PLT-8131 (part2) Add plugin key value store support (#7902)

* Add plugin key value store support

* Add localization strings

* Updates per feedback

store/storetest/plugin_store.go

@@ -0,0 +1,69 @@
+// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package storetest
+
+import (
+	"testing"
+
+	"github.com/mattermost/mattermost-server/model"
+	"github.com/mattermost/mattermost-server/store"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPluginStore(t *testing.T, ss store.Store) {
+	t.Run("PluginSaveGet", func(t *testing.T) { testPluginSaveGet(t, ss) })
+	t.Run("PluginDelete", func(t *testing.T) { testPluginDelete(t, ss) })
+}
+
+func testPluginSaveGet(t *testing.T, ss store.Store) {
+	kv := &model.PluginKeyValue{
+		PluginId: model.NewId(),
+		Key:      model.NewId(),
+		Value:    []byte(model.NewId()),
+	}
+
+	if result := <-ss.Plugin().SaveOrUpdate(kv); result.Err != nil {
+		t.Fatal(result.Err)
+	}
+
+	defer func() {
+		<-ss.Plugin().Delete(kv.PluginId, kv.Key)
+	}()
+
+	if result := <-ss.Plugin().Get(kv.PluginId, kv.Key); result.Err != nil {
+		t.Fatal(result.Err)
+	} else {
+		received := result.Data.(*model.PluginKeyValue)
+		assert.Equal(t, kv.PluginId, received.PluginId)
+		assert.Equal(t, kv.Key, received.Key)
+		assert.Equal(t, kv.Value, received.Value)
+	}
+
+	// Try inserting when already exists
+	kv.Value = []byte(model.NewId())
+	if result := <-ss.Plugin().SaveOrUpdate(kv); result.Err != nil {
+		t.Fatal(result.Err)
+	}
+
+	if result := <-ss.Plugin().Get(kv.PluginId, kv.Key); result.Err != nil {
+		t.Fatal(result.Err)
+	} else {
+		received := result.Data.(*model.PluginKeyValue)
+		assert.Equal(t, kv.PluginId, received.PluginId)
+		assert.Equal(t, kv.Key, received.Key)
+		assert.Equal(t, kv.Value, received.Value)
+	}
+}
+
+func testPluginDelete(t *testing.T, ss store.Store) {
+	kv := store.Must(ss.Plugin().SaveOrUpdate(&model.PluginKeyValue{
+		PluginId: model.NewId(),
+		Key:      model.NewId(),
+		Value:    []byte(model.NewId()),
+	})).(*model.PluginKeyValue)
+
+	if result := <-ss.Plugin().Delete(kv.PluginId, kv.Key); result.Err != nil {
+		t.Fatal(result.Err)
+	}
+}