From d02b7391f00946e0390ae5c3d684dd343f30a49b Mon Sep 17 00:00:00 2001
From: Miladev95 <miladev95@gmail.com>
Date: Tue, 23 Dec 2025 16:09:33 +0330
Subject: [PATCH] add plain binding tests

---
 binding/plain_test.go | 93 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)
 create mode 100644 binding/plain_test.go

diff --git a/binding/plain_test.go b/binding/plain_test.go
new file mode 100644
index 00000000..846fdd76
--- /dev/null
+++ b/binding/plain_test.go
@@ -0,0 +1,93 @@
+// Copyright 2025 Gin Core Team. All rights reserved.
+// Use of this source code is governed by a MIT style
+// license that can be found in the LICENSE file.
+
+package binding
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"net/http"
+	"strings"
+	"testing"
+)
+
+// errReadCloser simulates a ReadCloser whose Read returns a fixed error.
+type errReadCloser struct{ err error }
+
+func (e *errReadCloser) Read(p []byte) (int, error) { return 0, e.err }
+func (e *errReadCloser) Close() error               { return nil }
+
+func TestDecodePlain_String_Success(t *testing.T) {
+	t.Parallel()
+	var s string
+	if err := (plainBinding{}).BindBody([]byte("hello world"), &s); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if s != "hello world" {
+		t.Fatalf("expected %q, got %q", "hello world", s)
+	}
+}
+
+func TestDecodePlain_ByteSlice_Success(t *testing.T) {
+	t.Parallel()
+	in := []byte{1, 2, 3, 4}
+	var b []byte
+	if err := (plainBinding{}).BindBody(in, &b); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if !bytes.Equal(b, in) {
+		t.Fatalf("expected %v, got %v", in, b)
+	}
+}
+
+func TestPlainBind_UsesHTTPRequestBody(t *testing.T) {
+	t.Parallel()
+	var s string
+	req := &http.Request{Body: io.NopCloser(bytes.NewReader([]byte("reqbody")))}
+	if err := (plainBinding{}).Bind(req, &s); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if s != "reqbody" {
+		t.Fatalf("expected %q, got %q", "reqbody", s)
+	}
+}
+
+func TestDecodePlain_NilObj_NoPanic(t *testing.T) {
+	// Passing nil obj should be a no-op and return nil error.
+	if err := (plainBinding{}).BindBody([]byte("x"), nil); err != nil {
+		t.Fatalf("expected nil error for nil obj, got %v", err)
+	}
+
+	// Passing a nil pointer (e.g., *string == nil) should also return nil error.
+	var ps *string = nil
+	if err := (plainBinding{}).BindBody([]byte("x"), ps); err != nil {
+		t.Fatalf("expected nil error for nil pointer obj, got %v", err)
+	}
+}
+
+func TestDecodePlain_UnsupportedType_Error(t *testing.T) {
+	var x int
+	err := (plainBinding{}).BindBody([]byte("x"), &x)
+	if err == nil {
+		t.Fatalf("expected error for unsupported type, got nil")
+	}
+	if !strings.Contains(err.Error(), "unknown type") {
+		t.Fatalf("expected error to contain 'unknown type', got %v", err)
+	}
+}
+
+func TestPlainBind_ReadError(t *testing.T) {
+	t.Parallel()
+	sentinel := errors.New("read fail")
+	req := &http.Request{Body: &errReadCloser{err: sentinel}}
+	var s string
+	err := (plainBinding{}).Bind(req, &s)
+	if err == nil {
+		t.Fatalf("expected read error, got nil")
+	}
+	if err != sentinel {
+		t.Fatalf("expected sentinel error %v, got %v", sentinel, err)
+	}
+}