From 1f1e288ee3f9654de1cee1819c6f3b79b1ed488b Mon Sep 17 00:00:00 2001
From: Gregory Oschwald <goschwald@maxmind.com>
Date: Wed, 19 Aug 2020 12:11:25 -0700
Subject: [PATCH] Add basic test for deserializer

---
 deserializer.go deserializer_test.go | 119 +++++++++++++++++++++++++++
 go.sum                               |   8 --
 reader_test.go                       |   4 +
 3 files changed, 123 insertions(+), 8 deletions(-)
 create mode 100644 deserializer.go deserializer_test.go

diff --git a/deserializer.go deserializer_test.go b/deserializer.go deserializer_test.go
new file mode 100644
index 0000000..8b15fee
--- /dev/null
+++ b/deserializer.go deserializer_test.go	
@@ -0,0 +1,119 @@
+package maxminddb
+
+import (
+	"math/big"
+	"net"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestDecodingToDeserializer(t *testing.T) {
+	reader, err := Open(testFile("MaxMind-DB-test-decoder.mmdb"))
+	require.NoError(t, err, "unexpected error while opening database: %v", err)
+
+	dser := testDeserializer{}
+	err = reader.Lookup(net.ParseIP("::1.1.1.0"), &dser)
+	require.NoError(t, err, "unexpected error while doing lookup: %v", err)
+
+	checkDecodingToInterface(t, dser.rv)
+}
+
+type stackValue struct {
+	value  interface{}
+	curNum int
+}
+
+type testDeserializer struct {
+	stack []*stackValue
+	rv    interface{}
+	key   *string
+}
+
+func (d *testDeserializer) ShouldSkip(offset uintptr) (bool, error) {
+	return false, nil
+}
+
+func (d *testDeserializer) StartSlice(size uint) error {
+	return d.add(make([]interface{}, size))
+}
+
+func (d *testDeserializer) StartMap(size uint) error {
+	return d.add(map[string]interface{}{})
+}
+
+func (d *testDeserializer) End() error {
+	d.stack = d.stack[:len(d.stack)-1]
+	return nil
+}
+
+func (d *testDeserializer) String(v string) error {
+	return d.add(v)
+}
+
+func (d *testDeserializer) Float64(v float64) error {
+	return d.add(v)
+}
+
+func (d *testDeserializer) Bytes(v []byte) error {
+	return d.add(v)
+}
+
+func (d *testDeserializer) Uint16(v uint16) error {
+	return d.add(uint64(v))
+}
+
+func (d *testDeserializer) Uint32(v uint32) error {
+	return d.add(uint64(v))
+}
+
+func (d *testDeserializer) Int32(v int32) error {
+	return d.add(int(v))
+}
+
+func (d *testDeserializer) Uint64(v uint64) error {
+	return d.add(v)
+}
+
+func (d *testDeserializer) Uint128(v *big.Int) error {
+	return d.add(v)
+}
+
+func (d *testDeserializer) Bool(v bool) error {
+	return d.add(v)
+}
+
+func (d *testDeserializer) Float32(v float32) error {
+	return d.add(v)
+}
+
+func (d *testDeserializer) add(v interface{}) error {
+	if len(d.stack) == 0 {
+		d.rv = v
+	} else {
+		top := d.stack[len(d.stack)-1]
+		switch parent := top.value.(type) {
+		case map[string]interface{}:
+			if d.key == nil {
+				key := v.(string)
+				d.key = &key
+			} else {
+				parent[*d.key] = v
+				d.key = nil
+			}
+
+		case []interface{}:
+			parent[top.curNum] = v
+			top.curNum++
+		default:
+		}
+	}
+
+	switch v := v.(type) {
+	case map[string]interface{}, []interface{}:
+		d.stack = append(d.stack, &stackValue{value: v})
+	default:
+	}
+
+	return nil
+}
diff --git a/go.sum b/go.sum
index 45bf757..ae4f4e7 100644
--- a/go.sum
+++ b/go.sum
@@ -4,19 +4,11 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0 h1:4G4v2dO3VZwixGIRoQ5Lfboy6nUhCyYzaqnIAPPhYs4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
-github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
-github.com/stretchr/testify v1.5.0 h1:DMOzIV76tmoDNE9pX6RSN0aDtCYeCg5VueieJaAo1uw=
-github.com/stretchr/testify v1.5.0/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
-github.com/stretchr/testify v1.5.1 h1:nOGnQDM7FYENwehXlg/kFVnos3rEvtKTjRvOWSzb6H4=
-github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
 github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0=
 github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 golang.org/x/sys v0.0.0-20191224085550-c709ea063b76 h1:Dho5nD6R3PcW2SH1or8vS0dszDaXRxIw55lBX7XiE5g=
 golang.org/x/sys v0.0.0-20191224085550-c709ea063b76/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
-gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/reader_test.go b/reader_test.go
index 863462d..19031c2 100644
--- a/reader_test.go
+++ b/reader_test.go
@@ -203,6 +203,10 @@ func TestDecodingToInterface(t *testing.T) {
 	err = reader.Lookup(net.ParseIP("::1.1.1.0"), &recordInterface)
 	require.NoError(t, err, "unexpected error while doing lookup: %v", err)
 
+	checkDecodingToInterface(t, recordInterface)
+}
+
+func checkDecodingToInterface(t *testing.T, recordInterface interface{}) {
 	record := recordInterface.(map[string]interface{})
 	assert.Equal(t, []interface{}{uint64(1), uint64(2), uint64(3)}, record["array"])
 	assert.Equal(t, true, record["boolean"])