Using standard tests

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:

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:

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, 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)
            // ...
        });
    }

To see the complete list of configurable capabilities and their defaults, see Implementing 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 contributing README.