write custom test reporter for more verbose output

Implemented a simple custom mocha test reporter to replace the default
one. Made test report more developer friendly.

package.json

@@ -45,6 +45,6 @@
   },
   "scripts": {
     "lint": "standard */*.js test/**/*.js",
-    "test": "npm run lint && mocha test/test-download.js test/test-*"
+    "test": "npm run lint && mocha --reporter=test/reporter.js test/test-download.js test/test-*"
   }
 }

test/reporter.js

@@ -0,0 +1,75 @@
+const Mocha = require('mocha')
+
+class Reporter {
+  constructor (runner) {
+    this.failedTests = []
+
+    runner.on(Mocha.Runner.constants.EVENT_RUN_BEGIN, () => {
+      console.log('Starting tests')
+    })
+
+    runner.on(Mocha.Runner.constants.EVENT_RUN_END, () => {
+      console.log('Tests finished')
+      console.log()
+      console.log('****************')
+      console.log('* TESTS REPORT *')
+      console.log('****************')
+      console.log()
+      console.log(`Executed ${runner.stats.suites} suites with ${runner.stats.tests} tests in ${runner.stats.duration} ms`)
+      console.log(`  Passed: ${runner.stats.passes}`)
+      console.log(`  Skipped: ${runner.stats.pending}`)
+      console.log(`  Failed: ${runner.stats.failures}`)
+      if (this.failedTests.length > 0) {
+        console.log()
+        console.log('  Failed test details')
+        this.failedTests.forEach((failedTest, index) => {
+          console.log()
+          console.log(`    ${index + 1}. '${failedTest.test.fullTitle()}'`)
+          console.log(`      Name: ${failedTest.error.name}`)
+          console.log(`      Message: ${failedTest.error.message}`)
+          console.log(`      Code: ${failedTest.error.code}`)
+          console.log(`      Stack: ${failedTest.error.stack}`)
+        })
+      }
+      console.log()
+    })
+
+    runner.on(Mocha.Runner.constants.EVENT_SUITE_BEGIN, (suite) => {
+      if (suite.root) {
+        return
+      }
+      console.log(`Starting suite '${suite.title}'`)
+    })
+
+    runner.on(Mocha.Runner.constants.EVENT_SUITE_END, (suite) => {
+      if (suite.root) {
+        return
+      }
+      console.log(`Suite '${suite.title}' finished`)
+      console.log()
+    })
+
+    runner.on(Mocha.Runner.constants.EVENT_TEST_BEGIN, (test) => {
+      console.log(`Starting test '${test.title}'`)
+    })
+
+    runner.on(Mocha.Runner.constants.EVENT_TEST_PASS, (test) => {
+      console.log(`Test '${test.title}' passed in ${test.duration} ms`)
+    })
+
+    runner.on(Mocha.Runner.constants.EVENT_TEST_PENDING, (test) => {
+      console.log(`Test '${test.title}' skipped in ${test.duration} ms`)
+    })
+
+    runner.on(Mocha.Runner.constants.EVENT_TEST_FAIL, (test, error) => {
+      this.failedTests.push({ test, error })
+      console.log(`Test '${test.title}' failed in ${test.duration} ms with ${error}`)
+    })
+
+    runner.on(Mocha.Runner.constants.EVENT_TEST_END, (test) => {
+      console.log()
+    })
+  }
+}
+
+module.exports = Reporter