, int times) where T : class
Parameters
Type Name Description
Expression<Action<T>> expression
int times
Type Parameters
Name Description
T

VerifyCalledExactlyAnyArgs<T>(string, int, params Type[])

Verifies that the named method was called exactly the supplied number of times while treating every argument as a wildcard matcher.

Declaration
public void VerifyCalledExactlyAnyArgs<T>(string methodName, int times, params Type[] parameterTypes) where T : class
Parameters
Type Name Description
string methodName
int times
Type[] parameterTypes
Type Parameters
Name Description
T

VerifyCalledExactlyAnyArgs<T, TDelegate>(Func<T, TDelegate>, int)

Verifies that the selected method was called exactly the supplied number of times while treating every argument as a wildcard matcher.

Declaration
public void VerifyCalledExactlyAnyArgs<T, TDelegate>(Func<T, TDelegate> methodSelector, int times) where T : class where TDelegate : Delegate
Parameters
Type Name Description
Func<T, TDelegate> methodSelector
int times
Type Parameters
Name Description
T
TDelegate

VerifyCalledExactly<T>(Expression<Action<T>>, int)

Verifies that the specified invocation occurred exactly the supplied number of times on the tracked mock.

Declaration
public void VerifyCalledExactly<T>(Expression<Action<T>> expression, int times) where T : class
Parameters
Type Name Description
Expression<Action<T>> expression
int times
Type Parameters
Name Description
T

VerifyCalledOnceAnyArgs<T>(string, params Type[])

Verifies that the named method was called exactly once while treating every argument as a wildcard matcher.

Declaration
public void VerifyCalledOnceAnyArgs<T>(string methodName, params Type[] parameterTypes) where T : class
Parameters
Type Name Description
string methodName
Type[] parameterTypes
Type Parameters
Name Description
T

VerifyCalledOnceAnyArgs<T, TDelegate>(Func<T, TDelegate>)

Verifies that the selected method was called exactly once while treating every argument as a wildcard matcher.

Declaration
public void VerifyCalledOnceAnyArgs<T, TDelegate>(Func<T, TDelegate> methodSelector) where T : class where TDelegate : Delegate
Parameters
Type Name Description
Func<T, TDelegate> methodSelector
Type Parameters
Name Description
T
TDelegate

VerifyCalledOnce<T>(Expression<Action<T>>)

Verifies that the specified invocation occurred exactly once on the tracked mock.

Declaration
public void VerifyCalledOnce<T>(Expression<Action<T>> expression) where T : class
Parameters
Type Name Description
Expression<Action<T>> expression
Type Parameters
Name Description
T

VerifyNoOtherCalls<T>()

Ensures no other calls were made for a given mock (provider-first only).

Declaration
public void VerifyNoOtherCalls<T>() where T : class
Type Parameters
Name Description
T

VerifyNotCalledAnyArgs<T>(string, params Type[])

Verifies that the named method was never called while treating every argument as a wildcard matcher.

Declaration
public void VerifyNotCalledAnyArgs<T>(string methodName, params Type[] parameterTypes) where T : class
Parameters
Type Name Description
string methodName
Type[] parameterTypes
Type Parameters
Name Description
T

VerifyNotCalledAnyArgs<T, TDelegate>(Func<T, TDelegate>)

Verifies that the selected method was never called while treating every argument as a wildcard matcher.

Declaration
public void VerifyNotCalledAnyArgs<T, TDelegate>(Func<T, TDelegate> methodSelector) where T : class where TDelegate : Delegate
Parameters
Type Name Description
Func<T, TDelegate> methodSelector
Type Parameters
Name Description
T
TDelegate

VerifyNotCalled<T>(Expression<Action<T>>)

Verifies that the specified invocation never occurred on the tracked mock.

Declaration
public void VerifyNotCalled<T>(Expression<Action<T>> expression) where T : class
Parameters
Type Name Description
Expression<Action<T>> expression
Type Parameters
Name Description
T

Verify<T>(Expression<Action<T>>, TimesSpec?)

Provider-first verification helper (provider agnostic).

Declaration
public void Verify<T>(Expression<Action<T>> expression, TimesSpec? times = null) where T : class
Parameters
Type Name Description
Expression<Action<T>> expression
TimesSpec? times
Type Parameters
Name Description
T

Implements

Extension Methods