Handle empty session fork behavior in E2E tests

[stephentoub]

Runtime behavior changed so forking a newly-created session with no persisted conversation can either fail with the older "no persisted events" error or return a successful empty fork. The SDK E2E tests should accept both behaviors while still confirming that sessions.fork is implemented and produces a sensible fork when it succeeds.

Changes

• Updates the empty-session fork E2E test in C#, Node, Python, and Go to accept either the old error or a successful empty fork.
• Verifies successful empty forks have a non-empty, distinct session ID and no conversation messages.
• Marks the C# test project explicitly with IsTestProject=true so dotnet test discovers and runs the xUnit tests with the installed SDK.

Validation

• Normal SDK CLI resolution: targeted C#, Node, Python, and Go empty-session fork tests passed.
• COPILOT_CLI_PATH=D:\repos\copilot-agent-runtime\dist-cli\index.js: targeted C#, Node, Python, and Go empty-session fork tests passed.

[Copilot]

Pull request overview

Updates multi-language E2E coverage to tolerate the runtime’s new “empty session fork” behavior (either the historical error or a successful empty fork), while still validating that sessions.fork is implemented and produces a sensible result when it succeeds.

Changes:

• Adjusts empty-session fork E2E tests (Python/Node/Go/.NET) to accept either an expected “no persisted events” failure or a successful empty fork.
• Adds assertions for the success case: fork session ID is non-empty/distinct, and the forked session has no conversation messages.
• Marks the .NET test project as a test project (IsTestProject=true) to improve dotnet test discovery.

Show a summary per file

File	Description
python/e2e/test_rpc_session_state_e2e.py	Accepts either error or successful empty fork; validates empty conversation on success.
nodejs/test/e2e/rpc_session_state.e2e.test.ts	Accepts either error or successful empty fork; resumes fork to validate empty conversation on success.
go/internal/e2e/rpc_session_state_e2e_test.go	Accepts either error or successful empty fork; validates non-empty new session ID and empty conversation on success.
dotnet/test/GitHub.Copilot.SDK.Test.csproj	Sets IsTestProject=true for improved xUnit discovery via dotnet test.
dotnet/test/E2E/RpcSessionStateE2ETests.cs	Accepts either error or successful empty fork; validates new session ID and empty conversation on success.

Copilot's findings

• Files reviewed: 5/5 changed files
• Comments generated: 0

[github-actions]

Cross-SDK Consistency Review ✅

This PR updates the empty-session fork E2E test across all four SDK implementations (Node.js, Python, Go, .NET) with consistent behavior.

All four SDKs equivalently:

• Rename the test to reflect the dual-outcome expectation
• Accept both the legacy error response and a successful empty fork
• On error: assert the message contains "not found or has no persisted events" and does not contain "unhandled method sessions.fork"
• On success: assert the fork has a non-empty, distinct session ID and zero conversation messages
• Properly disconnect sessions on all code paths (including the Go test, which now correctly adds defer session.Disconnect())

No cross-language inconsistencies were found. Language-idiomatic differences (Go's defer, .NET's Record.ExceptionAsync, Python's try/except) are appropriate and don't affect the semantic behavior being tested.

Generated by SDK Consistency Review Agent for issue #1247 · ● 153.5K · ◷

[stomde]

Gees