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LangChain

As explained in Software Testing with Generative AI

LangChain is a software library and toolset for developing applications that integrate with language models.

LangChain is a library and toolset for connecting language models to application workflows. A Java RAG example uses LangChain4j to retrieve a relevant user story, add it to a prompt, and send the result to OpenAI. section 11.2.1

A practical LangChain workflow can:

  • Load user stories or other documents into a corpus. section 11.2.1
  • Accept a testing question from the command line. section 11.2.1
  • Select a document with cosine-distance matching and include it in a structured prompt. section 11.2.1
  • Return model-generated testing risks for human review. section 11.2.1

Testing-risk assistant

Given the query “I want a list of risks to test for the delete booking endpoint,” the workflow retrieves a user story, combines it with the query, and asks GPT for suggested risks. Cosine-distance retrieval can select an unrelated story, so the result requires verification. section 11.2.1

<dependencies>
 
    <dependency>                                     #1
        <groupId>commons-io</groupId>                #1
        <artifactId>commons-io</artifactId>          #1
        <version>2.16.1</version>                    #1
    </dependency>
 
    <dependency>                                     #2
        <groupId>org.apache.commons</groupId>        #2
        <artifactId>commons-text</artifactId>        #2
        <version>1.12.0</version>                    #2
    </dependency>                                    #2
 
<dependency>                                         #3
    <groupId>dev.langchain4j</groupId>               #3
    <artifactId>langchain4j-open-ai</artifactId>     #3
    <version>0.31.0</version>                        #3
</dependency>                                        #3

Shows the Maven dependency for LangChain4j’s OpenAI integration alongside supporting document-processing libraries. section 11.2.1

How Software Testing with Generative AI covers it

How deep it goes
Demonstrates document loading, query input, cosine-distance retrieval, prompt construction, and model invocation, while noting retrieval limitations.
Examples
Uses a Java command-line assistant that retrieves booking user stories and recommends testing risks.
What it assumes
Assumes basic Java development and requires an OpenAI Project API key configured directly or through an environment variable.
What you can do after
Build it from scratch as a Java RAG workflow that loads documents, retrieves context, and sends prompts to OpenAI.
How it connects
Connects retrieval-augmented generation with prompts, cosine distance, user stories, and the OpenAI API.

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This explainer was generated by Manning's knowledge graph from the text of Software Testing with Generative AI. The section links point to the parts of the book it draws on.