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fp-go/optics/lens/iso/iso_test.go
Dr. Carsten Leue 7476b70a23 fix: add optics and consistent copyright
Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>
2023-07-23 22:05:54 +02:00

100 lines
2.3 KiB
Go

// Copyright (c) 2023 IBM Corp.
// All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package iso
import (
"testing"
EQT "github.com/IBM/fp-go/eq/testing"
F "github.com/IBM/fp-go/function"
L "github.com/IBM/fp-go/optics/lens"
LT "github.com/IBM/fp-go/optics/lens/testing"
O "github.com/IBM/fp-go/option"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
)
type (
Inner struct {
Value *int
Foo string
}
Outer struct {
inner Inner
}
)
func (outer Outer) GetInner() Inner {
return outer.inner
}
func (outer Outer) SetInner(inner Inner) Outer {
outer.inner = inner
return outer
}
func (inner Inner) GetValue() *int {
return inner.Value
}
func (inner Inner) SetValue(value *int) Inner {
inner.Value = value
return inner
}
func TestIso(t *testing.T) {
eqOptInt := O.Eq(EQT.Eq[int]())
eqOuter := EQT.Eq[Outer]()
emptyOuter := Outer{}
// iso
intIso := FromNillable[int]()
innerFromOuter := L.MakeLens((Outer).GetInner, (Outer).SetInner)
valueFromInner := L.MakeLens((Inner).GetValue, (Inner).SetValue)
optValueFromInner := F.Pipe1(
valueFromInner,
Compose[Inner](intIso),
)
optValueFromOuter := F.Pipe1(
innerFromOuter,
L.Compose[Outer](optValueFromInner),
)
// try some access
require.True(t, eqOptInt.Equals(optValueFromOuter.Get(emptyOuter), O.None[int]()))
updatedOuter := optValueFromOuter.Set(O.Some(1))(emptyOuter)
require.True(t, eqOptInt.Equals(optValueFromOuter.Get(updatedOuter), O.Some(1)))
secondOuter := optValueFromOuter.Set(O.None[int]())(updatedOuter)
require.True(t, eqOptInt.Equals(optValueFromOuter.Get(secondOuter), O.None[int]()))
// check if this obeys laws
laws := LT.AssertLaws(
t,
eqOptInt,
eqOuter,
)(optValueFromOuter)
assert.True(t, laws(emptyOuter, O.Some(2)))
}