Improve code quality and write tests

node_modules/codecov/lib/services/buildkite.js

@@ -0,0 +1,18 @@
+module.exports = {
+  detect: function() {
+    return !!process.env.BUILDKITE
+  },
+
+  configuration: function() {
+    // https://buildkite.com/docs/guides/environment-variables
+    console.log('    Buildkite CI Detected')
+    return {
+      service: 'buildkite',
+      build: process.env.BUILDKITE_BUILD_NUMBER,
+      build_url: process.env.BUILDKITE_BUILD_URL,
+      commit: process.env.BUILDKITE_COMMIT,
+      branch: process.env.BUILDKITE_BRANCH,
+      slug: process.env.BUILDKITE_PROJECT_SLUG,
+    }
+  },
+}