[structs] change package structutil to structs (#81)

* refactor package structutil to structs

* add structs package zh-CN docs

structs/struct_test.go

@@ -0,0 +1,132 @@
+package structs
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/duke-git/lancet/v2/internal"
+)
+
+func TestStruct_ToMap(t *testing.T) {
+	assert := internal.NewAssert(t, "TestStruct_ToMap")
+
+	t.Run("invalid struct", func(t *testing.T) {
+		m, _ := ToMap(1)
+		var expected map[string]any
+		assert.Equal(expected, m)
+	})
+
+	t.Run("StructToMap", func(_ *testing.T) {
+		type People struct {
+			Name string `json:"name"`
+			age  int
+		}
+		p := &People{
+			"test",
+			100,
+		}
+		pm, _ := ToMap(p)
+		var expected = map[string]any{"name": "test"}
+		assert.Equal(expected, pm)
+	})
+
+	t.Run("StructToMapWithJsonAttr", func(_ *testing.T) {
+		type People struct {
+			Name      string `json:"name,omitempty"` // json tag with attribute
+			Phone     string `json:"phone"`          // json tag without attribute
+			Sex       string `json:"-"`              // ignore by "-"
+			Age       int    // ignore by no tag
+			email     string // ignore by unexported
+			IsWorking bool   `json:"is_working"`
+		}
+		p1 := People{
+			Name:  "AAA", // exist
+			Phone: "1111",
+			Sex:   "male",
+			Age:   100,
+			email: "11@gmail.com",
+		}
+		p1m, _ := ToMap(p1)
+		var expect1 = map[string]any{"name": "AAA", "phone": "1111", "is_working": false}
+		assert.Equal(expect1, p1m)
+
+		p2 := People{
+			Name:      "",
+			Phone:     "2222",
+			Sex:       "male",
+			Age:       0,
+			email:     "22@gmail.com",
+			IsWorking: true,
+		}
+		p2m, _ := ToMap(p2)
+		var expect2 = map[string]any{"phone": "2222", "is_working": true}
+		assert.Equal(expect2, p2m)
+	})
+}
+
+func TestStruct_Fields(t *testing.T) {
+	assert := internal.NewAssert(t, "TestStruct_Fields")
+
+	type Parent struct {
+		A string         `json:"a"`
+		B int            `json:"b"`
+		C []string       `json:"c"`
+		D map[string]any `json:"d"`
+	}
+
+	p1 := &Parent{
+		A: "1",
+		B: 11,
+		C: []string{"11", "22"},
+		D: map[string]any{"d1": 1, "d2": 2},
+	}
+
+	s := New(p1)
+	fields := s.Fields()
+	assert.Equal(4, len(fields))
+	assert.Equal(reflect.String, fields[0].Kind())
+	assert.Equal(reflect.Int, fields[1].Kind())
+	assert.Equal(reflect.Slice, fields[2].Kind())
+	assert.Equal(reflect.Map, fields[3].Kind())
+}
+
+func TestStruct_Field(t *testing.T) {
+	assert := internal.NewAssert(t, "TestStruct_Field")
+
+	type Parent struct {
+		A string         `json:"a"`
+		B int            `json:"b"`
+		C []string       `json:"c"`
+		D map[string]any `json:"d"`
+	}
+
+	p1 := &Parent{
+		A: "1",
+		B: 11,
+		C: []string{"11", "22"},
+		D: map[string]any{"d1": 1, "d2": 2},
+	}
+
+	s := New(p1)
+	a, ok := s.Field("A")
+	assert.Equal(true, ok)
+	assert.Equal(reflect.String, a.Kind())
+	assert.Equal("1", a.Value())
+	assert.Equal("a", a.tag.Name)
+	assert.Equal(false, a.tag.HasOption("omitempty"))
+	assert.Equal(false, a.tag.IsEmpty())
+}
+
+func TestStruct_IsStruct(t *testing.T) {
+	assert := internal.NewAssert(t, "TestStruct_Field")
+
+	type Test1 struct{}
+	t1 := &Test1{}
+	t2 := 1
+
+	s1 := New(t1)
+	s2 := New(t2)
+
+	assert.Equal(true, s1.IsStruct())
+	assert.Equal(false, s2.IsStruct())
+}