diff --git a/.travis.yml b/.travis.yml
index 862a283..e484277 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,20 +2,28 @@ language: go
 
 go: 
  - 1.13
- 
+
+env: GO111MODULE=on
 arch:
   - amd64
   - arm64
-
 os:
   - windows
   - osx
   - linux
 
-env: GO111MODULE=on
+script: sh scripts/build.sh $TRAVIS_OS_NAME $TRAVIS_CPU_ARCH
 
-script:
-  - sh scripts/build.sh $TRAVIS_OS_NAME $TRAVIS_CPU_ARCH
+jobs:
+  include:
+    - stage: "Unit Tests"
+      arch:
+        - amd64
+      os:
+        - linux
+      script:
+        - go test -v -cover encoder_test.go encoder.go helper.go
+        - go test -v -cover helper_test.go helper.go
 
 deploy:
   provider: releases
diff --git a/encoder_test.go b/encoder_test.go
new file mode 100644
index 0000000..848e5f3
--- /dev/null
+++ b/encoder_test.go
@@ -0,0 +1,51 @@
+package main
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+//go test -v -cover encoder_test.go encoder.go helper.go
+func TestWebpEncoder(t *testing.T) {
+
+	var webp = "/tmp/test-result.webp"
+	var target = walker()
+
+	for _, f := range target {
+		//fmt.Println(b, c, webp)
+		runEncoder(t, f, webp)
+	}
+	_ = os.Remove(webp)
+
+}
+
+func walker() []string {
+	var list []string
+	_ = filepath.Walk("./pics", func(path string, info os.FileInfo, err error) error {
+		if !info.IsDir() {
+			list = append(list, path)
+		}
+		return nil
+	})
+	return list
+}
+
+func runEncoder(t *testing.T, file string, webp string) {
+	var c chan int
+	//t.Logf("Convert from %s to %s", file, webp)
+	var err = WebpEncoder(file, webp, 80, false, c)
+	if file == "pics/empty.jpg" && err != nil {
+		t.Log("Empty file, that's okay.")
+	} else if err != nil {
+		t.Fatalf("Fatal, convert failed for %s: %v ", file, err)
+	}
+
+	data, _ := ioutil.ReadFile(webp)
+	types := GetFileContentType(data[:512])
+	if types != "image/webp" {
+		t.Fatal("Fatal, file type is wrong!")
+	}
+
+}
diff --git a/helper.go b/helper.go
index 324bab8..5e63526 100644
--- a/helper.go
+++ b/helper.go
@@ -2,7 +2,6 @@ package main
 
 import (
 	"fmt"
-	"github.com/gofiber/fiber"
 	log "github.com/sirupsen/logrus"
 	"net/http"
 	"os"
@@ -62,34 +61,8 @@ func GenWebpAbs(RawImagePath string, ExhaustPath string, ImgFilename string, req
 	return cwd, WebpAbsolutePath
 }
 
-func CheckUA(c *fiber.Ctx, RawImageAbs string) (string, bool) {
-	// reference: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/User-Agent/Firefox
-	// https://developer.chrome.com/multidevice/user-agent#chrome_for_ios_user_agent
-	// Chrome
-	// ✅ Windows: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.61 Safari/537.36
-	// ✅ macOS:   Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.61 Safari/537.36
-	// ✅ Linux:   Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.61 Safari/537.36
-	// ✅ iOS:     Mozilla/5.0 (iPhone; CPU iPhone OS 13_5 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/83.0.4103.63 Mobile/15E148 Safari/604.1
-	// ✅ Android: Mozilla/5.0 (Linux; Android 10) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.60 Mobile Safari/537.36
-
-	// Firefox
-	// ✅ Windows: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:76.0) Gecko/20100101 Firefox/76.0
-	// ✅ macOS:   Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:76.0) Gecko/20100101 Firefox/76.0
-	// ✅ Linux:   Mozilla/5.0 (X11; Linux i686; rv:76.0) Gecko/20100101 Firefox/76.0
-	// ✅ iOS:     Mozilla/5.0 (iPad; CPU OS 10_15_4 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) FxiOS/25.0 Mobile/15E148 Safari/605.1.15
-	// ✅ Android: Mozilla/5.0 (Android 10; Mobile; rv:68.0) Gecko/68.0 Firefox/68.0
-
-	// Safari
-	// ❎ macOS: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.1 Safari/605.1.15
-	// ❎ iOS:   Mozilla/5.0 (iPad; CPU OS 13_5 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.1.1 Mobile/15E148 Safari/604.1
-
-	// WeChat
-	// ❎ iOS:     Mozilla/5.0 (iPhone; CPU iPhone OS 10_3_3 like Mac OS X) AppleWebKit/603.3.8 (KHTML, like Gecko) Mobile/14G60 wxwork/2.1.5 MicroMessenger/6.3.22
-	// ✅ Windows: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36 MicroMessenger/6.5.2.501 NetType/WIFI WindowsWechat QBCore/3.43.691.400 QQBrowser/9.0.2524.400
-	// ✅ Android: Mozilla/5.0 (Linux; Android 7.0; LG-H831 Build/NRD90U; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/68.0.3440.91 Mobile Safari/537.36 MicroMessenger/6.6.7.1303(0x26060743) NetType/WIFI Language/zh_TW
-
-	UA := c.Get("User-Agent")
-
+func isSafari(UA string) bool {
+	// for more information, please check test case
 	if strings.Contains(UA, "Firefox") || strings.Contains(UA, "Chrome") {
 		// Chrome or firefox on macOS Windows
 	} else if strings.Contains(UA, "Android") || strings.Contains(UA, "Windows") || strings.Contains(UA, "Linux") {
@@ -97,9 +70,7 @@ func CheckUA(c *fiber.Ctx, RawImageAbs string) (string, bool) {
 	} else if strings.Contains(UA, "FxiOS") || strings.Contains(UA, "CriOS") {
 		//firefox and Chrome on iOS
 	} else {
-		log.Infof("A Safari user has arrived...%s", UA)
-		c.SendFile(RawImageAbs)
-		return "", true
+		return true
 	}
-	return UA, false
+	return false
 }
diff --git a/helper_test.go b/helper_test.go
new file mode 100644
index 0000000..33b2170
--- /dev/null
+++ b/helper_test.go
@@ -0,0 +1,97 @@
+package main
+
+import (
+	"strings"
+	"testing"
+)
+
+// test this file: go test -v -cover helper_test.go helper.go
+// test one function: go test -run TestGetFileContentType helper_test.go helper.go -v
+func TestGetFileContentType(t *testing.T) {
+	var data = []byte("hello")
+	var expected = "text/plain; charset=utf-8"
+	var result = GetFileContentType(data)
+
+	if result != expected {
+		t.Errorf("Result: [%s], Expected: [%s]", result, expected)
+	}
+
+}
+
+// TODO: make a universal logging function
+func TestFileCount(t *testing.T) {
+	var data = ".github"
+	var expected = 2
+	var result = FileCount(data)
+
+	if result != expected {
+		t.Errorf("Result: [%d], Expected: [%d]", result, expected)
+	}
+}
+
+func TestImageExists(t *testing.T) {
+	var data = "./pics/empty.jpg"
+	var result = !ImageExists(data)
+
+	if result {
+		t.Errorf("Result: [%v], Expected: [%v]", result, false)
+	}
+	data = ".pics/empty2.jpg"
+	result = ImageExists(data)
+
+	if result {
+		t.Errorf("Result: [%v], Expected: [%v]", result, false)
+	}
+
+}
+
+func TestGenWebpAbs(t *testing.T) {
+	cwd, cooked := GenWebpAbs("./pics/webp_server.png", "/tmp",
+		"test", "a")
+	if !strings.Contains(cwd, "webp_server_go") {
+		t.Logf("Result: [%v], Expected: [%v]", cwd, "webp_server_go")
+	}
+	var parts = strings.Split(cooked, ".")
+	if parts[0] != "/tmp/test" || parts[2] != "webp" {
+		t.Errorf("Result: [%v], Expected: [%v]", cooked, "/tmp/test.<ts>.webp")
+
+	}
+}
+
+func TestisSafari(t *testing.T) {
+	// reference: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/User-Agent/Firefox
+	// https://developer.chrome.com/multidevice/user-agent#chrome_for_ios_user_agent
+
+	var testCase = map[string]bool{
+		// Chrome on Windows, macOS, linux, iOS and Android
+		"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.61 Safari/537.36":                            false,
+		"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.61 Safari/537.36":                      false,
+		"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.61 Safari/537.36":                                      false,
+		"Mozilla/5.0 (iPhone; CPU iPhone OS 13_5 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/83.0.4103.63 Mobile/15E148 Safari/604.1": false,
+		"Mozilla/5.0 (Linux; Android 10) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.60 Mobile Safari/537.36":                               false,
+
+		// Firefox on Windows, macOS, linux, iOS and Android
+		"Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:76.0) Gecko/20100101 Firefox/76.0":                                                     false,
+		"Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:76.0) Gecko/20100101 Firefox/76.0":                                                 false,
+		"Mozilla/5.0 (X11; Linux i686; rv:76.0) Gecko/20100101 Firefox/76.0":                                                                 false,
+		"Mozilla/5.0 (iPad; CPU OS 10_15_4 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) FxiOS/25.0 Mobile/15E148 Safari/605.1.15": false,
+		"Mozilla/5.0 (Android 10; Mobile; rv:68.0) Gecko/68.0 Firefox/68.0":                                                                  false,
+
+		// Safari on macOS and iOS
+		"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.1 Safari/605.1.15":            true,
+		"Mozilla/5.0 (iPad; CPU OS 13_5 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.1.1 Mobile/15E148 Safari/604.1": true,
+
+		// WeChat on iOS, Windows, and Android
+		"Mozilla/5.0 (iPhone; CPU iPhone OS 10_3_3 like Mac OS X) AppleWebKit/603.3.8 (KHTML, like Gecko) Mobile/14G60 wxwork/2.1.5 MicroMessenger/6.3.22":                                                                         true,
+		"Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36 MicroMessenger/6.5.2.501 NetType/WIFI WindowsWechat QBCore/3.43.691.400 QQBrowser/9.0.2524.400":              false,
+		"Mozilla/5.0 (Linux; Android 7.0; LG-H831 Build/NRD90U; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/68.0.3440.91 Mobile Safari/537.36 MicroMessenger/6.6.7.1303(0x26060743) NetType/WIFI Language/zh_TW": false,
+	}
+
+	for browser, is := range testCase {
+
+		if is != isSafari(browser) {
+			t.Errorf("[%v]:[%s]", is, browser)
+		}
+	}
+
+}
diff --git a/router.go b/router.go
index a99f1b1..abeda26 100644
--- a/router.go
+++ b/router.go
@@ -19,9 +19,11 @@ func Convert(ImgPath string, ExhaustPath string, AllowedTypes []string, QUALITY
 		var RawImageAbs = path.Join(ImgPath, reqURI) // /home/xxx/mypic/123.jpg
 		var ImgFilename = path.Base(reqURI)          // pure filename, 123.jpg
 		var finalFile string                         // We'll only need one c.sendFile()
-
-		UA, done := CheckUA(c, RawImageAbs)
+		var UA = c.Get("User-Agent")
+		done := isSafari(UA)
 		if done {
+			log.Infof("A Safari user has arrived...%s", UA)
+			c.SendFile(RawImageAbs)
 			return
 		}
 		log.Debugf("Incoming connection from %s@%s with %s", UA, c.IP(), ImgFilename)
diff --git a/scripts/unit_test.sh b/scripts/unit_test.sh
new file mode 100644
index 0000000..2900710
--- /dev/null
+++ b/scripts/unit_test.sh
@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+
+# bash scripts/unit_test.sh
+# check $? for success or failure
+go test -v -cover encoder_test.go encoder.go helper.go
+go test -v -cover helper_test.go helper.go
+
+# if [[ $? -ne 0 ]] ; then
+#  echo "TEST FAILED!!! PLEASE DOUBLE CHECK."
+# fi
diff --git a/update.go b/update.go
index e897d65..033b292 100644
--- a/update.go
+++ b/update.go
@@ -15,7 +15,7 @@ import (
 func autoUpdate() {
 	defer func() {
 		if err := recover(); err != nil {
-			log.Errorf("Download error.", err)
+			log.Errorf("Download error: %s", err)
 		}
 	}()
 
@@ -45,7 +45,7 @@ func autoUpdate() {
 	log.Info("Downloading binary to update...")
 	resp, _ := http.Get(releaseUrl)
 	if resp.StatusCode != 200 {
-		log.Debug("%s-%s not found on release.", runtime.GOOS, runtime.GOARCH)
+		log.Debugf("%s-%s not found on release.", runtime.GOOS, runtime.GOARCH)
 		return
 	}
 	data, _ := ioutil.ReadAll(resp.Body)
diff --git a/webp-server.go b/webp-server.go
index 46125e5..a56bee5 100644
--- a/webp-server.go
+++ b/webp-server.go
@@ -21,7 +21,7 @@ type Config struct {
 	ExhaustPath  string   `json:"EXHAUST_PATH"`
 }
 
-const version = "0.1.2"
+const version = "0.1.3"
 
 var configPath string
 var prefetch bool