Add unit test for new Kafka client (#5570)

* Add unit test for new Kafka client

common/messaging/kafka/client_impl_test.go

@@ -0,0 +1,147 @@
+// The MIT License (MIT)
+
+// Copyright (c) 2017-2020 Uber Technologies Inc.
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+package kafka
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/uber-go/tally"
+
+	"github.com/uber/cadence/common/config"
+	"github.com/uber/cadence/common/log/testlogger"
+	"github.com/uber/cadence/common/metrics"
+)
+
+func TestNewKafkaClient(t *testing.T) {
+	metricsClient := metrics.NewClient(tally.NoopScope, metrics.History)
+	logger := testlogger.New(t)
+	testCases := []struct {
+		name        string
+		config      *config.KafkaConfig
+		checkApp    bool
+		expectedErr string
+	}{
+		{
+			name: "Missing clusters",
+			config: &config.KafkaConfig{
+				Clusters: map[string]config.ClusterConfig{},
+			},
+			checkApp:    true,
+			expectedErr: "Empty Kafka Cluster Config",
+		},
+		{
+			name: "Missing topics",
+			config: &config.KafkaConfig{
+				Clusters: map[string]config.ClusterConfig{
+					"testCluster": {
+						Brokers: []string{"testBrokers"},
+					},
+				},
+				Topics: map[string]config.TopicConfig{},
+			},
+			checkApp:    true,
+			expectedErr: "Empty Topics Config",
+		},
+		{
+			name: "Missing Applications",
+			config: &config.KafkaConfig{
+				Clusters: map[string]config.ClusterConfig{
+					"test-cluster": {
+						Brokers: []string{"test-brokers"},
+					},
+				},
+				Topics: map[string]config.TopicConfig{
+					"test-topic": {
+						Cluster: "test-cluster",
+					},
+				},
+				Applications: map[string]config.TopicList{},
+			},
+			checkApp:    true,
+			expectedErr: "Empty Applications Config",
+		},
+		{
+			name: "Missing topics config",
+			config: &config.KafkaConfig{
+				Clusters: map[string]config.ClusterConfig{
+					"test-cluster": {
+						Brokers: []string{"test-brokers"},
+					},
+				},
+				Topics: map[string]config.TopicConfig{
+					"test-topic": {
+						Cluster: "test-cluster",
+					},
+				},
+				Applications: map[string]config.TopicList{
+					"test-app": {
+						Topic:    "test-topic",
+						DLQTopic: "test-topic-dlq",
+					},
+				},
+			},
+			checkApp:    true,
+			expectedErr: "Missing Topic Config for Topic test-topic-dlq",
+		},
+		{
+			name: "Normal Case",
+			config: &config.KafkaConfig{
+				Clusters: map[string]config.ClusterConfig{
+					"test-cluster": {
+						Brokers: []string{"test-brokers"},
+					},
+				},
+				Topics: map[string]config.TopicConfig{
+					"test-topic": {
+						Cluster: "test-cluster",
+					},
+					"test-topic-dlq": {
+						Cluster: "test-cluster",
+					},
+				},
+				Applications: map[string]config.TopicList{
+					"test-app": {
+						Topic:    "test-topic",
+						DLQTopic: "test-topic-dlq",
+					},
+				},
+			},
+			checkApp: true,
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			defer func() {
+				if r := recover(); r != nil {
+					assert.Equal(t, tc.expectedErr, r)
+				}
+			}()
+			kafkaClient := NewKafkaClient(tc.config, metricsClient, logger, nil, tc.checkApp)
+			// Type assert to *clientImpl to access struct fields
+			client, ok := kafkaClient.(*clientImpl)
+			assert.True(t, ok, "Expected kafkaClient to be of type *clientImpl")
+			assert.Equal(t, tc.config, client.config)
+		})
+	}
+}