sizegen: implement unit tests

Signed-off-by: Vicent Marti <[email protected]>

go/tools/sizegen/integration/integration_test.go

@@ -0,0 +1,85 @@
+/*
+Copyright 2021 The Vitess Authors.
+
+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 integration
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestTypeSizes(t *testing.T) {
+	const PtrSize = 8
+	const SliceHeaderSize = 3 * PtrSize
+	const FatPointerSize = 2 * PtrSize
+	const BucketHeaderSize = 8
+	const BucketSize = 8
+	const HashMapHeaderSize = 48
+
+	cases := []struct {
+		obj  cachedObject
+		size int64
+	}{
+		{&A{}, 16},
+		{&C{}, 16},
+		{&C{field1: &Bimpl{}}, 24},
+		{&D{}, 8},
+		{&D{field1: &Bimpl{}}, 16},
+		{&Padded{}, 24},
+
+		{&Slice1{}, 24},
+		{&Slice1{field1: []A{}}, SliceHeaderSize},
+		{&Slice1{field1: []A{{}}}, SliceHeaderSize + 16},
+		{&Slice1{field1: []A{{}, {}, {}, {}}}, SliceHeaderSize + 16*4},
+
+		{&Slice2{}, SliceHeaderSize},
+		{&Slice2{field1: []B{}}, SliceHeaderSize},
+		{&Slice2{field1: []B{&Bimpl{}}}, SliceHeaderSize + FatPointerSize*1 + 8*1},
+		{&Slice2{field1: []B{&Bimpl{}, &Bimpl{}, &Bimpl{}, &Bimpl{}}}, SliceHeaderSize + FatPointerSize*4 + 8*4},
+
+		{&Slice3{}, SliceHeaderSize},
+		{&Slice3{field1: []*Bimpl{}}, SliceHeaderSize},
+		{&Slice3{field1: []*Bimpl{nil}}, SliceHeaderSize + PtrSize*1 + 0},
+		{&Slice3{field1: []*Bimpl{nil, nil, nil, nil}}, SliceHeaderSize + PtrSize*4 + 0},
+		{&Slice3{field1: []*Bimpl{{}}}, SliceHeaderSize + PtrSize*1 + 8*1},
+		{&Slice3{field1: []*Bimpl{{}, {}, {}, {}}}, SliceHeaderSize + PtrSize*4 + 8*4},
+
+		{&Map1{field1: nil}, PtrSize},
+		{&Map1{field1: map[uint8]uint8{}}, PtrSize + HashMapHeaderSize},
+		{&Map1{field1: map[uint8]uint8{0: 0}}, PtrSize + HashMapHeaderSize + BucketHeaderSize + 1*BucketSize + 1*BucketSize + PtrSize},
+
+		{&Map2{field1: nil}, PtrSize},
+		{&Map2{field1: map[uint64]A{}}, PtrSize + HashMapHeaderSize},
+		{&Map2{field1: map[uint64]A{0: {}}}, PtrSize + HashMapHeaderSize + BucketHeaderSize + 8*BucketSize + 16*BucketSize + PtrSize},
+
+		{&Map3{field1: nil}, PtrSize},
+		{&Map3{field1: map[uint64]B{}}, PtrSize + HashMapHeaderSize},
+		{&Map3{field1: map[uint64]B{0: &Bimpl{}}}, PtrSize + HashMapHeaderSize + BucketHeaderSize + 8*BucketSize + FatPointerSize*BucketSize + PtrSize + 8},
+		{&Map3{field1: map[uint64]B{0: nil}}, PtrSize + HashMapHeaderSize + BucketHeaderSize + 8*BucketSize + FatPointerSize*BucketSize + PtrSize},
+
+		{&String1{}, PtrSize*2 + 8},
+		{&String1{field1: "1234"}, PtrSize*2 + 8 + 4},
+	}
+
+	for _, tt := range cases {
+		t.Run(fmt.Sprintf("sizeof(%T)", tt.obj), func(t *testing.T) {
+			size := tt.obj.CachedSize(true)
+			if size != tt.size {
+				t.Errorf("expected %T to be %d bytes, got %d", tt.obj, tt.size, size)
+			}
+		})
+	}
+}

go/tools/sizegen/integration/types.go

@@ -0,0 +1,76 @@
+/*
+Copyright 2021 The Vitess Authors.
+
+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.
+*/
+
+//nolint
+package integration
+
+type A struct {
+	field1 uint64
+	field2 uint64
+}
+
+type B interface {
+	iface()
+}
+
+type Bimpl struct {
+	field1 uint64
+}
+
+func (b *Bimpl) iface() {}
+
+type C struct {
+	field1 B
+}
+
+type D struct {
+	field1 *Bimpl
+}
+
+type Padded struct {
+	field1 uint64
+	field2 uint8
+	field3 uint64
+}
+
+type Slice1 struct {
+	field1 []A
+}
+
+type Slice2 struct {
+	field1 []B
+}
+
+type Slice3 struct {
+	field1 []*Bimpl
+}
+
+type Map1 struct {
+	field1 map[uint8]uint8
+}
+
+type Map2 struct {
+	field1 map[uint64]A
+}
+
+type Map3 struct {
+	field1 map[uint64]B
+}
+
+type String1 struct {
+	field1 string
+	field2 uint64
+}