API Reference

Complete reference for all public classes and methods in the CosmosDB.InMemoryEmulator packages.

See also: Getting Started · Choosing Your Approach · Setup Guide · SQL Queries · Known Limitations

Package: CosmosDB.InMemoryEmulator

`InMemoryCosmos` (Static)

Entry point for creating in-memory Cosmos DB test infrastructure. New in 3.0.0.

Member	Type	Description
`DefaultDatabaseName`	`string`	`"default"` — default database for `AddContainer()`

Method	Returns	Description
`Create(containerName, partitionKeyPath, ...)`	`InMemoryCosmosResult`	Single-container setup (one-liner)
`Create(containerName, partitionKeyPaths, ...)`	`InMemoryCosmosResult`	Single-container with hierarchical PK
`Builder()`	`InMemoryCosmosBuilder`	Multi-container/advanced builder

`InMemoryCosmosBuilder`

Method	Returns	Description
`AddContainer(name, pkPath, configure?)`	`InMemoryCosmosBuilder`	Add container to default database
`AddContainer(name, pkPaths, configure?)`	`InMemoryCosmosBuilder`	Add container with hierarchical PK
`AddDatabase(dbName, configure)`	`InMemoryCosmosBuilder`	Add a named database with containers
`WrapHandler(wrapper)`	`InMemoryCosmosBuilder`	Add HTTP handler wrapper
`ConfigureOptions(configure)`	`InMemoryCosmosBuilder`	Configure `CosmosClientOptions`
`Build()`	`InMemoryCosmosResult`	Build the setup

`InMemoryCosmosResult` : `IDisposable`, `IAsyncDisposable`

Member	Type	Description
`Client`	`CosmosClient`	The in-memory-backed `CosmosClient`
`Container`	`Container`	SDK Container (single-container only)
`Containers`	`IReadOnlyDictionary<string, Container>`	All SDK Containers by name
`Handler`	`FakeCosmosHandler`	Handler (single-container only)
`Handlers`	`IReadOnlyDictionary<string, FakeCosmosHandler>`	All handlers by name

Method	Returns	Description
`SetupContainer(name?)`	`IContainerTestSetup`	Test setup for a container (registration)
`GetHandler(name)`	`FakeCosmosHandler`	Handler for a named container
`SetFaultInjector(injector)`	`void`	Set/clear fault injector on all handlers
`Database(dbName)`	`InMemoryDatabaseResult`	Database-scoped access
`Databases`	`IReadOnlyDictionary<string, InMemoryDatabaseResult>`	All databases
`ExportState(name?)`	`string`	Export container state as JSON
`ExportStateToFile(path, name?)`	`void`	Export container state to a file
`ImportState(json, name?)`	`void`	Import container state from JSON
`ImportStateFromFile(filePath, name?)`	`void`	Import container state from a file
`RestoreToPointInTime(timestamp, name?)`	`void`	Restore container to a point in time
`ClearItems(name?)`	`void`	Remove all items from the container

`InMemoryDatabaseResult`

Member	Type	Description
`DatabaseName`	`string`	The database name
`Containers`	`IReadOnlyDictionary<string, Container>`	Containers in this database
`Handlers`	`IReadOnlyDictionary<string, FakeCosmosHandler>`	Handlers in this database

Method	Returns	Description
`SetupContainer(name)`	`IContainerTestSetup`	Test setup for a container in this database
`GetHandler(name)`	`FakeCosmosHandler`	Handler for a container in this database
`SetFaultInjector(injector)`	`void`	Set/clear fault injector on this database's handlers
`ExportState(name)`	`string`	Export container state as JSON
`ExportStateToFile(name, path)`	`void`	Export container state to a file
`ImportState(name, json)`	`void`	Import container state from JSON
`ImportStateFromFile(name, filePath)`	`void`	Import container state from a file
`RestoreToPointInTime(name, timestamp)`	`void`	Restore container to a point in time
`ClearItems(name)`	`void`	Remove all items from the container

`IContainerTestSetup`

Focused interface for test-only operations. Implemented by InMemoryContainer.

Method	Returns	Description
`RegisterStoredProcedure(name, handler)`	`void`	Register C# stored procedure
`RegisterStoredProcedure(name, jsBody)`	`void`	Register JS stored procedure (requires JsTriggers package)
`RegisterUdf(name, handler)`	`void`	Register C# UDF
`RegisterUdf(name, jsBody)`	`void`	Register JS UDF (requires JsTriggers package)
`RegisterTrigger(name, type, operation, handler)`	`void`	Register C# trigger
`RegisterTrigger(name, type, operation, jsBody)`	`void`	Register JS trigger (requires JsTriggers package)
`ExportState()`	`string`	Export container state as JSON
`ExportStateToFile(path)`	`void`	Export container state to a file
`ImportState(json)`	`void`	Import container state from JSON
`ImportStateFromFile(filePath)`	`void`	Import container state from a file
`RestoreToPointInTime(timestamp)`	`void`	Restore container to a point in time via change feed replay
`ClearItems()`	`void`	Remove all items from the container

`InMemoryContainer`

In-memory implementation of Container. The primary class for most testing scenarios.

Namespace: CosmosDB.InMemoryEmulator
Inherits: Microsoft.Azure.Cosmos.Container

Constructors

// Single partition key
InMemoryContainer(string id = "in-memory-container", string partitionKeyPath = "/id")

// Composite partition keys
InMemoryContainer(string id, IReadOnlyList<string> partitionKeyPaths)

// With container properties (unique key policies, etc.)
InMemoryContainer(ContainerProperties containerProperties)

Properties

Property	Type	Description
`Id`	`string`	Container identifier
`Database`	`Database`	Stubbed Database instance
`Conflicts`	`Conflicts`	Stubbed Conflicts instance
`Scripts`	`Scripts`	For stored procedure/UDF execution
`DefaultTimeToLive`	`int?`	Container-level TTL in seconds
`PartitionKeyPaths`	`IReadOnlyList<string>`	Partition key path(s)
`FeedRangeCount`	`int`	Number of feed ranges (default 1). Set > 1 to simulate multiple physical partitions
`MaxChangeFeedSize`	`int`	Maximum change feed entries retained (default 1000). When exceeded, oldest entries are evicted. Set to `0` for unbounded growth
`ItemCount`	`int`	Number of items currently stored
`IndexingPolicy`	`IndexingPolicy`	Accepted but does not affect query behaviour
`JsTriggerEngine`	`IJsTriggerEngine`	JavaScript trigger engine. Set via `.UseJsTriggers()` from the JsTriggers package, or assign a custom implementation
`StateFilePath`	`string`	Path for automatic state persistence. Set before calling `LoadPersistedState()` / `Dispose()`. See State Persistence

CRUD Methods (Typed)

Method	Returns
`CreateItemAsync<T>(T item, PartitionKey?, ItemRequestOptions?, CancellationToken)`	`ItemResponse<T>`
`ReadItemAsync<T>(string id, PartitionKey, ItemRequestOptions?, CancellationToken)`	`ItemResponse<T>`
`UpsertItemAsync<T>(T item, PartitionKey?, ItemRequestOptions?, CancellationToken)`	`ItemResponse<T>`
`ReplaceItemAsync<T>(T item, string id, PartitionKey?, ItemRequestOptions?, CancellationToken)`	`ItemResponse<T>`
`DeleteItemAsync<T>(string id, PartitionKey, ItemRequestOptions?, CancellationToken)`	`ItemResponse<T>`
`PatchItemAsync<T>(string id, PartitionKey, IReadOnlyList<PatchOperation>, PatchItemRequestOptions?, CancellationToken)`	`ItemResponse<T>`

CRUD Methods (Stream)

Method	Returns
`CreateItemStreamAsync(Stream, PartitionKey, ItemRequestOptions?, CancellationToken)`	`ResponseMessage`
`ReadItemStreamAsync(string id, PartitionKey, ItemRequestOptions?, CancellationToken)`	`ResponseMessage`
`UpsertItemStreamAsync(Stream, PartitionKey, ItemRequestOptions?, CancellationToken)`	`ResponseMessage`
`ReplaceItemStreamAsync(Stream, string id, PartitionKey, ItemRequestOptions?, CancellationToken)`	`ResponseMessage`
`DeleteItemStreamAsync(string id, PartitionKey, ItemRequestOptions?, CancellationToken)`	`ResponseMessage`
`PatchItemStreamAsync(string id, PartitionKey, IReadOnlyList<PatchOperation>, PatchItemRequestOptions?, CancellationToken)`	`ResponseMessage`

Query Methods

See SQL Queries for supported SQL syntax.

Method	Returns
`GetItemQueryIterator<T>(QueryDefinition, string?, QueryRequestOptions?)`	`FeedIterator<T>`
`GetItemQueryIterator<T>(string queryText, string?, QueryRequestOptions?)`	`FeedIterator<T>`
`GetItemQueryIterator<T>(FeedRange, QueryDefinition, string?, QueryRequestOptions?)`	`FeedIterator<T>`
`GetItemQueryStreamIterator(QueryDefinition, string?, QueryRequestOptions?)`	`FeedIterator`
`GetItemQueryStreamIterator(string queryText, string?, QueryRequestOptions?)`	`FeedIterator`
`GetItemQueryStreamIterator(FeedRange, QueryDefinition, string?, QueryRequestOptions?)`	`FeedIterator`
`GetItemLinqQueryable<T>(bool?, string?, QueryRequestOptions?, CosmosLinqSerializerOptions?)`	`IOrderedQueryable<T>`

Tip: For LINQ .ToFeedIterator() support in tests, see How Does ToFeedIterator() Work?.

ReadMany

Method	Returns
`ReadManyItemsAsync<T>(IReadOnlyList<(string, PartitionKey)>, ReadManyRequestOptions?, CancellationToken)`	`FeedResponse<T>`
`ReadManyItemsStreamAsync(IReadOnlyList<(string, PartitionKey)>, ReadManyRequestOptions?, CancellationToken)`	`ResponseMessage`

Change Feed

Method	Returns	Description
`GetChangeFeedIterator<T>(ChangeFeedStartFrom, ChangeFeedMode, ChangeFeedRequestOptions?)`	`FeedIterator<T>`	SDK-style iterator. Supports `Incremental` (latest version, deletes filtered) and `FullFidelity` modes
`GetChangeFeedIterator<T>(long checkpoint)`	`FeedIterator<T>`	Custom helper — all versions + delete tombstones from given checkpoint position
`GetChangeFeedStreamIterator(ChangeFeedStartFrom, ChangeFeedMode, ChangeFeedRequestOptions?)`	`FeedIterator`	Stream variant of SDK-style iterator
`GetChangeFeedProcessorBuilder<T>(string, ChangesHandler<T>)`	`ChangeFeedProcessorBuilder`	Legacy handler signature
`GetChangeFeedProcessorBuilder<T>(string, ChangeFeedHandler<T>)`	`ChangeFeedProcessorBuilder`	Context-aware handler signature
`GetChangeFeedProcessorBuilder(string, ChangeFeedStreamHandler)`	`ChangeFeedProcessorBuilder`	Stream handler signature
`GetChangeFeedProcessorBuilderWithManualCheckpoint<T>(string, ChangeFeedHandlerWithManualCheckpoint<T>)`	`ChangeFeedProcessorBuilder`	Manual checkpoint — advances only when `checkpointAsync` is called
`GetChangeFeedProcessorBuilderWithManualCheckpoint(string, ChangeFeedStreamHandlerWithManualCheckpoint)`	`ChangeFeedProcessorBuilder`	Stream manual checkpoint — advances only when `checkpointAsync` is called
`GetChangeFeedEstimator(string, Container)`	`ChangeFeedEstimator`	Returns a stubbed estimator
`GetChangeFeedEstimatorBuilder(string, ChangesEstimationHandler, TimeSpan?)`	`ChangeFeedProcessorBuilder`	Returns a no-op processor builder
`GetChangeFeedCheckpoint()`	`long`	Current position in change feed (advances on create, upsert, replace, patch, and delete)

Transactional Batch

Method	Returns
`CreateTransactionalBatch(PartitionKey)`	`TransactionalBatch`

Container Management

Method	Returns
`ReadContainerAsync(ContainerRequestOptions?, CancellationToken)`	`ContainerResponse`
`ReadContainerStreamAsync(ContainerRequestOptions?, CancellationToken)`	`ResponseMessage`
`ReplaceContainerAsync(ContainerProperties, ContainerRequestOptions?, CancellationToken)`	`ContainerResponse`
`ReplaceContainerStreamAsync(ContainerProperties, ContainerRequestOptions?, CancellationToken)`	`ResponseMessage`
`DeleteContainerAsync(ContainerRequestOptions?, CancellationToken)`	`ContainerResponse`
`DeleteContainerStreamAsync(ContainerRequestOptions?, CancellationToken)`	`ResponseMessage`
`DeleteAllItemsByPartitionKeyStreamAsync(PartitionKey, RequestOptions?, CancellationToken)`	`ResponseMessage`
`GetFeedRangesAsync(CancellationToken)`	`Task<IReadOnlyList<FeedRange>>`

Throughput (Stubbed)

Method	Returns
`ReadThroughputAsync(CancellationToken)`	`Task<int?>` (returns 400)
`ReadThroughputAsync(RequestOptions, CancellationToken)`	`ThroughputResponse`
`ReplaceThroughputAsync(int, RequestOptions?, CancellationToken)`	`ThroughputResponse`
`ReplaceThroughputAsync(ThroughputProperties, RequestOptions?, CancellationToken)`	`ThroughputResponse`

Test Infrastructure

Method	Returns	Description
`ClearItems()`	`void`	Remove all data
`ExportState()`	`string`	Export state as JSON
`ImportState(string json)`	`void`	Import state from JSON
`ExportStateToFile(string filePath)`	`void`	Export to file
`ImportStateFromFile(string filePath)`	`void`	Import from file
`RestoreToPointInTime(DateTimeOffset pointInTime)`	`void`	Restore container to state at given timestamp
`RegisterUdf(string name, Func<object[], object>)`	`void`	Register UDF for SQL
`RegisterStoredProcedure(string id, Func<PartitionKey, dynamic[], string>)`	`void`	Register sproc
`DeregisterStoredProcedure(string id)`	`void`	Remove sproc
`RegisterTrigger(string name, TriggerType, TriggerOperation, Func<JObject, JObject> preHandler)`	`void`	Register pre-trigger
`RegisterTrigger(string name, TriggerType, TriggerOperation, Action<JObject> postHandler)`	`void`	Register post-trigger
`DeregisterTrigger(string name)`	`void`	Remove trigger
`LoadPersistedState()`	`void`	Load state from `StateFilePath` if the file exists (no-op if missing). See State Persistence
`Dispose()`	`void`	If `StateFilePath` is set, exports state to that file before cleanup. Implements `IDisposable`

See Unit Testing for patterns using these methods.

`InMemoryCosmosClient`

In-memory implementation of CosmosClient. Manages databases and containers.

Namespace: CosmosDB.InMemoryEmulator
Inherits: Microsoft.Azure.Cosmos.CosmosClient
Sealed: No
Deprecated: Yes ([Obsolete] in 4.0 — use InMemoryCosmos.Create() or InMemoryCosmos.Builder() instead)

Properties

Property	Type	Description
`Endpoint`	`Uri`	Always `https://localhost:8081/`
`ClientOptions`	`CosmosClientOptions`	Default options
`ResponseFactory`	`CosmosResponseFactory`	Stubbed response factory

Methods

Method	Returns	Description
`GetDatabase(string id)`	`Database`	Get or create database (lazy)
`GetContainer(string dbId, string containerId)`	`Container`	Get or create container (lazy)
`CreateDatabaseAsync(string id, int?, ...)`	`DatabaseResponse`	Create database (409 if exists)
`CreateDatabaseAsync(string id, ThroughputProperties?, ...)`	`DatabaseResponse`	Create with throughput properties
`CreateDatabaseIfNotExistsAsync(string id, int?, ...)`	`DatabaseResponse`	Create or get database
`CreateDatabaseIfNotExistsAsync(string id, ThroughputProperties?, ...)`	`DatabaseResponse`	Create or get with throughput properties
`CreateDatabaseStreamAsync(DatabaseProperties, int?, ...)`	`ResponseMessage`	Stream variant
`GetDatabaseQueryIterator<T>(string?, string?, QueryRequestOptions?)`	`FeedIterator<T>`	List all databases
`GetDatabaseQueryIterator<T>(QueryDefinition?, string?, QueryRequestOptions?)`	`FeedIterator<T>`	List databases by query
`GetDatabaseQueryStreamIterator(string?, string?, QueryRequestOptions?)`	`FeedIterator`	Stream variant
`GetDatabaseQueryStreamIterator(QueryDefinition?, string?, QueryRequestOptions?)`	`FeedIterator`	Stream variant
`ReadAccountAsync()`	`AccountProperties`	Returns synthetic account info

`InMemoryDatabase`

In-memory implementation of Database.

Namespace: CosmosDB.InMemoryEmulator
Inherits: Microsoft.Azure.Cosmos.Database
Sealed: Yes

Constructors

InMemoryDatabase(string id)
InMemoryDatabase(string id, InMemoryCosmosClient client)

Properties

Property	Type	Description
`Id`	`string`	Database identifier
`Client`	`CosmosClient`	Parent client (stubbed if not provided)

Container Methods

Method	Returns	Description
`GetContainer(string id)`	`Container`	Get or create container (lazy)
`CreateContainerAsync(string id, string pkPath, ...)`	`ContainerResponse`	Create (409 if exists)
`CreateContainerAsync(ContainerProperties, int?, ...)`	`ContainerResponse`	Create with properties
`CreateContainerAsync(ContainerProperties, ThroughputProperties?, ...)`	`ContainerResponse`	Create with throughput
`CreateContainerIfNotExistsAsync(string id, string pkPath, ...)`	`ContainerResponse`	Create or get
`CreateContainerIfNotExistsAsync(ContainerProperties, int?, ...)`	`ContainerResponse`	Create or get with properties
`CreateContainerIfNotExistsAsync(ContainerProperties, ThroughputProperties?, ...)`	`ContainerResponse`	Create or get with throughput
`CreateContainerStreamAsync(ContainerProperties, int?, ...)`	`ResponseMessage`	Stream variant
`CreateContainerStreamAsync(ContainerProperties, ThroughputProperties?, ...)`	`ResponseMessage`	Stream variant with throughput
`GetContainerQueryIterator<T>(string?, string?, QueryRequestOptions?)`	`FeedIterator<T>`	List containers
`GetContainerQueryIterator<T>(QueryDefinition?, string?, QueryRequestOptions?)`	`FeedIterator<T>`	List containers by query
`GetContainerQueryStreamIterator(string?, string?, QueryRequestOptions?)`	`FeedIterator`	Stream variant
`GetContainerQueryStreamIterator(QueryDefinition?, string?, QueryRequestOptions?)`	`FeedIterator`	Stream variant
`DefineContainer(string name, string pkPath)`	`ContainerBuilder`	Fluent container builder

Database Methods

Method	Returns	Description
`ReadAsync(...)`	`DatabaseResponse`	Read database properties
`ReadStreamAsync(...)`	`ResponseMessage`	Stream variant
`DeleteAsync(...)`	`DatabaseResponse`	Delete database and all containers
`DeleteStreamAsync(...)`	`ResponseMessage`	Stream variant

Throughput (Stubbed)

Method	Returns
`ReadThroughputAsync(CancellationToken)`	`Task<int?>`
`ReadThroughputAsync(RequestOptions, CancellationToken)`	`ThroughputResponse`
`ReplaceThroughputAsync(int, RequestOptions?, CancellationToken)`	`ThroughputResponse`
`ReplaceThroughputAsync(ThroughputProperties, RequestOptions?, CancellationToken)`	`ThroughputResponse`

User Management

Method	Returns	Description
`GetUser(string id)`	`User`	Get or create user (lazy)
`CreateUserAsync(string id, ...)`	`UserResponse`	Create user (409 if exists)
`UpsertUserAsync(string id, ...)`	`UserResponse`	Create or replace user
`GetUserQueryIterator<T>(string?, string?, QueryRequestOptions?)`	`Task<FeedIterator<T>>`	List users
`GetUserQueryIterator<T>(QueryDefinition?, string?, QueryRequestOptions?)`	`Task<FeedIterator<T>>`	List users by query

`InMemoryUser`

In-memory implementation of User.

Namespace: CosmosDB.InMemoryEmulator
Inherits: Microsoft.Azure.Cosmos.User
Sealed: Yes

Properties

Property	Type	Description
`Id`	`string`	User identifier

Methods

Method	Returns	Description
`ReadAsync(...)`	`UserResponse`	Read user properties
`ReplaceAsync(UserProperties, ...)`	`UserResponse`	Replace user properties
`DeleteAsync(...)`	`UserResponse`	Delete user
`GetPermission(string id)`	`Permission`	Get permission by id
`CreatePermissionAsync(PermissionProperties, int?, ...)`	`PermissionResponse`	Create permission (409 if exists)
`UpsertPermissionAsync(PermissionProperties, int?, ...)`	`PermissionResponse`	Create or replace permission
`GetPermissionQueryIterator<T>(string?, string?, QueryRequestOptions?)`	`FeedIterator<T>`	List permissions
`GetPermissionQueryIterator<T>(QueryDefinition?, string?, QueryRequestOptions?)`	`FeedIterator<T>`	List permissions by query

`InMemoryPermission`

In-memory implementation of Permission.

Namespace: CosmosDB.InMemoryEmulator
Inherits: Microsoft.Azure.Cosmos.Permission
Sealed: Yes

Properties

Property	Type	Description
`Id`	`string`	Permission identifier

Methods

Method	Returns	Description
`ReadAsync(int?, ...)`	`PermissionResponse`	Read permission properties
`ReplaceAsync(PermissionProperties, int?, ...)`	`PermissionResponse`	Replace permission properties
`DeleteAsync(...)`	`PermissionResponse`	Delete permission

`FakeCosmosHandler`

HTTP message handler that intercepts Cosmos SDK requests and serves them from an InMemoryContainer. Used internally by all integration approaches — see the Setup Guide for usage examples.

Namespace: CosmosDB.InMemoryEmulator
Inherits: System.Net.Http.HttpMessageHandler

Constructors

FakeCosmosHandler(InMemoryContainer container)
FakeCosmosHandler(InMemoryContainer container, FakeCosmosHandlerOptions options)

Properties

Property	Type	Description
`BackingContainer`	`InMemoryContainer`	The underlying in-memory container
`RequestLog`	`IReadOnlyCollection<string>`	Recorded HTTP requests
`QueryLog`	`IReadOnlyCollection<string>`	Recorded SQL queries
`FaultInjector`	`Func<HttpRequestMessage, HttpResponseMessage?>?`	Fault injection delegate
`FaultInjectorIncludesMetadata`	`bool`	Whether faults affect metadata routes

Static Methods

Method	Returns	Description
~~`CreateRouter()`~~	—	Removed in 3.0.0 — use `InMemoryCosmos.Builder()`
~~`CreateClient()`~~	—	Removed in 3.0.0 — use `InMemoryCosmos.Builder()`
~~`WrapClient()`~~	—	Removed in 3.0.0 — use `InMemoryCosmos.Builder()`
`VerifySdkCompatibilityAsync()`	`Task`	SDK compatibility self-test

Instance Methods

Method	Returns	Description
~~`CreateClient()`~~	—	Removed in 3.0.0 — use `InMemoryCosmos.Create()`
~~`WrapClient(CosmosClient)`~~	—	Removed in 3.0.0 — use `InMemoryCosmos.Create()`

`FakeCosmosHandlerOptions`

Configuration for FakeCosmosHandler.

Namespace: CosmosDB.InMemoryEmulator
Sealed: Yes

Property	Type	Default	Description
`CacheTtl`	`TimeSpan`	5 min	Query result cache TTL
`CacheMaxEntries`	`int`	100	Max cached query results
`PartitionKeyRangeCount`	`int`	1	Number of simulated partition ranges

`InMemoryFeedIterator<T>`

In-memory implementation of FeedIterator<T>.

Namespace: CosmosDB.InMemoryEmulator
Inherits: Microsoft.Azure.Cosmos.FeedIterator<T>

Constructors

InMemoryFeedIterator(IReadOnlyList<T> items, int? maxItemCount = null, int initialOffset = 0)
InMemoryFeedIterator(IEnumerable<T> source, int? maxItemCount = null)
InMemoryFeedIterator(Func<IReadOnlyList<T>> factory, int? maxItemCount = null)

`InMemoryTransactionalBatch`

In-memory implementation of TransactionalBatch. Supports CreateItem, UpsertItem, ReplaceItem, DeleteItem, ReadItem, PatchItem, and their stream variants. All operations execute atomically via ExecuteAsync.

Namespace: CosmosDB.InMemoryEmulator
Inherits: Microsoft.Azure.Cosmos.TransactionalBatch

Constructor

InMemoryTransactionalBatch(InMemoryContainer container, PartitionKey partitionKey)

`InMemoryFeedIteratorSetup`

Wires up ToFeedIteratorOverridable() to return InMemoryFeedIterator<T>. See How Does ToFeedIterator() Work? for details.

Namespace: CosmosDB.InMemoryEmulator

Method	Description
`Register()`	Enable in-memory feed iterator interception
`Deregister()`	Disable interception, revert to SDK behaviour

`IJsTriggerEngine`

Interface for executing JavaScript trigger bodies. Implemented by JintTriggerEngine in the JsTriggers package, or provide a custom implementation.

Namespace: CosmosDB.InMemoryEmulator

Method	Returns	Description
`ExecutePreTrigger(string jsBody, JObject document)`	`JObject`	Execute pre-trigger, returns (possibly modified) document
`ExecutePreTrigger(string jsBody, JObject document, ICollectionContext context)`	`JObject`	Execute pre-trigger with collection CRUD access
`ExecutePostTrigger(string jsBody, JObject document)`	`JObject?`	Execute post-trigger
`ExecutePostTrigger(string jsBody, JObject document, ICollectionContext context)`	`JObject?`	Execute post-trigger with collection CRUD access

`IJsUdfEngine`

Interface for executing JavaScript UDF bodies. Implemented by JintTriggerEngine.

Namespace: CosmosDB.InMemoryEmulator

Method	Returns	Description
`ExecuteUdf(string jsBody, object[] args)`	`object?`	Execute a JavaScript UDF function body

`ICollectionContext`

Partition-scoped document CRUD operations for use inside JavaScript stored procedures and triggers.

Namespace: CosmosDB.InMemoryEmulator

Member	Returns	Description
`CreateDocument(JObject document)`	`JObject`	Insert a document
`ReadDocument(string id)`	`JObject`	Read a document by ID
`QueryDocuments(string sql)`	`IReadOnlyList<JObject>`	Execute SQL query within partition
`ReplaceDocument(string id, JObject document)`	`JObject`	Replace a document
`DeleteDocument(string id)`	`void`	Delete a document by ID
`SelfLink`	`string`	Collection self link

`ServiceCollectionExtensions`

DI extension methods for IServiceCollection. See the Setup Guide for usage examples.

Namespace: CosmosDB.InMemoryEmulator

Method	Description
`UseInMemoryCosmosDB(Action<InMemoryCosmosOptions>?)`	Replace `CosmosClient` + `Container` registrations using `FakeCosmosHandler`
`UseInMemoryCosmosContainers(Action<InMemoryContainerOptions>?)`	Replace `Container` registrations only
`UseInMemoryCosmosDB<TClient>(Action<InMemoryCosmosOptions>?)`	Replace typed `CosmosClient` subclass + `Container` registrations

`InMemoryCosmosOptions`

Options for UseInMemoryCosmosDB() and UseInMemoryCosmosDB<TClient>().

Namespace: CosmosDB.InMemoryEmulator

Property	Type	Default	Description
`Containers`	`List<ContainerConfig>`	Empty	Container configurations
`DatabaseName`	`string?`	`"in-memory-db"`	Default database name
`RegisterFeedIteratorSetup`	`bool`	`true`	Ignored — all DI methods now use `FakeCosmosHandler` which handles `.ToFeedIterator()` natively
`OnClientCreated`	`Action<CosmosClient>?`	null	Post-creation callback (receives real `CosmosClient` backed by `FakeCosmosHandler`, or a Castle.Core dynamic proxy for the `<TClient>` overload)
`OnHandlerCreated`	`Action<string, FakeCosmosHandler>?`	null	Per-container handler callback. Fires for all DI methods including `UseInMemoryCosmosDB<TClient>()`
`HttpMessageHandlerWrapper`	`Func<HttpMessageHandler, HttpMessageHandler>?`	null	Wraps the `FakeCosmosHandler`/router before it's passed to `HttpClientFactory`. Applies to all DI methods including `UseInMemoryCosmosDB<TClient>()`
`StatePersistenceDirectory`	`string?`	null	Directory for automatic state persistence. Container state is loaded on creation and saved on disposal. Files are named `{DatabaseName}_{ContainerName}.json`. See State Persistence
Method	Returns	Description
--------	---------	-------------
`AddContainer(string containerName, string partitionKeyPath = "/id", string? databaseName = null)`	`InMemoryCosmosOptions`	Fluent helper to add a container configuration
`WithHttpMessageHandlerWrapper(Func<HttpMessageHandler, HttpMessageHandler> wrapper)`	`InMemoryCosmosOptions`	Fluent helper to set `HttpMessageHandlerWrapper`

`InMemoryContainerOptions`

Options for UseInMemoryCosmosContainers().

Namespace: CosmosDB.InMemoryEmulator

Property	Type	Default	Description
`Containers`	`List<ContainerConfig>`	Empty	Container configurations
~~`RegisterFeedIteratorSetup`~~	`bool`	`true`	Obsolete. Ignored — `FakeCosmosHandler` handles `.ToFeedIterator()` natively
`OnContainerCreated`	`Action<InMemoryContainer>?`	null	Per-container callback
`StatePersistenceDirectory`	`string?`	null	Directory for automatic state persistence. Container state is loaded on creation and saved on disposal. Files are named `{ContainerName}.json`. See State Persistence

Method	Returns	Description
`AddContainer(string containerName = "in-memory-container", string partitionKeyPath = "/id")`	`InMemoryContainerOptions`	Fluent helper to add a container configuration

`ContainerConfig`

public record ContainerConfig(
    string ContainerName,
    string PartitionKeyPath = "/id",
    string? DatabaseName = null);

`CosmosSqlParser`

Cosmos DB SQL parser (internal details exposed for advanced use).

Namespace: CosmosDB.InMemoryEmulator

Method	Returns	Description
`Parse(string sql)`	`CosmosSqlQuery`	Parse SQL (throws on failure)
`TryParse(string sql, out CosmosSqlQuery)`	`bool`	Parse SQL (returns false on failure)

Package: CosmosDB.InMemoryEmulator.ProductionExtensions

`CosmosOverridableFeedIteratorExtensions`

Drop-in replacement for .ToFeedIterator() that can be intercepted in tests. See How Does ToFeedIterator() Work? for full usage.

Namespace: CosmosDB.InMemoryEmulator.ProductionExtensions

Member	Type	Description
`ToFeedIteratorOverridable<T>(this IQueryable<T>)`	Extension method	Drop-in replacement for `.ToFeedIterator()`
`FeedIteratorFactory`	`Func<object, object>?`	Per-async-flow factory (AsyncLocal)
`StaticFallbackFactory`	`Func<object, object>?`	Global fallback for `new Thread()` scenarios

The extension method checks factories in this order:

FeedIteratorFactory (AsyncLocal, per-async-flow)
StaticFallbackFactory (static, global fallback)
.ToFeedIterator() (real Cosmos SDK — production path)

Package: CosmosDB.InMemoryEmulator.JsTriggers

Optional package that provides a Jint-based JavaScript engine for executing real Cosmos DB trigger scripts in tests.

`JintTriggerEngine`

JavaScript trigger engine built on Jint.

Namespace: CosmosDB.InMemoryEmulator.JsTriggers
Implements: IJsTriggerEngine, IJsUdfEngine

Method	Returns	Description
`ExecutePreTrigger(string jsBody, JObject document)`	`JObject`	Execute pre-trigger JavaScript, returns modified document
`ExecutePreTrigger(string jsBody, JObject document, ICollectionContext context)`	`JObject`	Execute pre-trigger with collection CRUD access
`ExecutePostTrigger(string jsBody, JObject document)`	`JObject?`	Execute post-trigger JavaScript
`ExecutePostTrigger(string jsBody, JObject document, ICollectionContext context)`	`JObject?`	Execute post-trigger with collection CRUD access
`ExecuteUdf(string jsBody, object[] args)`	`object?`	Execute JavaScript UDF body

`JintSprocEngine`

JavaScript stored procedure engine built on Jint.

Namespace: CosmosDB.InMemoryEmulator.JsTriggers
Implements: ISprocEngine

Method	Returns	Description
`Execute(string jsBody, PartitionKey pk, dynamic[] args)`	`string?`	Execute stored procedure without collection access
`Execute(string jsBody, PartitionKey pk, dynamic[] args, ICollectionContext ctx)`	`string?`	Execute stored procedure with partition-scoped collection CRUD
`CapturedLogs`	`IReadOnlyList<string>`	Console.log output from last execution

`JsTriggerExtensions`

Extension method to wire up the Jint engine.

Namespace: CosmosDB.InMemoryEmulator.JsTriggers

Method	Returns	Description
`UseJsTriggers(this InMemoryContainer)`	`InMemoryContainer`	Sets `JsTriggerEngine` to a `JintTriggerEngine` instance

Home

Getting Started

Integration & Dependency Injection

Data Management

Reference

Help

API Reference

Package: CosmosDB.InMemoryEmulator

InMemoryCosmos (Static)

InMemoryCosmosBuilder

InMemoryCosmosResult : IDisposable, IAsyncDisposable

InMemoryDatabaseResult

IContainerTestSetup

InMemoryContainer

Constructors

Properties

CRUD Methods (Typed)

CRUD Methods (Stream)

Query Methods

ReadMany

Change Feed

Transactional Batch

Container Management

Throughput (Stubbed)

Test Infrastructure

InMemoryCosmosClient

Properties

Methods

InMemoryDatabase

Constructors

Properties

Container Methods

Database Methods

Throughput (Stubbed)

User Management

InMemoryUser

Properties

Methods

InMemoryPermission

Properties

Methods

FakeCosmosHandler

Constructors

Properties

Static Methods

Instance Methods

FakeCosmosHandlerOptions

InMemoryFeedIterator<T>

Constructors

InMemoryTransactionalBatch

Constructor

InMemoryFeedIteratorSetup

IJsTriggerEngine

IJsUdfEngine

ICollectionContext

ServiceCollectionExtensions

InMemoryCosmosOptions

InMemoryContainerOptions

ContainerConfig

CosmosSqlParser

Package: CosmosDB.InMemoryEmulator.ProductionExtensions

CosmosOverridableFeedIteratorExtensions

Package: CosmosDB.InMemoryEmulator.JsTriggers

JintTriggerEngine

JintSprocEngine

JsTriggerExtensions

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

`InMemoryCosmos` (Static)

`InMemoryCosmosBuilder`

`InMemoryCosmosResult` : `IDisposable`, `IAsyncDisposable`

`InMemoryDatabaseResult`

`IContainerTestSetup`

`InMemoryContainer`

`InMemoryCosmosClient`

`InMemoryDatabase`

`InMemoryUser`

`InMemoryPermission`

`FakeCosmosHandler`

`FakeCosmosHandlerOptions`

`InMemoryFeedIterator<T>`

`InMemoryTransactionalBatch`

`InMemoryFeedIteratorSetup`

`IJsTriggerEngine`

`IJsUdfEngine`

`ICollectionContext`

`ServiceCollectionExtensions`

`InMemoryCosmosOptions`

`InMemoryContainerOptions`

`ContainerConfig`

`CosmosSqlParser`

`CosmosOverridableFeedIteratorExtensions`

`JintTriggerEngine`

`JintSprocEngine`

`JsTriggerExtensions`