diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d6a5241..14cd079 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,8 +13,14 @@ permissions:
 jobs:
   # Test golangci-lint for go-version define in go.mod
   golangci:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     steps:
+      - name: Install harfbuzz
+        run: sudo apt-get install libharfbuzz-dev
+      - name: Set PKG_CONFIG_PATH
+        run: export PKG_CONFIG_PATH=/usr/include/harfbuzz
+      - name: Install GCC
+        run: sudo apt-get install gcc
       - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac #v4.0.0
       - uses: actions/setup-go@93397bea11091df50f3d7e59dc26a7711a8bcfbe #v4.1.0
         with:
@@ -25,3 +31,20 @@ jobs:
         with:
           version: latest
           only-new-issues: true
+
+  tests:
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Install harfbuzz
+        run: sudo apt-get install libharfbuzz-dev
+      - name: Set PKG_CONFIG_PATH
+        run: export PKG_CONFIG_PATH=/usr/include/harfbuzz
+      - name: Install GCC
+        run: sudo apt-get install gcc
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac #v4.0.0
+      - uses: actions/setup-go@93397bea11091df50f3d7e59dc26a7711a8bcfbe #v4.1.0
+        with:
+          go-version-file: go.mod
+          cache: false
+      - name: Test
+        run: go test -v ./...
diff --git a/font_test.go b/font_test.go
new file mode 100644
index 0000000..afad536
--- /dev/null
+++ b/font_test.go
@@ -0,0 +1,28 @@
+package writer
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFontSize(t *testing.T) {
+	face := &Face{} // Mock Face object
+	size := int32(12)
+
+	font := NewFont(face, size)
+	fontSize := font.Size()
+
+	assert.Equal(t, size, fontSize)
+}
+
+func TestSetFontReSize(t *testing.T) {
+	face := &Face{} // Mock Face object
+	size := int32(12)
+
+	font := NewFont(face, size)
+	newSize := int32(16)
+	font.SetSize(newSize)
+
+	assert.Equal(t, newSize, font.Size())
+}
diff --git a/go.mod b/go.mod
index d086d98..11abed2 100644
--- a/go.mod
+++ b/go.mod
@@ -1,12 +1,19 @@
 module github.com/haashemi/writer
 
-go 1.20.0
+go 1.20
 
 require (
 	github.com/haashemi/go-harfbuzz v0.0.0-20240304202021-7d8c8e99547f
 	github.com/mattn/go-pointer v0.0.1
+	github.com/stretchr/testify v1.9.0
 	golang.org/x/image v0.15.0
 	golang.org/x/text v0.14.0
 )
 
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)
+
 // replace github.com/haashemi/go-harfbuzz v0.0.1 => ../go-harfbuzz
diff --git a/go.sum b/go.sum
index 6a6b677..85d43b1 100644
--- a/go.sum
+++ b/go.sum
@@ -1,8 +1,18 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/haashemi/go-harfbuzz v0.0.0-20240304202021-7d8c8e99547f h1:3RpC5xQxtwaqG8D417EIiC23/RxOrk7g2efIz4DXZww=
 github.com/haashemi/go-harfbuzz v0.0.0-20240304202021-7d8c8e99547f/go.mod h1:x/7sZksqZHTio7OmfVgHo2K1GelkqAWcg4FAIBp4iqA=
 github.com/mattn/go-pointer v0.0.1 h1:n+XhsuGeVO6MEAp7xyEukFINEa+Quek5psIR/ylA6o0=
 github.com/mattn/go-pointer v0.0.1/go.mod h1:2zXcozF6qYGgmsG+SeTZz3oAbFLdD3OWqnUbNvJZAlc=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
+github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 golang.org/x/image v0.15.0 h1:kOELfmgrmJlw4Cdb7g/QGuB3CvDrXbqEIww/pNtNBm8=
 golang.org/x/image v0.15.0/go.mod h1:HUYqC05R2ZcZ3ejNQsIHQDQiwWM4JBqmm6MKANTp4LE=
 golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
 golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=