diff --git a/internal/config/config.go b/internal/config/config.go
index 5f6a854..efb90ad 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -91,14 +91,13 @@ func Parse(path string) (Config, error) {
 	if err != nil {
 		return Config{}, fmt.Errorf("build dag: %w", err)
 	}
-	graph.Resolve()
-	cfg := graph.cfg
+	cfg := graph.Resolve()
 
 	if err = cfg.validate(); err != nil {
 		return Config{}, fmt.Errorf("validate config: %w", err)
 	}
 
-	return *cfg, nil
+	return cfg, nil
 }
 
 // Decode decodes from a slice of bytes to a [Config] structure.
diff --git a/internal/config/configgraph.go b/internal/config/configgraph.go
index 1d086fb..e2c6666 100644
--- a/internal/config/configgraph.go
+++ b/internal/config/configgraph.go
@@ -7,9 +7,6 @@ import (
 	"fmt"
 	"io"
 	"log/slog"
-	"os"
-
-	hdag "github.com/heimdalr/dag"
 
 	"github.com/adevinta/lava/internal/config/dag"
 	"github.com/adevinta/lava/internal/urlutil"
@@ -19,7 +16,6 @@ import (
 type ConfigGraph struct {
 	dag     *dag.DAG
 	configs map[string]Config
-	cfg     *Config
 }
 
 // NewConfigGraph creates a new [ConfigGraph] that represents the whole configuration.
@@ -88,25 +84,25 @@ func (cg *ConfigGraph) Config(url string) (Config, error) {
 	return Config{}, fmt.Errorf("could not find config for %s", url)
 }
 
-// Visit executes the merge when a vertex is visited.
-func (cg *ConfigGraph) Visit(v hdag.Vertexer) {
-	_, cfg := v.Vertex()
-	config, err := cg.Config(cfg.(string))
-	if err != nil {
-		os.Exit(1)
-	}
-	if cg.cfg == nil {
-		cg.cfg = &config
-	} else {
-		mergedConfig, err := merge(config, *cg.cfg)
+// Resolve walks the dag and merge the configuration.
+func (cg *ConfigGraph) Resolve() Config {
+	var cfg *Config
+	cg.dag.DFSWalk(func(vertexID string, vertex interface{}) {
+		vexCfg, err := cg.Config(vertex.(string))
 		if err != nil {
-			os.Exit(1)
+			panic(err)
 		}
-		cg.cfg = &mergedConfig
-	}
-}
 
-// Resolve walks the dag and merge the configuration.
-func (cg *ConfigGraph) Resolve() {
-	cg.dag.Dag.DFSWalk(cg)
+		if cfg == nil {
+			cfg = &vexCfg
+			return
+		}
+
+		vexCfg, err = merge(vexCfg, *cfg)
+		if err != nil {
+			panic(err)
+		}
+		cfg = &vexCfg
+	})
+	return *cfg
 }
diff --git a/internal/config/configgraph_test.go b/internal/config/configgraph_test.go
index d13e4b6..6f04507 100644
--- a/internal/config/configgraph_test.go
+++ b/internal/config/configgraph_test.go
@@ -27,7 +27,7 @@ func TestNewConfigGraph(t *testing.T) {
 					"testdata/include/no_includes.yaml": {
 						LavaVersion: ptr("v1.0.0"),
 						ChecktypeURLs: []string{
-							"commonchecktypes.json",
+							"checktypes_no_includes.json",
 						},
 						Targets: []Target{
 							{
@@ -61,7 +61,7 @@ func TestNewConfigGraph(t *testing.T) {
 					"testdata/include/no_includes.yaml": {
 						LavaVersion: ptr("v1.0.0"),
 						ChecktypeURLs: []string{
-							"commonchecktypes.json",
+							"checktypes_no_includes.json",
 						},
 						Targets: []Target{
 							{
@@ -103,7 +103,7 @@ func TestNewConfigGraph(t *testing.T) {
 					"testdata/include/no_includes.yaml": {
 						LavaVersion: ptr("v1.0.0"),
 						ChecktypeURLs: []string{
-							"commonchecktypes.json",
+							"checktypes_no_includes.json",
 						},
 						Targets: []Target{
 							{
@@ -172,7 +172,7 @@ func TestNewConfigGraph(t *testing.T) {
 					"testdata/include/no_includes.yaml": {
 						LavaVersion: ptr("v1.0.0"),
 						ChecktypeURLs: []string{
-							"commonchecktypes.json",
+							"checktypes_no_includes.json",
 						},
 						Targets: []Target{
 							{
@@ -216,7 +216,7 @@ func TestConfigGraph_Resolve(t *testing.T) {
 			want: Config{
 				LavaVersion: ptr("v1.0.0"),
 				ChecktypeURLs: []string{
-					"commonchecktypes.json",
+					"checktypes_no_includes.json",
 				},
 				Targets: []Target{
 					{
@@ -234,7 +234,7 @@ func TestConfigGraph_Resolve(t *testing.T) {
 				Includes:    []string{"testdata/include/no_includes.yaml"},
 				LavaVersion: ptr("v1.0.0"),
 				ChecktypeURLs: []string{
-					"commonchecktypes.json",
+					"checktypes_no_includes.json",
 					"checktypes.json",
 				},
 				Targets: []Target{
@@ -260,7 +260,7 @@ func TestConfigGraph_Resolve(t *testing.T) {
 				},
 				LavaVersion: ptr("v1.0.0"),
 				ChecktypeURLs: []string{
-					"commonchecktypes.json",
+					"checktypes_no_includes.json",
 					"checktypes.json",
 				},
 				Targets: []Target{
@@ -289,7 +289,7 @@ func TestConfigGraph_Resolve(t *testing.T) {
 				LavaVersion: ptr("v1.0.0"),
 				ChecktypeURLs: []string{
 					"checktypes.json",
-					"commonchecktypes.json",
+					"checktypes_no_includes.json",
 					"checktypes.json",
 					"checktypes.json",
 				},
@@ -324,12 +324,11 @@ func TestConfigGraph_Resolve(t *testing.T) {
 			if err != nil {
 				t.Errorf("build dag: %v", err)
 			}
-			graph.Resolve()
-			got := graph.cfg
+			got := graph.Resolve()
 			if (err != nil) != tt.wantErr {
-				t.Errorf("unexpected error: want: %v, got: %v", tt.wantErr, err)
+				t.Errorf("unexpected error: %v", err)
 			}
-			if diff := cmp.Diff(tt.want, *got); diff != "" {
+			if diff := cmp.Diff(tt.want, got); diff != "" {
 				t.Errorf("configs mismatch (-want +got):\n%v", diff)
 			}
 		})
diff --git a/internal/config/dag/dag.go b/internal/config/dag/dag.go
index 48b11e6..b90e5bd 100644
--- a/internal/config/dag/dag.go
+++ b/internal/config/dag/dag.go
@@ -29,14 +29,14 @@ var (
 
 // DAG represents a Direct Acyclic Graph object.
 type DAG struct {
-	Dag      *hdag.DAG
+	dag      *hdag.DAG
 	vertices map[string]string
 }
 
 // New returns a Directed Acyclic Graph object.
 func New() *DAG {
 	return &DAG{
-		Dag:      hdag.NewDAG(),
+		dag:      hdag.NewDAG(),
 		vertices: make(map[string]string),
 	}
 }
@@ -44,7 +44,7 @@ func New() *DAG {
 // AddVertex adds the vertex x to the DAG. AddVertex returns an error if s is
 // nil or s is already part of the graph.
 func (d *DAG) AddVertex(s string) (string, error) {
-	id, err := d.Dag.AddVertex(s)
+	id, err := d.dag.AddVertex(s)
 	if err != nil {
 		if errors.As(err, &hdag.VertexDuplicateError{}) {
 			return id, fmt.Errorf("%w: %s", ErrDuplicatedVertex, s)
@@ -66,7 +66,7 @@ func (d *DAG) AddEdge(from, to string) error {
 	if toID == "" {
 		return fmt.Errorf("%w: %s", ErrUnknownVertex, to)
 	}
-	err := d.Dag.AddEdge(fromID, toID)
+	err := d.dag.AddEdge(fromID, toID)
 	if err != nil {
 		if errors.As(err, &hdag.EdgeDuplicateError{}) {
 			return fmt.Errorf("%w: from %s to %s", ErrDuplicatedEdge, from, to)
@@ -94,3 +94,13 @@ func (d *DAG) getVertexID(s string) string {
 	}
 	return ""
 }
+
+type WalkFunc func(vertexID string, vertex interface{})
+
+func (fn WalkFunc) Visit(v hdag.Vertexer) {
+	fn(v.Vertex())
+}
+
+func (d *DAG) DFSWalk(fn WalkFunc) {
+	d.dag.DFSWalk(fn)
+}
diff --git a/internal/config/testdata/include/common.yaml b/internal/config/testdata/include/common.yaml
index 9374887..b4dd278 100644
--- a/internal/config/testdata/include/common.yaml
+++ b/internal/config/testdata/include/common.yaml
@@ -8,4 +8,4 @@ targets:
   - identifier: example.com
     type: DomainName
 report:
-  severity: critical
\ No newline at end of file
+  severity: critical
diff --git a/internal/config/testdata/include/common_a.yaml b/internal/config/testdata/include/common_a.yaml
index 38d1f1f..30cefd2 100644
--- a/internal/config/testdata/include/common_a.yaml
+++ b/internal/config/testdata/include/common_a.yaml
@@ -7,4 +7,4 @@ targets:
   - identifier: example.com
     type: DomainName
 report:
-  severity: medium
\ No newline at end of file
+  severity: medium
diff --git a/internal/config/testdata/include/no_includes.yaml b/internal/config/testdata/include/no_includes.yaml
index 2c36635..ec00775 100644
--- a/internal/config/testdata/include/no_includes.yaml
+++ b/internal/config/testdata/include/no_includes.yaml
@@ -1,6 +1,6 @@
 lava: v1.0.0
 checktypes:
-  - commonchecktypes.json
+  - checktypes_no_includes.json
 targets:
   - identifier: example.com
     type: DomainName