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// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package jsonx
import (
"errors"
"testing"
"github.com/go-json-experiment/json"
"github.com/go-json-experiment/json/jsontext"
"github.com/google/go-cmp/cmp"
"tailscale.com/types/ptr"
)
type Interface interface {
implementsInterface()
}
type Foo string
func (Foo) implementsInterface() {}
type Bar int
func (Bar) implementsInterface() {}
type Baz struct{ Fizz, Buzz string }
func (*Baz) implementsInterface() {}
var interfaceCoders = MakeInterfaceCoders(map[string]Interface{
"Foo": Foo(""),
"Bar": (*Bar)(nil),
"Baz": (*Baz)(nil),
})
type InterfaceWrapper struct{ Interface }
func (w InterfaceWrapper) MarshalJSONTo(enc *jsontext.Encoder) error {
return interfaceCoders.Marshal(enc, &w.Interface)
}
func (w *InterfaceWrapper) UnmarshalJSONFrom(dec *jsontext.Decoder) error {
return interfaceCoders.Unmarshal(dec, &w.Interface)
}
func TestInterfaceCoders(t *testing.T) {
var opts json.Options = json.JoinOptions(
json.WithMarshalers(json.MarshalToFunc(interfaceCoders.Marshal)),
json.WithUnmarshalers(json.UnmarshalFromFunc(interfaceCoders.Unmarshal)),
)
errSkipMarshal := errors.New("skip marshal")
makeFiller := func() InterfaceWrapper {
return InterfaceWrapper{&Baz{"fizz", "buzz"}}
}
for _, tt := range []struct {
label string
wantVal InterfaceWrapper
wantJSON string
wantMarshalError error
wantUnmarshalError error
}{{
label: "Null",
wantVal: InterfaceWrapper{},
wantJSON: `null`,
}, {
label: "Foo",
wantVal: InterfaceWrapper{Foo("hello")},
wantJSON: `{"Foo":"hello"}`,
}, {
label: "BarPointer",
wantVal: InterfaceWrapper{ptr.To(Bar(5))},
wantJSON: `{"Bar":5}`,
}, {
label: "BarValue",
wantVal: InterfaceWrapper{Bar(5)},
// NOTE: We could handle BarValue just like BarPointer,
// but round-trip marshal/unmarshal would not be identical.
wantMarshalError: errUnknownTypeName,
}, {
label: "Baz",
wantVal: InterfaceWrapper{&Baz{"alpha", "omega"}},
wantJSON: `{"Baz":{"Fizz":"alpha","Buzz":"omega"}}`,
}, {
label: "Unknown",
wantVal: makeFiller(),
wantJSON: `{"Unknown":[1,2,3]}`,
wantMarshalError: errSkipMarshal,
wantUnmarshalError: errUnknownTypeName,
}, {
label: "Empty",
wantVal: makeFiller(),
wantJSON: `{}`,
wantMarshalError: errSkipMarshal,
wantUnmarshalError: errNonSingularValue,
}, {
label: "Duplicate",
wantVal: InterfaceWrapper{Foo("hello")}, // first entry wins
wantJSON: `{"Foo":"hello","Bar":5}`,
wantMarshalError: errSkipMarshal,
wantUnmarshalError: errNonSingularValue,
}} {
t.Run(tt.label, func(t *testing.T) {
if tt.wantMarshalError != errSkipMarshal {
switch gotJSON, err := json.Marshal(&tt.wantVal); {
case !errors.Is(err, tt.wantMarshalError):
t.Fatalf("json.Marshal(%v) error = %v, want %v", tt.wantVal, err, tt.wantMarshalError)
case string(gotJSON) != tt.wantJSON:
t.Fatalf("json.Marshal(%v) = %s, want %s", tt.wantVal, gotJSON, tt.wantJSON)
}
switch gotJSON, err := json.Marshal(&tt.wantVal.Interface, opts); {
case !errors.Is(err, tt.wantMarshalError):
t.Fatalf("json.Marshal(%v) error = %v, want %v", tt.wantVal, err, tt.wantMarshalError)
case string(gotJSON) != tt.wantJSON:
t.Fatalf("json.Marshal(%v) = %s, want %s", tt.wantVal, gotJSON, tt.wantJSON)
}
}
if tt.wantJSON != "" {
gotVal := makeFiller()
if err := json.Unmarshal([]byte(tt.wantJSON), &gotVal); !errors.Is(err, tt.wantUnmarshalError) {
t.Fatalf("json.Unmarshal(%v) error = %v, want %v", tt.wantJSON, err, tt.wantUnmarshalError)
}
if d := cmp.Diff(gotVal, tt.wantVal); d != "" {
t.Fatalf("json.Unmarshal(%v):\n%s", tt.wantJSON, d)
}
gotVal = makeFiller()
if err := json.Unmarshal([]byte(tt.wantJSON), &gotVal.Interface, opts); !errors.Is(err, tt.wantUnmarshalError) {
t.Fatalf("json.Unmarshal(%v) error = %v, want %v", tt.wantJSON, err, tt.wantUnmarshalError)
}
if d := cmp.Diff(gotVal, tt.wantVal); d != "" {
t.Fatalf("json.Unmarshal(%v):\n%s", tt.wantJSON, d)
}
}
})
}
}
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