diff --git a/.github/workflows/test-examples.yml b/.github/workflows/test-examples.yml
index 12e8551..d44ef73 100644
--- a/.github/workflows/test-examples.yml
+++ b/.github/workflows/test-examples.yml
@@ -11,7 +11,7 @@ jobs:
   test:
     strategy:
       matrix:
-        go-version: [1.18.x ]
+        go-version: [1.19.x ]
     runs-on: ubuntu-latest
     steps:
       - name: Install Go stable
diff --git a/_examples/advanced-generic/_testdata/openapi.json b/_examples/advanced-generic/_testdata/openapi.json
index 3a15b91..2541daf 100644
--- a/_examples/advanced-generic/_testdata/openapi.json
+++ b/_examples/advanced-generic/_testdata/openapi.json
@@ -318,7 +318,7 @@
                 "schema":{"type":"string","description":"Sample response header."}
               }
             },
-            "content":{"text/csv":{"schema":{}}}
+            "content":{"text/csv":{"schema":{"type":"string"}}}
           },
           "500":{
             "description":"Internal Server Error",
diff --git a/_examples/advanced-generic/router_test.go b/_examples/advanced-generic/router_test.go
index 55ae603..a581145 100644
--- a/_examples/advanced-generic/router_test.go
+++ b/_examples/advanced-generic/router_test.go
@@ -4,9 +4,9 @@ package main
 
 import (
 	"encoding/json"
-	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
+	"os"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -28,10 +28,10 @@ func TestNewRouter(t *testing.T) {
 	actualSchema, err := assertjson.MarshalIndentCompact(json.RawMessage(rw.Body.Bytes()), "", "  ", 120)
 	require.NoError(t, err)
 
-	expectedSchema, err := ioutil.ReadFile("_testdata/openapi.json")
+	expectedSchema, err := os.ReadFile("_testdata/openapi.json")
 	require.NoError(t, err)
 
 	if !assertjson.Equal(t, expectedSchema, rw.Body.Bytes(), string(actualSchema)) {
-		require.NoError(t, ioutil.WriteFile("_testdata/openapi_last_run.json", actualSchema, 0o600))
+		require.NoError(t, os.WriteFile("_testdata/openapi_last_run.json", actualSchema, 0o600))
 	}
 }
diff --git a/_examples/advanced/_testdata/openapi.json b/_examples/advanced/_testdata/openapi.json
index 2d5222d..942285a 100644
--- a/_examples/advanced/_testdata/openapi.json
+++ b/_examples/advanced/_testdata/openapi.json
@@ -286,7 +286,7 @@
                 "schema":{"type":"string","description":"Sample response header."}
               }
             },
-            "content":{"text/csv":{"schema":{}}}
+            "content":{"text/csv":{"schema":{"type":"string"}}}
           },
           "500":{
             "description":"Internal Server Error",
diff --git a/_examples/advanced/router_test.go b/_examples/advanced/router_test.go
index 94c334f..339ce34 100644
--- a/_examples/advanced/router_test.go
+++ b/_examples/advanced/router_test.go
@@ -2,9 +2,9 @@ package main
 
 import (
 	"encoding/json"
-	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
+	"os"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -26,10 +26,10 @@ func TestNewRouter(t *testing.T) {
 	actualSchema, err := assertjson.MarshalIndentCompact(json.RawMessage(rw.Body.Bytes()), "", "  ", 120)
 	require.NoError(t, err)
 
-	expectedSchema, err := ioutil.ReadFile("_testdata/openapi.json")
+	expectedSchema, err := os.ReadFile("_testdata/openapi.json")
 	require.NoError(t, err)
 
 	if !assertjson.Equal(t, expectedSchema, rw.Body.Bytes(), string(actualSchema)) {
-		require.NoError(t, ioutil.WriteFile("_testdata/openapi_last_run.json", actualSchema, 0o600))
+		require.NoError(t, os.WriteFile("_testdata/openapi_last_run.json", actualSchema, 0o600))
 	}
 }
diff --git a/openapi/collector_test.go b/openapi/collector_test.go
index ae38929..7d5ff3b 100644
--- a/openapi/collector_test.go
+++ b/openapi/collector_test.go
@@ -164,7 +164,7 @@ func TestCollector_Collect_requestMapping(t *testing.T) {
 			  },
 			  {
 				"name":"in_cookie","in":"cookie",
-				"schema":{"type":"string","format":"date-time"}
+				"schema":{"type":"string","format":"date-time","nullable":true}
 			  },
 			  {
 				"name":"X-In-Header","in":"header",
@@ -193,7 +193,7 @@ func TestCollector_Collect_requestMapping(t *testing.T) {
 			  },
 			  {
 				"name":"in_cookie","in":"cookie",
-				"schema":{"type":"string","format":"date-time"}
+				"schema":{"type":"string","format":"date-time","nullable":true}
 			  },
 			  {
 				"name":"X-In-Header","in":"header",