diff --git a/.travis.yml b/.travis.yml
index f1458688c..fdb99dfa3 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,14 +8,12 @@ addons:
     sources:
       - ubuntu-toolchain-r-test
     packages:
-      - libglew-dev # required by node-gl.
+      - libglew-dev # required by headless-gl.
       - libopenal-dev
       - libalut-dev
       - libxxf86vm-dev
 
 before_install:
-  - export DISPLAY=:99.0
-  - sh -e /etc/init.d/xvfb start
   - export NODE_PATH=$(npm config get prefix)/lib/node_modules
   - npm install --global gl
 
@@ -24,11 +22,18 @@ install:
   - go get github.com/gopherjs/gopherjs
   - go get github.com/gopherjs/webgl
 
+before_script:
+  - export DISPLAY=:99.0
+  - sh -e /etc/init.d/xvfb start
+  - sleep 3
+
 script:
   - go test -v ./...
-  - gopherjs test -v github.com/hajimehoshi/ebiten github.com/hajimehoshi/ebiten/internal/graphics
   - gopherjs build -v github.com/hajimehoshi/ebiten/example/blocks
 
+# Looks like testing GL on node on Travis CI seems hard.
+# - gopherjs test -v github.com/hajimehoshi/ebiten github.com/hajimehoshi/ebiten/internal/graphics
+
 notifications:
   email:
     recipients:
diff --git a/internal/graphics/opengl/context_js.go b/internal/graphics/opengl/context_js.go
index 335cf141b..3a8c874d1 100644
--- a/internal/graphics/opengl/context_js.go
+++ b/internal/graphics/opengl/context_js.go
@@ -83,7 +83,11 @@ func NewContext() *Context {
 		}
 	} else {
 		// Use headless-gl for testing.
-		webglContext := js.Global.Call("require", "gl").Invoke(16, 16)
+		options := map[string]bool{
+			"alpha":              true,
+			"premultipliedAlpha": true,
+		}
+		webglContext := js.Global.Call("require", "gl").Invoke(16, 16, options)
 		gl = &webgl.Context{Object: webglContext}
 	}