new-java-e2e-test-yaml-and-test

Creating a New Java E2E Test with a Replay Proxy YAML Snapshot

This skill covers the complete workflow for adding a new Java failsafe integration test backed by a handcrafted YAML snapshot for the replay proxy.

Overview

The Java E2E tests use a replay proxy (test/harness/replayingCapiProxy.ts) that intercepts HTTP calls to the Copilot API and returns pre-recorded responses from YAML snapshot files. This avoids needing real authentication in CI.

Key constraint: Java's CapiProxy.java always sets GITHUB_ACTIONS=true (line 104), which forces the replay proxy into read-only mode. You cannot record snapshots by running Java tests — you must handcraft the YAML.

Step-by-Step Workflow

Step 1: Choose a snapshot category and snapshot base name

• Category = a directory under test/snapshots/ (e.g., system_message_sections)
• Snapshot base name = the exact filename stem to use (already lowercase/underscore-separated), e.g., should_use_replaced_identity_section_in_response
• Resulting file: test/snapshots/<category>/<snapshot_base_name>.yaml

Step 2: Create the YAML snapshot file

The format is:

models:
  - claude-sonnet-4.5
conversations:
  - messages:
      - role: system
        content: ${system}
      - role: user
        content: <the exact prompt your test will send>
      - role: assistant
        content: <the response the proxy will return>

Rules:

• ${system} is a placeholder that matches ANY system message content
• ${workdir} in tool arguments is substituted with the actual temp workDir
• Each conversation entry represents one request-response exchange
• For multi-turn, add multiple conversation entries
• For tool calls, include tool_calls on assistant messages and role: tool for results
• The user content must exactly match what your test sends (after normalization)

Step 3: Create the Java IT test class

Place it in java/sdk/src/test/java/com/github/copilot/ with an IT suffix (e.g., MyFeatureIT.java). The failsafe plugin picks up *IT.java files.