build: install nyc on demand

.travis.yml

@@ -56,8 +56,7 @@ before_install:
   - "npm config set shrinkwrap false"
 
   # Setup Node.js version-specific dependencies
-  - "test $TRAVIS_NODE_VERSION != '0.6' || npm rm --save-dev nyc"
-  - "test $TRAVIS_NODE_VERSION != '0.8' || npm rm --save-dev nyc"
+  - "node tool/install-nyc.js --nyc-optional"
   - "test $(echo $TRAVIS_NODE_VERSION | cut -d. -f1) -ge 4 || npm rm --save-dev eslint"
 
   # Update Node.js modules
@@ -78,10 +77,9 @@ before_script:
   - "docker exec mysql mysql -e 'select version()'"
 
 script:
-  # Run test script, depending on nyc install
-  - "test ! -z $(npm -ps ls nyc) || npm test"
-  - "test   -z $(npm -ps ls nyc) || npm run-script test-ci"
-  - "test   -z $(npm -ps ls eslint) || npm run-script lint"
+  # Run test script
+  - "npm run-script test-ci"
+  - "test -z $(npm -ps ls eslint) || npm run-script lint"
 
 after_script:
   - "test -d .nyc_output && npm install coveralls@2 && nyc report --reporter=text-lcov | coveralls"

appveyor.yml

@@ -32,7 +32,7 @@ install:
       catch { Update-NodeJsInstallation (Get-NodeJsLatestBuild $env:nodejs_version) }
   - npm config set shrinkwrap false
   - if "%nodejs_version%" equ "0.8" npm config set strict-ssl false
-  - npm rm --silent --save-dev eslint nyc
+  - npm rm --silent --save-dev eslint
   - if exist node_modules npm prune
   - if exist node_modules npm rebuild
   - npm install

package.json

@@ -21,7 +21,6 @@
   "devDependencies": {
     "after": "0.8.2",
     "eslint": "4.19.1",
-    "nyc": "10.3.2",
     "seedrandom": "2.4.4",
     "timezone-mock": "0.0.7",
     "urun": "0.0.8",
@@ -40,8 +39,8 @@
   "scripts": {
     "lint": "eslint .",
     "test": "node test/run.js",
-    "test-ci": "nyc --reporter=text npm test",
-    "test-cov": "nyc --reporter=html --reporter=text npm test",
+    "test-ci": "node tool/install-nyc.js --nyc-optional --reporter=text -- npm test",
+    "test-cov": "node tool/install-nyc.js --reporter=html --reporter=text -- npm test",
     "version": "node tool/version-changes.js && git add Changes.md"
   }
 }