diff --git a/.travis.yml b/.travis.yml
index fa30a20c6..fedfd4461 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,12 +4,14 @@ go:
   - 1.4
 
 before_install:
-  - "export DISPLAY=:99.0"
-  - "sh -e /etc/init.d/xvfb start"
+  - export DISPLAY=:99.0
+  - sh -e /etc/init.d/xvfb start
   - sudo add-apt-repository 'deb http://us.archive.ubuntu.com/ubuntu/ utopic main restricted universe multiverse'
   - sudo add-apt-repository 'deb http://us.archive.ubuntu.com/ubuntu/ utopic-updates main restricted universe multiverse'
   - sudo apt-get update -qq
   - sudo apt-get install -qq libglew-dev libglfw3-dev
+  - export NODE_PATH=$(npm config get prefix)/lib/node_modules
+  - npm install --global gl
 
 install:
   - go get -t -v ./...
@@ -18,6 +20,7 @@ install:
 
 script:
   - go test -v ./...
+  - gopherjs test -v github.com/hajimehoshi/ebiten github.com/hajimehoshi/ebiten/internal
   - gopherjs build -v github.com/hajimehoshi/ebiten/example/blocks
 
 notifications:
diff --git a/image_test.go b/image_test.go
index c9bcba860..6beb5f2b2 100644
--- a/image_test.go
+++ b/image_test.go
@@ -19,16 +19,16 @@ import (
 	"image"
 	"image/color"
 	_ "image/png"
-	"os"
 	"testing"
 )
 
+var ebitenImageBin = ""
+
 func openImage(path string) (*Image, image.Image, error) {
-	file, err := os.Open(path)
+	file, err := readFile(path)
 	if err != nil {
 		return nil, nil, err
 	}
-	defer file.Close()
 
 	img, _, err := image.Decode(file)
 	if err != nil {
diff --git a/internal/opengl/context_js.go b/internal/opengl/context_js.go
index 45cbc161a..b6ef1a584 100644
--- a/internal/opengl/context_js.go
+++ b/internal/opengl/context_js.go
@@ -112,6 +112,10 @@ func (c *Context) DeleteTexture(t Texture) {
 
 func (c *Context) GlslHighpSupported() bool {
 	gl := c.gl
+	// node-gl library may not define getShaderPrecisionFormat.
+	if gl.Get("getShaderPrecisionFormat") == js.Undefined {
+		return false
+	}
 	return gl.Call("getShaderPrecisionFormat", gl.FRAGMENT_SHADER, gl.HIGH_FLOAT).Get("precision").Int() != 0
 }
 
diff --git a/internal/ui/ui_js.go b/internal/ui/ui_js.go
index 712a93ba3..a6efeffbf 100644
--- a/internal/ui/ui_js.go
+++ b/internal/ui/ui_js.go
@@ -64,7 +64,13 @@ func SwapBuffers() {
 }
 
 func init() {
-	// TODO: Implement this with node-webgl mainly for testing.
+	if js.Global.Get("require") != js.Undefined {
+		// Use headless-gl for testing.
+		nodeGl := js.Global.Call("require", "gl")
+		webglContext := nodeGl.Call("createContext", 16, 16)
+		context = opengl.NewContext(&webgl.Context{Object: webglContext})
+		return
+	}
 
 	doc := js.Global.Get("document")
 	window := js.Global.Get("window")
diff --git a/util_test.go b/util_test.go
new file mode 100644
index 000000000..e910c095b
--- /dev/null
+++ b/util_test.go
@@ -0,0 +1,124 @@
+// Copyright 2014 Hajime Hoshi
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ebiten_test
+
+import (
+	"bytes"
+	"encoding/base64"
+	"errors"
+	"github.com/gopherjs/gopherjs/js"
+	"io"
+	"io/ioutil"
+	"strings"
+)
+
+// NOTE: Please update if any of testdata/* is updated.
+var data = map[string]string{
+	"testdata/ebiten.png": `
+iVBORw0KGgoAAAANSUhEUgAAADkAAAAaCAYAAAANIPQdAAAEJGlDQ1BJQ0Mg
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+SUVORK5CYII=`,
+}
+
+func readFile(path string) (io.Reader, error) {
+	if js.Global == nil {
+		b, err := ioutil.ReadFile(path)
+		if err != nil {
+			return nil, err
+		}
+		return bytes.NewBuffer(b), nil
+	}
+	// According to https://github.com/gopherjs/gopherjs/blob/master/doc/syscalls.md,
+	// syscall can be available on the unstable version of npm.
+	// Let's not use os package here.
+	str, ok := data[path]
+	if !ok {
+		return nil, errors.New("not found")
+	}
+	return base64.NewDecoder(base64.StdEncoding, strings.NewReader(str)), nil
+}