Using standard tests ↗

langchain guide intermediate testing workflows
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Original Documentation

Documentation Index#

Fetch the complete documentation index at: https://docs.langchain.com/llms.txt Use this file to discover all available pages before exploring further.

Standard tests ensure your integration works as expected.

When creating either a custom class for yourself or to publish in a LangChain integration, it is necessary to add tests to ensure it works as expected. LangChain provides a comprehensive set of tests for each integration type for you. This guide will show you how to add LangChain’s standard test suite to each integration type.

Setup#

First, install the required dependencies:

Defines the interfaces we want to import to define our custom components

Provides the standard tests and plugins necessary to run them 

npm install @langchain/core
npm install @langchain/standard-tests
pnpm add @langchain/core
pnpm add @langchain/standard-tests
yarn add @langchain/core
yarn add @langchain/standard-tests
bun add @langchain/core
bun add @langchain/standard-tests

There are 2 namespaces in the langchain-tests package:

**Location**: `src.unit_tests`

Designed to test the component in isolation and without access to external services

View API reference

**Location**: `src.integration_tests`

Designed to test the component with access to external services (in particular, the external service that the component is designed to interact with)

View API reference

Implementing standard tests#

Depending on your integration type, you will need to implement either or both unit and integration tests.

By subclassing the standard test suite for your integration type, you get the full collection of standard tests for that type. For a test run to be successful, the a given test should pass only if the model supports the capability being tested. Otherwise, the test should be skipped.

Because different integrations offer unique sets of features, most standard tests provided by LangChain are opt-in by default to prevent false positives. Consequently, you will need to override properties to indicate which features your integration supports - see the below example for an illustration.

// Indicate that a chat model supports parallel tool calls

class ChatParrotLinkStandardIntegrationTests extends ChatModelIntegrationTests<
    ChatParrotLinkCallOptions,
    AIMessageChunk
> {
    constructor() {
        // ... other required properties

        super({
            // ... other required properties
            supportsParallelToolCalls: true,  // (The default is False)
            // ...
        });
    }

You should organize tests in these subdirectories relative to the root of your package:

  • tests/unit_tests for unit tests
  • tests/integration_tests for integration tests

To see the complete list of configurable capabilities and their defaults, visit the API reference for standard tests.

Sandbox integrations#

Deep agents sandbox integrations use sandboxStandardTests from @langchain/sandbox-standard-tests. Call it with a config object that includes createSandbox, resolvePath, and closeSandbox. Use the Daytona integration tests as a reference implementation. See Contributing a sandbox integration for publishing guidelines.

Troubleshooting#

For a full list of the standard test suites that are available, as well as information on which tests are included and how to troubleshoot common issues, see the Standard Tests API Reference.

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Link last verified June 7, 2026. View original ↗
Source: LangChain Docs
Link last verified: 2026-03-04