Create CollectMutation test

Co-authored-by: iknite <[email protected]>

balloon/navigator/test_util.go

@@ -28,6 +28,13 @@ type FakePosition struct {
 	Hght uint16
 }
 
+func NewFakePosition(index []byte, height uint16) *FakePosition {
+	return &FakePosition{
+		Idx:  index,
+		Hght: height,
+	}
+}
+
 func (p FakePosition) Index() []byte {
 	return p.Idx
 }

balloon/visitor/collect_test.go

@@ -0,0 +1,73 @@
+/*
+   Copyright 2018 Banco Bilbao Vizcaya Argentaria, S.A.
+
+   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 visitor
+
+import (
+	"testing"
+
+	assert "github.com/stretchr/testify/require"
+
+	"github.com/bbva/qed/balloon/navigator"
+	"github.com/bbva/qed/hashing"
+	"github.com/bbva/qed/storage"
+)
+
+var fakePos = navigator.NewFakePosition
+
+func TestCollect(t *testing.T) {
+
+	testCases := []struct {
+		visitable         Visitable
+		expectedMutations []*storage.Mutation
+	}{
+		{
+			visitable: NewRoot(fakePos([]byte{0}, 8),
+				NewNode(fakePos([]byte{0}, 9),
+					NewCollectable(NewCached(fakePos([]byte{0}, 7), hashing.Digest{0})),
+					NewNode(fakePos([]byte{0}, 9),
+						NewCollectable(NewCached(fakePos([]byte{0}, 6), hashing.Digest{1})),
+						NewLeaf(fakePos([]byte{0}, 1), hashing.Digest{0}),
+					),
+				),
+				NewNode(fakePos([]byte{0}, 9),
+					NewLeaf(fakePos([]byte{0}, 1), hashing.Digest{0}),
+					NewCollectable(NewCached(fakePos([]byte{0}, 8), hashing.Digest{2})),
+				),
+			),
+			expectedMutations: []*storage.Mutation{
+				{storage.HyperCachePrefix, fakePos([]byte{0}, 7).Bytes(), hashing.Digest{0}},
+				{storage.HyperCachePrefix, fakePos([]byte{0}, 6).Bytes(), hashing.Digest{1}},
+				{storage.HyperCachePrefix, fakePos([]byte{0}, 8).Bytes(), hashing.Digest{2}},
+			},
+		},
+	}
+
+	for i, c := range testCases {
+		decorated := NewComputeHashVisitor(hashing.NewFakeXorHasher())
+		visitor := NewCollectMutationsVisitor(decorated, storage.HyperCachePrefix)
+		c.visitable.PostOrder(visitor)
+
+		mutations := visitor.Result()
+		assert.ElementsMatchf(
+			t,
+			mutations,
+			c.expectedMutations,
+			"Mutation error in test case %d",
+			i,
+		)
+	}
+}