1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
|
package converter
import (
"fmt"
"reflect"
"testing"
)
func Test_ConverterChain(t *testing.T) {
chain := NewChain(V1{}, V2{}, V3{}, V4{})
tests := []struct {
name string
from interface{}
to interface{}
err string
}{
{
name: "from 1 to 2",
from: V1{
Name: "some-name",
Field1: "some-value",
},
to: V2{
Name: "some-name",
Field2: "some-value",
},
},
{
name: "from 1 to 3",
from: V1{
Field1: "some-value",
},
to: V3{
Field3: "some-value",
},
},
{
name: "from 2 to 4",
from: V2{
Name: "some-name",
Field2: "some-value",
},
to: V4{
Name: "some-name",
UpdatedField1: "some-value",
},
},
{
name: "from 4 to 1",
from: V4{
Name: "some-name",
UpdatedField1: "some-value",
},
to: V1{
Name: "some-name",
Field1: "some-value",
},
},
{
name: "from nil value",
from: (*V1)(nil),
to: V3{},
},
{
name: "invalid FROM type",
from: Invalid{},
to: V1{},
err: "invalid FROM type provided, not in the conversion chain: Invalid",
},
{
name: "invalid TO type",
from: V1{},
to: Invalid{},
err: "invalid TO type provided, not in the conversion chain: Invalid",
},
}
for _, test := range tests {
t.Run(test.name, func(t *testing.T) {
typ := reflect.TypeOf(test.to)
newInstance := reflect.New(typ)
result := newInstance.Interface()
err := chain.Convert(test.from, result)
if test.err != "" {
msg := fmt.Sprintf("%v", err)
if test.err != msg {
t.Fatalf("expected error '%s' but got: '%v'", test.err, msg)
}
return
} else if err != nil {
t.Fatalf("error during conversion: %v", err)
}
// need to align elem vs. pointer of the result
result = reflect.ValueOf(result).Elem().Interface()
to := test.to
if !reflect.DeepEqual(to, result) {
t.Fatalf("Convert output does not match: %+v %+v", to, result)
}
})
}
}
// a "version 1" struct
type V1 struct {
Name string
Field1 string
}
func (t *V1) ConvertFrom(from interface{}) error {
if c, ok := from.(V2); ok { // reverse migration
t.Field1 = c.Field2
}
return nil
}
// a "version 2" struct
type V2 struct {
Name string
Field2 string
}
func (t *V2) ConvertFrom(from interface{}) error {
if c, ok := from.(V1); ok { // forward migration
t.Field2 = c.Field1
}
if c, ok := from.(V3); ok { // reverse migration
t.Field2 = c.Field3
}
return nil
}
// a "version 3" struct
type V3 struct {
Name string
Field3 string
}
func (t *V3) ConvertFrom(from interface{}) error {
if c, ok := from.(V2); ok { // forward migration
t.Field3 = c.Field2
}
if c, ok := from.(V4); ok { // reverse migration
t.Field3 = c.UpdatedField1
}
return nil
}
// a "version 4" struct
type V4 struct {
Name string
UpdatedField1 string
}
func (t *V4) ConvertFrom(from interface{}) error {
if c, ok := from.(V3); ok { // forward migration
t.UpdatedField1 = c.Field3
}
return nil
}
// a struct not in the chain
type Invalid struct{}
|
