reproduce issue getkin#436

Signed-off-by: Pierre Fenoll <pierrefenoll@gmail.com>

openapi3filter/issue436_test.go

@@ -0,0 +1,105 @@
+package openapi3filter
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+	"mime/multipart"
+	"net/http"
+	"net/textproto"
+	"strings"
+	"testing"
+
+	"github.com/getkin/kin-openapi/openapi3"
+	"github.com/getkin/kin-openapi/routers/gorillamux"
+	"github.com/stretchr/testify/require"
+)
+
+func TestIssue436(t *testing.T) {
+	const testSchema = `
+openapi: 3.0.0
+info:
+  title: 'Validator'
+  version: 0.0.1
+paths:
+  /test:
+    post:
+      requestBody:
+        required: true
+        content:
+          multipart/form-data:
+          #application/json:
+            schema:
+              type: object
+              required:
+                - file
+              properties:
+                file:
+                  type: string
+                  format: binary
+                categories:
+                  type: array
+                  items:
+                    $ref: "#/components/schemas/Category"
+      responses:
+        '200':
+          description: Created
+
+components:
+  schemas:
+    Category:
+      type: object
+      properties:
+        name:
+          type: string
+      required:
+        - name
+`
+
+	doc, err := openapi3.NewLoader().LoadFromData([]byte(testSchema))
+	require.NoError(t, err)
+	err = doc.Validate(context.Background())
+	require.NoError(t, err)
+
+	router, err := gorillamux.NewRouter(doc)
+	require.NoError(t, err)
+
+	body := &bytes.Buffer{}
+	writer := multipart.NewWriter(body)
+
+	h := make(textproto.MIMEHeader)
+	h.Set("Content-Disposition", fmt.Sprintf(`form-data; name="%s"`, "categories"))
+	h.Set("Content-Type", "application/json")
+	fw, err := writer.CreatePart(h)
+	require.NoError(t, err)
+	_, err = io.Copy(fw, strings.NewReader(`[{"name": "foo"}]`))
+	require.NoError(t, err)
+
+	fw, err = writer.CreateFormFile("file", "hello.txt")
+	require.NoError(t, err)
+	_, err = io.Copy(fw, strings.NewReader("hello"))
+	require.NoError(t, err)
+
+	writer.Close()
+
+	req, _ := http.NewRequest(http.MethodPost, "/test", bytes.NewReader(body.Bytes()))
+	req.Header.Set("Content-Type", writer.FormDataContentType())
+
+	route, pathParams, _ := router.FindRoute(req)
+
+	reqBody := route.Operation.RequestBody.Value
+
+	requestValidationInput := &RequestValidationInput{
+		Request:    req,
+		PathParams: pathParams,
+		Route:      route,
+	}
+
+	err = ValidateRequestBody(context.TODO(), requestValidationInput, reqBody)
+	if err == nil {
+		fmt.Println("Valid")
+	} else {
+		fmt.Printf("NOT valid. %s\n", err)
+	}
+}