diff --git a/pkg/dockerfile/client_test.go b/pkg/dockerfile/client_test.go
new file mode 100644
index 00000000..d7e6ae15
--- /dev/null
+++ b/pkg/dockerfile/client_test.go
@@ -0,0 +1,74 @@
+package dockerfile_test
+
+import (
+	"fmt"
+	"os"
+	"testing"
+
+	"github.com/crazy-max/diun/v4/pkg/dockerfile"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+var (
+	dc *dockerfile.Client
+)
+
+func TestMain(m *testing.M) {
+	var err error
+
+	dc, err = dockerfile.New(dockerfile.Options{
+		Filename: "./fixtures/valid.Dockerfile",
+	})
+	if err != nil {
+		panic(err.Error())
+	}
+
+	os.Exit(m.Run())
+}
+
+func TestNew(t *testing.T) {
+	assert.NotNil(t, dc)
+}
+
+func TestLoadFile(t *testing.T) {
+	cases := []struct {
+		name    string
+		dfile   string
+		wantErr bool
+	}{
+		{
+			name:    "Failed on non-existing file",
+			dfile:   "",
+			wantErr: true,
+		},
+		{
+			name:    "Fail on empty file",
+			dfile:   "./fixtures/empty.Dockerfile",
+			wantErr: true,
+		},
+		{
+			name:    "Fail on wrong file format",
+			dfile:   "./fixtures/invalid.Dockerfile",
+			wantErr: true,
+		},
+		{
+			name:    "Valid",
+			dfile:   "./fixtures/valid.Dockerfile",
+			wantErr: false,
+		},
+	}
+	for _, tt := range cases {
+		t.Run(tt.name, func(t *testing.T) {
+			c, err := dockerfile.New(dockerfile.Options{
+				Filename: tt.dfile,
+			})
+			if tt.wantErr {
+				fmt.Println(err)
+				require.Error(t, err)
+				return
+			}
+			assert.NotNil(t, c)
+		})
+	}
+}
diff --git a/pkg/dockerfile/fixtures/empty.Dockerfile b/pkg/dockerfile/fixtures/empty.Dockerfile
new file mode 100644
index 00000000..e69de29b
diff --git a/pkg/dockerfile/fixtures/invalid.Dockerfile b/pkg/dockerfile/fixtures/invalid.Dockerfile
new file mode 100644
index 00000000..7f173134
--- /dev/null
+++ b/pkg/dockerfile/fixtures/invalid.Dockerfile
@@ -0,0 +1 @@
+invalid dockerfile
diff --git a/pkg/dockerfile/fixtures/valid.Dockerfile b/pkg/dockerfile/fixtures/valid.Dockerfile
new file mode 100644
index 00000000..a295b329
--- /dev/null
+++ b/pkg/dockerfile/fixtures/valid.Dockerfile
@@ -0,0 +1,17 @@
+# syntax=docker/dockerfile:1.3
+ARG ALPINE_VERSION=3.14
+
+# diun.platform=linux/amd64
+FROM alpine:${ALPINE_VERSION}
+
+# diun.watch_repo=true
+# diun.max_tags=10
+# diun.platform=linux/amd64
+COPY --from=crazymax/yasu / /
+
+# diun.watch_repo=true
+# diun.include_tags=^\d+\.\d+\.\d+$
+# diun.platform=linux/amd64
+RUN --mount=type=bind,target=.,rw \
+  --mount=type=bind,from=crazymax/docker:20.10.6,source=/usr/local/bin/docker,target=/usr/bin/docker \
+  yasu --version
diff --git a/pkg/dockerfile/image.go b/pkg/dockerfile/image.go
index a7ded6bf..fb177d6e 100644
--- a/pkg/dockerfile/image.go
+++ b/pkg/dockerfile/image.go
@@ -1,6 +1,8 @@
 package dockerfile
 
 import (
+	"strings"
+
 	"github.com/moby/buildkit/frontend/dockerfile/command"
 	"github.com/moby/buildkit/frontend/dockerfile/instructions"
 	"github.com/pkg/errors"
@@ -29,7 +31,7 @@ func (c *Client) FromImages() (Images, error) {
 	images := Images{}
 
 	for _, node := range c.ast.Children {
-		switch node.Value {
+		switch strings.ToLower(node.Value) {
 		case command.From:
 			ins, err := instructions.ParseInstruction(node)
 			if err != nil {
diff --git a/pkg/dockerfile/image_test.go b/pkg/dockerfile/image_test.go
new file mode 100644
index 00000000..a4d909fa
--- /dev/null
+++ b/pkg/dockerfile/image_test.go
@@ -0,0 +1,34 @@
+package dockerfile_test
+
+import (
+	"testing"
+
+	"github.com/crazy-max/diun/v4/pkg/dockerfile"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestFromImages(t *testing.T) {
+	c, err := dockerfile.New(dockerfile.Options{
+		Filename: "./fixtures/valid.Dockerfile",
+	})
+	require.NoError(t, err)
+	require.NotNil(t, c)
+
+	img, err := c.FromImages()
+	require.NoError(t, err)
+	require.NotNil(t, img)
+	require.Equal(t, 3, len(img))
+
+	assert.Equal(t, "alpine:3.14", img[0].Name)
+	assert.Equal(t, 5, img[0].Line)
+	assert.Equal(t, []string{"diun.platform=linux/amd64"}, img[0].Comments)
+
+	assert.Equal(t, "crazymax/yasu", img[1].Name)
+	assert.Equal(t, 10, img[1].Line)
+	assert.Equal(t, []string{"diun.watch_repo=true", "diun.max_tags=10", "diun.platform=linux/amd64"}, img[1].Comments)
+
+	assert.Equal(t, "crazymax/docker:20.10.6", img[2].Name)
+	assert.Equal(t, 15, img[2].Line)
+	assert.Equal(t, []string{"diun.watch_repo=true", "diun.include_tags=^\\d+\\.\\d+\\.\\d+$", "diun.platform=linux/amd64"}, img[2].Comments)
+}