build: use nyc for test coverage

.gitignore

@@ -1,3 +1,4 @@
+.nyc_output/
 coverage/
 node_modules/
 npm-debug.log

.travis.yml

@@ -64,10 +64,6 @@ before_install:
     # Configure eslint for linting
     if node_version_lt '10.0'; then npm_remove_module_re '^eslint(-|$)'
     fi
-  - |
-    # Configure istanbul for coverage
-    if node_version_lt '0.10'; then npm_remove_module_re '^istanbul$'
-    fi
   - |
     # Configure mocha for testing
     if   node_version_lt '0.10'; then npm_use_module 'mocha' '2.5.3'
@@ -76,6 +72,13 @@ before_install:
     elif node_version_lt '8.0' ; then npm_use_module 'mocha' '6.2.2'
     elif node_version_lt '10.0'; then npm_use_module 'mocha' '7.2.0'
     fi
+  - |
+    # Configure nyc for coverage
+    if   node_version_lt '0.10'; then npm_remove_module_re '^nyc$'
+    elif node_version_lt '4.0' ; then npm_use_module 'nyc' '10.3.2'
+    elif node_version_lt '6.0' ; then npm_use_module 'nyc' '11.9.0'
+    elif node_version_lt '8.0' ; then npm_use_module 'nyc' '14.1.1'
+    fi
   - |
     # Configure supertest for http calls
     if   node_version_lt '0.10'; then npm_use_module 'supertest' '1.1.0'
@@ -90,9 +93,9 @@ before_install:
       npm rebuild
     fi
 script:
-  # Run test script, depending on istanbul install
+  # Run test script, depending on nyc install
   - |
-    if npm_module_installed 'istanbul'; then npm run-script test-travis
+    if npm_module_installed 'nyc'; then npm run-script test-ci
     else npm test
     fi
   # Run linting, depending on eslint install
@@ -102,7 +105,7 @@ script:
 after_script:
   # Upload coverage to coveralls if exists
   - |
-    if [[ -f ./coverage/lcov.info ]]; then
+    if [[ -d .nyc_output ]]; then
       npm install --save-dev coveralls@2
-      coveralls < ./coverage/lcov.info
+      nyc report --reporter=text-lcov | coveralls
     fi

package.json

@@ -22,8 +22,8 @@
     "eslint": "7.26.0",
     "eslint-plugin-markdown": "2.1.0",
     "finalhandler": "1.1.2",
-    "istanbul": "0.4.5",
     "mocha": "8.4.0",
+    "nyc": "15.1.0",
     "safe-buffer": "5.2.1",
     "supertest": "6.1.3"
   },
@@ -40,8 +40,8 @@
   "scripts": {
     "lint": "eslint .",
     "test": "mocha --reporter spec --bail --check-leaks test/",
-    "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --reporter dot --check-leaks test/",
-    "test-travis": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --reporter spec --check-leaks test/",
+    "test-ci": "nyc --reporter=html --reporter=text npm test",
+    "test-cov": "nyc --reporter=text npm test",
     "version": "node scripts/version-history.js && git add HISTORY.md"
   }
 }