Remove testutil dependency

As it leads to a circular dependency when we want to consume this
middleware module from `oapi-codegen` itself, and as it's not doing too
much heavy lifting we can remove it.

go.mod

@@ -3,7 +3,6 @@ module github.com/oapi-codegen/echo-middleware
 go 1.20
 
 require (
-	github.com/deepmap/oapi-codegen v1.14.0
 	github.com/getkin/kin-openapi v0.118.0
 	github.com/labstack/echo/v4 v4.11.1
 	github.com/stretchr/testify v1.8.4
@@ -24,6 +23,7 @@ require (
 	github.com/mohae/deepcopy v0.0.0-20170929034955-c48cc78d4826 // indirect
 	github.com/perimeterx/marshmallow v1.1.4 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/ugorji/go/codec v1.2.11 // indirect
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
 	github.com/valyala/fasttemplate v1.2.2 // indirect
 	golang.org/x/crypto v0.12.0 // indirect

go.sum

@@ -2,8 +2,6 @@ github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ3
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 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/deepmap/oapi-codegen v1.14.0 h1:b51/kQwH69rjN5pu+8j/Q5fUGD/rUclLAcGLQWQwa3E=
-github.com/deepmap/oapi-codegen v1.14.0/go.mod h1:QcEpzjVDwJEH3Fq6I7XYkI0M/JwvoL82ToYveaeVMAw=
 github.com/getkin/kin-openapi v0.118.0 h1:z43njxPmJ7TaPpMSCQb7PN0dEYno4tyBPQcrFdHoLuM=
 github.com/getkin/kin-openapi v0.118.0/go.mod h1:l5e9PaFUo9fyLJCPGQeXI2ML8c3P8BHOEV2VaAVf/pc=
 github.com/go-openapi/jsonpointer v0.19.5/go.mod h1:Pl9vOtqEWErmShwVjC8pYs9cog34VGT37dQOVbmoatg=
@@ -62,10 +60,10 @@ github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO
 github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
-github.com/ugorji/go v1.2.7 h1:qYhyWUUd6WbiM+C6JZAUkIJt/1WrjzNHY9+KCIjVqTo=
 github.com/ugorji/go v1.2.7/go.mod h1:nF9osbDWLy6bDVv/Rtoh6QgnvNDpmCalQV5urGCCS6M=
 github.com/ugorji/go/codec v1.2.7/go.mod h1:WGN1fab3R1fzQlVQTkfxVtIBhWDRqOviHU95kRgeqEY=
 github.com/ugorji/go/codec v1.2.11 h1:BMaWp1Bb6fHwEtbplGBGJ498wD+LKlNSl25MjdZY4dU=
+github.com/ugorji/go/codec v1.2.11/go.mod h1:UNopzCgEMSXjBc6AOMqYvWC1ktqTAfzJZUZgYf6w6lg=
 github.com/valyala/bytebufferpool v1.0.0 h1:GqA5TC/0021Y/b9FG4Oi9Mr3q7XYx6KllzawFIhcdPw=
 github.com/valyala/bytebufferpool v1.0.0/go.mod h1:6bBcMArwyJ5K/AmCkWv1jt77kVWyCJ6HpOuEn7z0Csc=
 github.com/valyala/fasttemplate v1.2.1/go.mod h1:KHLXt3tVN2HBp8eijSv/kGJopbvo7S+qRAEEKiv+SiQ=

oapi_validate_test.go

@@ -15,16 +15,17 @@
 package echomiddleware
 
 import (
+	"bytes"
 	"context"
 	_ "embed"
+	"encoding/json"
 	"errors"
 	"io"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
 	"testing"
 
-	"github.com/deepmap/oapi-codegen/pkg/testutil"
 	"github.com/getkin/kin-openapi/openapi3"
 	"github.com/getkin/kin-openapi/openapi3filter"
 	"github.com/labstack/echo/v4"
@@ -42,8 +43,18 @@ func doGet(t *testing.T, e *echo.Echo, rawURL string) *httptest.ResponseRecorder
 		t.Fatalf("Invalid url: %s", rawURL)
 	}
 
-	response := testutil.NewRequest().Get(u.RequestURI()).WithHost(u.Host).WithAcceptJson().GoWithHTTPHandler(t, e)
-	return response.Recorder
+	r, err := http.NewRequest(http.MethodGet, u.String(), nil)
+	if err != nil {
+		t.Fatalf("Could not construct a request: %s", rawURL)
+	}
+	r.Header.Set("accept", "application/json")
+	r.Header.Set("host", u.Host)
+
+	tt := httptest.NewRecorder()
+
+	e.ServeHTTP(tt, r)
+
+	return tt
 }
 
 func doPost(t *testing.T, e *echo.Echo, rawURL string, jsonBody interface{}) *httptest.ResponseRecorder {
@@ -52,8 +63,24 @@ func doPost(t *testing.T, e *echo.Echo, rawURL string, jsonBody interface{}) *ht
 		t.Fatalf("Invalid url: %s", rawURL)
 	}
 
-	response := testutil.NewRequest().Post(u.RequestURI()).WithHost(u.Host).WithJsonBody(jsonBody).GoWithHTTPHandler(t, e)
-	return response.Recorder
+	body, err := json.Marshal(jsonBody)
+	if err != nil {
+		t.Fatalf("Could not marshal request body: %v", err)
+	}
+
+	r, err := http.NewRequest(http.MethodPost, u.String(), bytes.NewReader(body))
+	if err != nil {
+		t.Fatalf("Could not construct a request for URL %s: %v", rawURL, err)
+	}
+	r.Header.Set("accept", "application/json")
+	r.Header.Set("content-type", "application/json")
+	r.Header.Set("host", u.Host)
+
+	tt := httptest.NewRecorder()
+
+	e.ServeHTTP(tt, r)
+
+	return tt
 }
 
 func TestOapiRequestValidator(t *testing.T) {