ripr: Rust Test-Oracle Gaps

Preview VS Code/Open VSX extension for ripr, a static Rust analysis tool that finds weak or missing test oracles and guides the next targeted test.

The extension starts ripr lsp --stdio, surfaces saved-workspace diagnostics, and helps a human or coding agent move from static evidence to one focused test.

Requirements

The extension can download and cache the matching ripr server binary from GitHub Releases on first activation. Manual installation is still supported for offline, pinned, or enterprise-controlled environments.

Install and First Run

Install EffortlessMetrics.ripr from VS Code Marketplace or Open VSX. The extension should resolve its server automatically, so cargo install ripr is a fallback rather than a required first step.

After opening a Rust/Cargo workspace:

1. Check the ripr status bar item for server, workspace, analysis, first-useful-action, stale, failed, or no-actionable-seam state. The status bar projects an existing workspace-matched target/ripr/reports/first-useful-action.json report when one is present, without rerunning analysis.
2. Use the Problems panel to find actionable saved-workspace seam diagnostics.
3. Hover a diagnostic to see why RIPR flagged it. The seam hover names the missing discriminator, related test, suggested test shape, verify and receipt commands, and projects an existing first-useful-action match for the same seam.
4. Use the intent-titled code actions to copy the targeted test brief, the suggested assertion, or the agent handoff command chain.
5. Open the best related test when RIPR finds an imitation target.
6. Add one focused test.
7. Verify with the copied command chain or the CI artifact packet.

Unsaved-buffer overlays are not enabled by default.

For the full editor loop from diagnostic to receipt, see docs/EDITOR_EVIDENCE_WORKFLOW.md.

What ripr Does

ripr scans Rust code for mutation-shaped static seams and reports whether tests appear to contain the discriminators needed to expose the changed behavior. It uses conservative static-exposure language and is meant to guide the next useful test, not to prove test adequacy.

The 0.5.x extension surfaces saved-workspace seam diagnostics, evidence-aware hovers, intent-titled code actions for inspecting the seam / writing the targeted test / copying the agent handoff / verifying after the test / reviewing the receipt / refreshing analysis, an LSP collectEvidenceContext seam handoff packet, and a first-useful-action projection in the status bar and seam hover when a workspace-matched report already exists.

It does not run mutation testing, report killed/survived, or prove test adequacy. Use real mutation testing, such as cargo-mutants, for ready-mode confirmation.

Settings

• ripr.server.path: explicit path to the ripr executable. Empty by default.
• ripr.enabled: enables saved-workspace diagnostics, hovers, status, and code actions. Defaults to true.
• ripr.server.args: arguments used to start the language server. Defaults to ["lsp", "--stdio"].
• ripr.server.autoDownload: download a matching server when needed. Defaults to true.
• ripr.server.version: pinned server version. Empty means match the extension version.
• ripr.server.downloadBaseUrl: override the manifest location for internal mirrors.
• ripr.check.mode: preferred editor check mode. Defaults to draft.
• ripr.baseRef: Git base ref used by context commands. Defaults to origin/main.
• ripr.trace.server: language-server trace setting.

Commands

• ripr: Restart Server
• ripr: Show Status
• ripr: Show Output
• ripr: Copy Finding Context
• ripr: Write Targeted Test - Copy Suggested Assertion
• ripr: Write Targeted Test - Copy Brief
• ripr: Agent Handoff - Copy Packet Command
• ripr: Agent Handoff - Copy Brief Command
• ripr: Verify After Test - Copy After Snapshot Command
• ripr: Verify After Test - Copy Verify Command
• ripr: Review Result - Copy Receipt Command
• ripr: Write Targeted Test - Open Best Related Test
• ripr: Open Settings

Preview Limitations

The 0.5.x extension uses a universal VSIX and downloads native server binaries from matching GitHub Releases when available. It does not auto-install Rust tooling, run mutation tests, make automatic edits, or analyze unsaved buffer overlays by default. Bundled platform-specific VSIXs are planned after the downloader path is proven.