add nyc and coveralls

.gitignore

@@ -1 +1,3 @@
 node_modules
+coverage
+.nyc_output

.travis.yml

@@ -21,3 +21,5 @@ matrix:
 
 script:
   - DEBUG=airtap:* npm run $CMD
+
+after_success: npm run coverage

README.md

@@ -7,6 +7,7 @@
 ![Node version](https://img.shields.io/node/v/abstract-leveldown.svg)
 [![Travis](https://travis-ci.org/Level/abstract-leveldown.svg?branch=master)](http://travis-ci.org/Level/abstract-leveldown)
 [![david](https://david-dm.org/Level/abstract-leveldown.svg)](https://david-dm.org/level/abstract-leveldown)
+[![Coverage Status](https://coveralls.io/repos/github/Level/abstract-leveldown/badge.svg)](https://coveralls.io/github/Level/abstract-leveldown)
 [![JavaScript Style Guide](https://img.shields.io/badge/code_style-standard-brightgreen.svg)](https://standardjs.com)
 [![npm](https://img.shields.io/npm/dm/abstract-leveldown.svg)](https://www.npmjs.com/package/abstract-leveldown)
 

package.json

@@ -20,14 +20,17 @@
   },
   "devDependencies": {
     "airtap": "0.1.0",
+    "coveralls": "~3.0.2",
+    "nyc": "~12.0.2",
     "sinon": "^6.0.0",
     "standard": "^11.0.0",
     "tape": "^4.7.0"
   },
   "scripts": {
-    "test": "standard && node test.js",
-    "test-browsers": "airtap --loopback airtap.local test.js",
-    "test-browser-local": "airtap --local test.js"
+    "test": "standard && nyc node test.js",
+    "test-browsers": "airtap --coverage --loopback airtap.local test.js",
+    "test-browser-local": "airtap --coverage --local test.js",
+    "coverage": "nyc report --reporter=text-lcov | coveralls"
   },
   "browser": {
     "./test-common.js": "./test-common-browser.js"