Add initial backend tests

Signed-off-by: Noble Mittal <[email protected]>

go/stats/opentsdb/backend_test.go

@@ -0,0 +1,78 @@
+/*
+Copyright 2024 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 opentsdb
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type mockWriter struct {
+	data []*DataPoint
+}
+
+func (mw *mockWriter) Write(data []*DataPoint) error {
+	mw.data = data
+	return nil
+}
+
+type mockVariable struct{}
+
+func (mv *mockVariable) Help() string {
+	return ""
+}
+
+func (mv *mockVariable) String() string {
+	return ""
+}
+
+func TestPushAll(t *testing.T) {
+	mw := &mockWriter{}
+	p := "testPrefix"
+	ct := map[string]string{
+		"tag1": "value1",
+		"tag2": "value2",
+	}
+
+	b := &backend{
+		prefix:     p,
+		commonTags: ct,
+		writer:     mw,
+	}
+
+	// TODO: Add asserts
+	err := b.PushAll()
+	assert.NoError(t, err)
+}
+
+func TestPushOne(t *testing.T) {
+	mw := &mockWriter{}
+	mv := &mockVariable{}
+	b := &backend{
+		prefix:     "test",
+		commonTags: map[string]string{"tag1": "value1"},
+		writer:     mw,
+	}
+
+	// TODO: Add asserts
+	err := b.PushOne("var1", mv)
+	assert.NoError(t, err)
+
+	fmt.Println(b.collector().data)
+}