VS Code Extensions
CoverLens

CoverLens

by fogio

CoverLens is a VS Code extension that visualizes covered, partially covered, and uncovered code lines while integrating test runners, coverage files, diff mode, deltas, and monorepo support.

Downloads

214

Rating

5.0 / 5 (2)

Version

1.1.0

Last updated

Jun 05, 2026

Three-state code coverage visualization for VS Code — see covered, partially covered, and uncovered lines at a glance.

VS Code Marketplace:

VS Code Marketplace Version  VS Code Marketplace Rating  VS Code Marketplace Downloads  VS Code Marketplace Installs

Open VSX:

Open VSX Version  Open VSX Rating  Open VSX Downloads  Open VSX Release Date

Features

  • Three coverage states — covered (green), partial branches (yellow), uncovered (red)
  • Two display modes — minimal left border or border + background highlight
  • No gutter conflicts — uses line decorations instead of gutter icons, so coverage display never interferes with debugger breakpoints
  • Diff mode — show coverage only on lines changed vs a base branch
  • Built-in test runner — run tests with coverage in one click; scoped runs for changed packages
  • Smart auto-run — on save, runs tests only for the affected package (Go, Jest, Vitest, pytest, Dart, Flutter)
  • Coverage delta — shows coverage change vs session start or vs base branch in diff mode
  • Stale coverage — dims or hides decorations while tests run or after edits
  • Monorepo support — auto-detects pnpm/npm/yarn workspaces, aggregates coverage
  • Explorer panel — tree view with per-file coverage percentages and threshold icons
  • Status bar — project-wide coverage %, spinner during test runs, click to run full tests
  • Auto-reload — watches coverage files and updates decorations on change

Supported Languages & Formats

Language Test Runner Coverage Format
JavaScript / TypeScript Jest, Vitest LCOV, Istanbul JSON
Python pytest LCOV, Cobertura XML
Go go test Go coverage profile
Rust cargo-tarpaulin LCOV
C# / .NET dotnet test + Coverlet LCOV, Cobertura XML
Dart dart test LCOV
Flutter flutter test LCOV
Java / Kotlin Gradle, Maven JaCoCo XML

Auto-detects format by file content — works with any tool that outputs a supported format.

Getting Started

  1. Install CoverLens from the Marketplace
  2. Generate coverage with your test runner:
# JavaScript (Jest)
npx jest --coverage

# TypeScript (Vitest)
npx vitest run --coverage

# Python
python -m pytest --cov=. --cov-report=lcov:lcov.info

# Go
go test ./... -coverprofile=coverage.out

# Rust
cargo tarpaulin --out Lcov

# .NET
dotnet test /p:CollectCoverage=true /p:CoverletOutputFormat=lcov

# Dart (requires the `coverage` dev_dependency)
dart test --coverage=coverage
dart run coverage:format_coverage --lcov --in=coverage --out=coverage/lcov.info --report-on=lib --package=.

# Flutter
flutter test --coverage
  1. Open a source file — coverage appears automatically

Or use CoverLens: Run Tests with Coverage (Cmd+Shift+P) to generate coverage and visualize in one step.

Coverage States

State Color Meaning
Covered Green Line executed, all branches taken
Partial Yellow Line executed, but some branches not taken
Uncovered Red Line never executed

Most coverage tools only show binary covered/uncovered. CoverLens shows partial branch coverage as a distinct state — helping you find untested edge cases.

Display Modes

Border mode (default)

Minimal vertical bar on the left edge — clean, non-intrusive, works great with any theme.

Border mode

Highlight mode

Vertical bar + background fill — maximum visibility for reviewing coverage.

Highlight mode

Set via coverlens.decorationStyle. Both modes use line decorations (not gutter icons), so they never conflict with debugger breakpoints — you can set breakpoints freely while coverage is visible.

Diff Mode

Focus on what matters during code review — show coverage only on lines you changed.

CoverLens: Toggle Diff Mode

Uses git diff against a configurable base ref:

"coverlens.diffBase": "origin/main"

Monorepo Support

CoverLens automatically detects packages from:

  • pnpm-workspace.yaml
  • package.json workspaces (npm/yarn)

Coverage from all packages is aggregated into one unified view. Configure manually if needed:

"coverlens.monorepo.packages": ["packages/*", "apps/*"]

Commands

Command Description
CoverLens: Toggle Coverage Show or hide coverage decorations
CoverLens: Toggle Diff Mode Switch between all-lines and changed-lines view
CoverLens: Run Tests with Coverage Execute test runner and reload coverage
CoverLens: Reload Coverage Files Re-read coverage files from disk
CoverLens: Show Coverage Summary Display current coverage % and delta
CoverLens: Stop Running Tests Cancel the currently running test suite
CoverLens: Reset Coverage Baseline Reset the session baseline for delta tracking

Settings

Setting Default Description
coverlens.enabled true Enable coverage visualization on startup
coverlens.coverageFiles ["**/lcov.info", ...] Glob patterns to find coverage files
coverlens.excludePatterns ["**/node_modules/**", ...] Patterns to exclude from search
coverlens.decorationStyle "border" Display mode: "border" or "highlight"
coverlens.overviewRuler false Show coverage colors in the scrollbar
coverlens.onEdit "dim" Stale coverage behavior: "hide", "dim", or "keep"
coverlens.runOnSave "package" Auto-run tests on save: "off", "package" (affected package only), or "all" (full suite)
coverlens.colors.covered — Custom color for covered lines
coverlens.colors.partial — Custom color for partial branch lines
coverlens.colors.uncovered — Custom color for uncovered lines
coverlens.diffMode false Show coverage only for changed lines
coverlens.diffBase "HEAD" Git ref for diff mode comparison
coverlens.testRunner.mode "auto" Test runner: auto, jest, vitest, pytest, go, cargo, dotnet, dart, flutter, custom
coverlens.testRunner.customCommand — Custom shell command for test runner
coverlens.monorepo.enabled true Auto-detect monorepo packages
coverlens.monorepo.packages [] Manual package glob patterns
coverlens.thresholds.low 50 Below this % coverage → red icon in tree
coverlens.thresholds.medium 80 Below this % coverage → yellow icon in tree
coverlens.showDelta true Show coverage delta in status bar

Default Coverage File Patterns

CoverLens searches for these files automatically:

**/lcov.info                    LCOV (Jest, Vitest, pytest, Dart, Flutter, tarpaulin, Coverlet)
**/coverage.lcov                LCOV (alternative name)
**/coverage.xml                 Cobertura XML (coverage.py, Coverlet)
**/coverage.cobertura.xml       Cobertura XML (.NET)
**/jacoco.xml                   JaCoCo XML (Java/Kotlin)
**/target/site/jacoco/jacoco.xml  JaCoCo XML (Maven default)
**/coverage.out                 Go coverage profile
**/*.coverprofile               Go coverage profile (alternative)
**/coverage.json                Istanbul JSON (Jest, NYC, c8)
**/coverage-final.json          Istanbul JSON (NYC default)

Add custom patterns in settings if your tool outputs to a different path.

License

MIT