nvim-coverage

A Neovim plugin that displays code coverage from lcov files directly in the editor — sign column markers, highlight groups, a summary popup, virtual text hit counts, branch overlays, and quickfix/loclist navigation.

Built on the foundation of andythigpen/nvim-coverage, stripped down and focused exclusively on lcov.

Features

• Sign column markers for covered, uncovered, and partially covered lines
• Branch coverage support (partial signs) with per-branch overlay popup
• Virtual text showing execution hit counts per line
• Coverage summary popup with per-file stats, sortable by coverage
• Quickfix list (per-file summary) and location list (per-line) navigation
• Auto-reload when the lcov file changes on disk
• Works with any language that produces lcov output

Requirements

• Neovim >= 0.9
• plenary.nvim

Installation

lazy.nvim

{
  "nvim-contrib/nvim-coverage",
  dependencies = { "nvim-lua/plenary.nvim" },
  config = function()
    require("coverage").setup()
  end,
}

packer.nvim

use({
  "nvim-contrib/nvim-coverage",
  requires = "nvim-lua/plenary.nvim",
  config = function()
    require("coverage").setup()
  end,
})

Generating lcov files

The plugin reads a pre-generated lcov file — it does not run tests or invoke any tools itself.

By default the plugin searches for an lcov file in these locations (first existing file wins):

lcov.info
cover/lcov.info
coverage/lcov.info
target/lcov.info

Override with the file option if your tool writes elsewhere.

Language	Command	Default output path
Go	go test -coverprofile=coverage.out ./... && go tool cover -o coverage/lcov.info coverage.out	coverage/lcov.info
Rust	cargo +nightly llvm-cov --lcov --branch --output-path target/lcov.info	target/lcov.info
JavaScript/TypeScript	jest --coverage	coverage/lcov.info
Python	pytest --cov && coverage lcov -o coverage/lcov.info	coverage/lcov.info
C/C++	lcov --capture --directory . --output-file lcov.info	lcov.info
Swift	xcrun xccov view --report --json ... | <converter>	coverage/lcov.info

Configuration

require("coverage").setup({
  -- path (or list of paths) to the lcov file; first existing file wins
  -- defaults to: { "lcov.info", "cover/lcov.info", "coverage/lcov.info", "target/lcov.info" }
  -- file = "coverage/lcov.info",

  -- register :Coverage* commands (default: true)
  commands = true,

  auto_reload = {
    enabled = false,    -- auto-reload signs when lcov file changes on disk
    timeout_ms = 500,   -- debounce delay before reloading
  },

  -- called after coverage is loaded
  on_load = nil,

  signs = {
    covered   = { hl = "CoverageCovered",   text = "▎" },
    uncovered = { hl = "CoverageUncovered", text = "▎" },
    partial   = { hl = "CoveragePartial",   text = "▎" },
    group     = "coverage",  -- sign group name (:h sign-group)
  },

  highlights = {
    covered   = { fg = "#B7F071" },
    uncovered = { fg = "#F07178" },
    partial   = { fg = "#AA71F0" },
  },

  report = {
    width        = 0.70,
    height       = 0.50,
    min_coverage = 80.0, -- threshold for pass/fail highlight in report
    window       = {},   -- extra options passed to the popup window
    highlights = {
      border      = { link = "FloatBorder" },
      normal      = { link = "NormalFloat" },
      cursor_line = { link = "CursorLine" },
      header      = { style = "bold,underline", sp = "fg" },
      pass        = { link = "CoverageCovered" },
      fail        = { link = "CoverageUncovered" },
    },
  },

  line_hits = {
    enabled   = false,  -- show hit counts automatically after load
    position  = "eol",  -- "eol" | "right_align" | "inline"
    highlight = { link = "Comment" },
  },
})

Usage

Commands

Command	Description
:CoverageLoad [file]	Load lcov file and cache signs (uses file config if no arg)
:CoverageLoad!	Open interactive picker over all *.info files found under cwd
:CoverageSigns [show|hide|toggle]	Show, hide, or toggle line signs (default: toggle)
:CoverageHints [show|hide|toggle]	Show, hide, or toggle line hints / virtual text hit counts (default: toggle)
:CoverageBranches [show|hide|toggle]	Show, hide, or toggle branch hints popup (default: toggle)
:CoverageClear	Remove signs, hints, and branch overlay; clear cache; stop file watcher
:CoverageReport	Open the summary popup
:CoverageHeatmap	Open full-screen treemap — files sized by LOC, colored by coverage %
:CoverageQuickfix [uncovered]	Populate quickfix list with per-file coverage summary
:CoverageLoclist [uncovered|partial]	Populate location list with lines of given type in current buffer
:CoverageBrowser	Generate HTML report via genhtml and open in browser

Lua API

local coverage = require("coverage")

-- load
coverage.load()                          -- load from config.file
coverage.load("path/to/lcov.info")       -- load from explicit path
coverage.load("path/to/lcov.info", true) -- load and immediately show signs

-- line signs
coverage.show_line_signs()
coverage.hide_line_signs()
coverage.toggle_line_signs()
coverage.clear()

-- summary popup
coverage.report()

-- treemap heatmap
coverage.heatmap()

-- line hints — shows execution hit counts (e.g. × 42) on every instrumented line
coverage.show_line_hints()
coverage.hide_line_hints()
coverage.toggle_line_hints()

-- branch hints — floating popup on partial lines showing per-branch counts
coverage.show_branch_hints()
coverage.hide_branch_hints()
coverage.toggle_branch_hints()

-- quickfix / loclist navigation
coverage.quickfix()             -- all files, sorted by coverage ascending
coverage.quickfix("uncovered")  -- only files with uncovered lines
coverage.loclist()              -- uncovered lines in current buffer
coverage.loclist("partial")     -- partially covered lines in current buffer

-- jump to next/previous sign
coverage.jump_next("uncovered")  -- "covered" | "uncovered" | "partial"
coverage.jump_prev("uncovered")

Summary popup keys

Key	Action
s	Sort by coverage ascending
S	Sort by coverage descending
H	Jump to top entry
<CR>	Open file under cursor
?	Toggle help
q / <Esc>	Close

Quickfix / loclist workflow

:CoverageQuickfix uncovered   → quickfix list of files with gaps, worst first
:CoverageLoclist              → location list of uncovered lines in current file
:CoverageLoclist partial      → location list of partially covered lines

Navigate the quickfix list with :cnext / :cprev (or ]q / [q with a mapping). Navigate the location list with :lnext / :lprev.

neotest integration

The plugin ships built-in neotest consumers so coverage reloads automatically after every test run.

Generic consumer — works for any language that writes an lcov file during the test run (e.g. Rust with cargo-llvm-cov):

require("neotest").setup({
  consumers = {
    coverage = require("coverage.neotest"),
  },
})

Go consumer — converts coverage.out to lcov.info in pure Lua, then reloads. Expects tests to be run with -coverprofile=coverage.out:

require("neotest").setup({
  consumers = {
    coverage_go = require("coverage.neotest.go"),
  },
})

Python consumer — converts .coverage (coverage.py database) to coverage/lcov.info via python -m coverage lcov, then reloads. Requires coverage[toml] and pytest-cov to be installed.

Enable coverage collection by adding to your pyproject.toml:

[tool.pytest.ini_options]
addopts = "--cov"

Then register the consumer:

require("neotest").setup({
  consumers = {
    coverage_python = require("coverage.neotest.python"),
  },
})

All consumers can be combined:

require("neotest").setup({
  consumers = {
    coverage        = require("coverage.neotest"),
    coverage_go     = require("coverage.neotest.go"),
    coverage_python = require("coverage.neotest.python"),
  },
})

Contributing

Contributions are welcome. Please open an issue or pull request.

License

MIT