Improve code quality and write tests

node_modules/codecov/test/detect.test.js

@@ -0,0 +1,17 @@
+var detect = require('../lib/detect')
+var git = require('../lib/git')
+
+describe('Codecov', function() {
+  it('can detect existing appveyor service', function() {
+    process.env.TRAVIS = 'true'
+
+    expect(detect().service).toBe('travis')
+
+    process.env.TRAVIS = ''
+  })
+
+  it('can select local git service if no service is found', function() {
+    expect(detect().commit).toMatch(/^\w{40}$/)
+    expect(detect().commit).toBe(git.head())
+  })
+})