From 8fa436ed1ac4200ff58b9f2c688c6e65dfac7500 Mon Sep 17 00:00:00 2001
From: "dedal.qq" <dedal.qq@gmail.com>
Date: Wed, 13 Oct 2021 16:51:36 +0300
Subject: [PATCH] first commit

---
 README.md               |  4 ++++
 go.mod                  |  3 +++
 setPrivateValue.go      | 45 +++++++++++++++++++++++++++++++++++++++++
 setPrivateValue_test.go | 18 +++++++++++++++++
 testmodule/omg.go       | 13 ++++++++++++
 5 files changed, 83 insertions(+)
 create mode 100644 README.md
 create mode 100644 go.mod
 create mode 100644 setPrivateValue.go
 create mode 100644 setPrivateValue_test.go
 create mode 100644 testmodule/omg.go

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..af3c1b2
--- /dev/null
+++ b/README.md
@@ -0,0 +1,4 @@
+# omg.testingTools
+
+---
+
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..e03836f
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module omg.testingtools
+
+go 1.17
diff --git a/setPrivateValue.go b/setPrivateValue.go
new file mode 100644
index 0000000..f73f17a
--- /dev/null
+++ b/setPrivateValue.go
@@ -0,0 +1,45 @@
+package testingtools
+
+import (
+	"fmt"
+	"reflect"
+	"unsafe"
+)
+
+func SetPrivateValue(obj interface{}, fieldName string, value interface{}) {
+	reflectValue := reflect.ValueOf(obj)
+
+	if reflectValue.Kind() != reflect.Ptr {
+		panic("object is not a pointer")
+	}
+
+	reflectValue = reflectValue.Elem()
+	reflectType := reflect.TypeOf(obj).Elem()
+
+	if reflectValue.Kind() != reflect.Struct {
+		panic("object is not a pointer to struct")
+	}
+
+	newReflectValueType := reflect.TypeOf(value)
+
+	var offset uintptr
+
+	for i := 0; i < reflectValue.NumField(); i++ {
+		if reflectType.Field(i).Name == fieldName {
+			currentFieldType := reflectType.Field(i).Type.String()
+
+			if newReflectValueType.String() != currentFieldType {
+				panic(fmt.Sprintf("incorrect type: must be %s", currentFieldType))
+			}
+
+			fieldPtr := unsafe.Pointer(reflectValue.UnsafeAddr() + offset)
+			reflect.NewAt(newReflectValueType, fieldPtr).Elem().Set(reflect.ValueOf(value))
+
+			return
+		}
+
+		offset += reflectValue.Field(i).Type().Size()
+	}
+
+	panic(fmt.Sprintf("Field [%s] not found in struct", fieldName))
+}
diff --git a/setPrivateValue_test.go b/setPrivateValue_test.go
new file mode 100644
index 0000000..d2078f5
--- /dev/null
+++ b/setPrivateValue_test.go
@@ -0,0 +1,18 @@
+package testingtools
+
+import (
+	"fmt"
+	"omg.testingtools/testmodule"
+	"testing"
+)
+
+func TestSetPrivateValue(t *testing.T) {
+	qq := testmodule.NewQQ(123, "abc", []int{5, 6, 7})
+
+	SetPrivateValue(&qq, "c", []int{1, 2, 3, 4})
+	SetPrivateValue(&qq, "b", "qwe")
+
+	if fmt.Sprint(qq) != "{123 qwe [1 2 3 4]}" {
+		t.Fail()
+	}
+}
diff --git a/testmodule/omg.go b/testmodule/omg.go
new file mode 100644
index 0000000..be4af55
--- /dev/null
+++ b/testmodule/omg.go
@@ -0,0 +1,13 @@
+package testmodule
+
+type TestStruct struct {
+	a int
+	b string
+	c []int
+}
+
+func NewQQ(a int, b string, c []int) TestStruct {
+	return TestStruct{
+		a, b, c,
+	}
+}