Another attempt, with nyc this time

.babelrc

@@ -6,4 +6,13 @@
   ignore: [
     "packages/enzyme-test-suite/test/_helpers/untranspiled*",
   ],
+  "env": {
+    "test": {
+      "plugins": [
+        ["transform-replace-object-assign", { "moduleSpecifier": "object.assign" }],
+        "istanbul",
+      ],
+      "sourceMaps": "inline",
+    },
+  },
 }

.gitignore

@@ -12,6 +12,7 @@ lib-cov
 
 # Coverage directory used by tools like istanbul
 coverage
+.nyc_output
 
 # Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
 .grunt

.nycrc

@@ -0,0 +1,28 @@
+{
+	"all": true,
+	"cache": true,
+	"check-coverage": true,
+	"reporter": ["text-summary", "text", "html", "json"],
+	"extension": [".jsx", ".js"],
+	"sourceMap": false,
+	"instrument": false,
+	"lines": 100,
+	"statements": 100,
+	"functions": 100,
+	"branches": 100,
+	"exclude": [
+		"_book",
+		"coverage",
+		"docs",
+		"env.js",
+		"karma.conf.js",
+		"packages/enzyme/withDom.js",
+		"packages/enzyme-test-suite",
+		"packages/enzyme-example-mocha",
+		"since.js",
+		"test"
+	],
+	"require": [
+		"babel-register"
+	]
+}

package.json

@@ -36,6 +36,8 @@
     "docs:watch": "npm run docs:prepare && gitbook serve",
     "docs:publish": "npm run docs:clean && npm run docs:build && cd _book && git init && git commit --allow-empty -m 'update book' && git fetch git@github.com:airbnb/enzyme.git gh-pages && git checkout -b gh-pages && git add . && git commit -am 'update book' && git push git@github.com:airbnb/enzyme.git gh-pages --force",
     "pretravis": "npm run build",
+    "coverage": "NODE_ENV=test nyc _mocha packages/enzyme-test-suite/test --recursive",
+    "postcoverage": "nyc report",
     "travis": "babel-node \"$(which istanbul)\" cover --report html --report json _mocha -- packages/enzyme-test-suite/test --recursive",
     "since": "node since"
   },
@@ -64,6 +66,7 @@
     "babel-core": "^6.26.3",
     "babel-eslint": "^7.2.3",
     "babel-loader": "^6.4.1",
+    "babel-plugin-istanbul": "^4.1.6",
     "babel-plugin-transform-replace-object-assign": "^1.0.0",
     "babel-preset-airbnb": "^2.6.0",
     "babel-register": "^6.26.0",
@@ -94,10 +97,17 @@
     "karma-webpack": "^1.8.1",
     "lerna": "^2.11.0",
     "mocha": "^3.5.3",
+    "nyc": "^10.3.2",
     "prop-types": "^15.6.2",
     "rimraf": "^2.6.2",
     "safe-publish-latest": "^1.1.2",
     "webpack": "^1.15.0"
   },
-  "dependencies": {}
+  "dependencies": {},
+  "greenkeeper": {
+    "//": "nyc is ignored because it requires node 4+, and we support older than that",
+    "ignore": [
+      "nyc"
+    ]
+  }
 }