diff --git a/.gitignore b/.gitignore
index 22b85c8..1007419 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 .DS_Store
 main
+*.coverprofile
diff --git a/.travis.yml b/.travis.yml
index d931af1..483fc5a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,14 +3,28 @@ sudo: no
 go:
   - 1.9
 
-go_import_path:
-  - "github.com/tatsy/gopt"
+go_import_path: github.com/tatsy/gopt
+
+before_install:
+  - go get golang.org/x/tools/cmd/cover
+  - go get github.com/mattn/goveralls
+  - go get github.com/modocache/gover
 
 install:
-  make
+  - export GOPATH=$TRAVIS_BUILD_DIR
+  - go build ./...
 
 script:
-  make test
+  - go list -f '{{if len .TestGoFiles}}"go test -coverprofile={{.Dir}}/.coverprofile {{.ImportPath}}"{{end}}' ./... | xargs -L 1 sh -c
+
+after_success:
+  - $HOME/gopath/bin/gover
+  - $HOME/gopath/bin/goveralls -coverprofile=gover.coverprofile -service=travis-ci -repotoken $COVERALLS_REPO_TOKEN
+
+env:
+  global:
+    secure: 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
+
 
 branches:
   only:
diff --git a/Makefile b/Makefile
index 076fadc..5127c8d 100644
--- a/Makefile
+++ b/Makefile
@@ -1,11 +1,12 @@
 all:
-	go build src/main.go
+	export GOPATH=`pwd`
+	go build ./...
 
 run:
 	go run src/main.go
 
 test:
-	go test ./src/... --count 10 --cover
+	go test ./... -v --count 10 --cover
 
 clean:
-	rm -rf main image.jpg
+	rm -rf main *.jpg *.png
diff --git a/src/accelerator/bvh.go b/src/accelerator/bvh.go
index 046597e..9a9bdc6 100644
--- a/src/accelerator/bvh.go
+++ b/src/accelerator/bvh.go
@@ -2,7 +2,7 @@ package accelerator
 
 import (
     "sort"
-    . "../core"
+    . "core"
 )
 
 type BvhNode struct {
diff --git a/src/accelerator/bvh_test.go b/src/accelerator/bvh_test.go
index c169af3..d164cbb 100644
--- a/src/accelerator/bvh_test.go
+++ b/src/accelerator/bvh_test.go
@@ -5,9 +5,9 @@ import (
     "math"
     "math/rand"
     "testing"
-    . "../core"
-    . "../shape"
-    . "../bsdf"
+    . "core"
+    . "shape"
+    . "bsdf"
 )
 
 func TestAxisSorter(t *testing.T) {
diff --git a/src/bsdf/lambert.go b/src/bsdf/lambert.go
index 9f782b0..406cf29 100644
--- a/src/bsdf/lambert.go
+++ b/src/bsdf/lambert.go
@@ -2,7 +2,7 @@ package bsdf
 
 import (
     // "math"
-    . "../core"
+    . "core"
 )
 
 type LambertBsdf struct {
diff --git a/src/integrator/path.go b/src/integrator/path.go
index 36ed521..5efc2a4 100644
--- a/src/integrator/path.go
+++ b/src/integrator/path.go
@@ -1,8 +1,8 @@
 package integrator
 
 import (
-    . "../core"
-    . "../accelerator"
+    . "core"
+    . "accelerator"
 )
 
 type PathIntegrator struct {
diff --git a/src/main.go b/src/main.go
index 466ccc0..45a244b 100644
--- a/src/main.go
+++ b/src/main.go
@@ -2,13 +2,13 @@ package main
 
 import (
     "fmt"
-    . "./core"
-    . "./accelerator"
-    . "./bsdf"
-    . "./shape"
-    . "./sensor"
-    . "./sampler"
-    . "./integrator"
+    . "core"
+    . "accelerator"
+    . "bsdf"
+    . "shape"
+    . "sensor"
+    . "sampler"
+    . "integrator"
 )
 
 const (
diff --git a/src/sampler/independent.go b/src/sampler/independent.go
index eefaacd..9eb3d23 100644
--- a/src/sampler/independent.go
+++ b/src/sampler/independent.go
@@ -2,7 +2,7 @@ package sampler
 
 import (
     "math/rand"
-    . "../core"
+    . "core"
 )
 
 type IndependentSampler struct {
diff --git a/src/sensor/perspective.go b/src/sensor/perspective.go
index 6243e7c..6fee14f 100644
--- a/src/sensor/perspective.go
+++ b/src/sensor/perspective.go
@@ -2,7 +2,7 @@ package sensor
 
 import (
     "math"
-    . "../core"
+    . "core"
 )
 
 type PerspectiveSensor struct {
diff --git a/src/shape/sphere.go b/src/shape/sphere.go
index 240605d..9419bac 100644
--- a/src/shape/sphere.go
+++ b/src/shape/sphere.go
@@ -1,7 +1,7 @@
 package shape
 
 import (
-    . "../core"
+    . "core"
 )
 
 type Sphere struct {
diff --git a/src/shape/triangle.go b/src/shape/triangle.go
index c14b593..7489f96 100644
--- a/src/shape/triangle.go
+++ b/src/shape/triangle.go
@@ -2,7 +2,7 @@ package shape
 
 import (
     "math"
-    . "../core"
+    . "core"
 )
 
 type Triangle struct {
diff --git a/src/shape/triangle_test.go b/src/shape/triangle_test.go
index 52ec12e..34bbca3 100644
--- a/src/shape/triangle_test.go
+++ b/src/shape/triangle_test.go
@@ -2,7 +2,7 @@ package shape
 
 import (
     "testing"
-    . "../core"
+    . "core"
 )
 
 func TestTriangleIntersect(t *testing.T) {
diff --git a/src/shape/trimesh.go b/src/shape/trimesh.go
index c6cd8fd..358f802 100644
--- a/src/shape/trimesh.go
+++ b/src/shape/trimesh.go
@@ -7,7 +7,7 @@ import (
     "bufio"
     "strings"
     "strconv"
-    . "../core"
+    . "core"
 )
 
 type TriMesh struct {