add unit test

Signed-off-by: Yashash H L <[email protected]>

pkg/mapper/server_test.go

@@ -3,10 +3,15 @@ package mapper
 import (
 	"context"
 	"os"
+	"sync"
 	"testing"
 	"time"
 
 	"github.com/stretchr/testify/assert"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+
+	mappb "github.com/numaproj/numaflow-go/pkg/apis/proto/map/v1"
 )
 
 func TestMapServer_Start(t *testing.T) {
@@ -25,8 +30,87 @@ func TestMapServer_Start(t *testing.T) {
 		return MessagesBuilder().Append(NewMessage(msg).WithKeys([]string{keys[0] + "_test"}))
 	})
 	// note: using actual uds connection
-	ctx, cancel := context.WithTimeout(context.Background(), 6*time.Second)
+	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
 	defer cancel()
 	err := NewServer(mapHandler, WithSockAddr(socketFile.Name()), WithServerInfoFilePath(serverInfoFile.Name())).Start(ctx)
 	assert.NoError(t, err)
 }
+
+// tests the case where the server is shutdown gracefully when a panic occurs in the map handler
+func TestMapServer_GracefulShutdown(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
+	defer cancel()
+
+	dir := t.TempDir()
+	socketFile, _ := os.Create(dir + "/test.sock")
+	defer func() {
+		_ = os.RemoveAll(socketFile.Name())
+	}()
+
+	serverInfoFile, _ := os.Create(dir + "/numaflow-test-info")
+	defer func() {
+		_ = os.RemoveAll(serverInfoFile.Name())
+	}()
+
+	var mapHandler = MapperFunc(func(ctx context.Context, keys []string, d Datum) Messages {
+		msg := d.Value()
+		if keys[0] == "key2" {
+			time.Sleep(20 * time.Millisecond)
+			panic("panic test")
+		}
+		time.Sleep(50 * time.Millisecond)
+		return MessagesBuilder().Append(NewMessage(msg).WithKeys([]string{keys[0] + "_test"}))
+	})
+
+	done := make(chan struct{})
+	go func() {
+		err := NewServer(mapHandler, WithSockAddr(socketFile.Name()), WithServerInfoFilePath(socketFile.Name())).Start(ctx)
+		assert.NoError(t, err)
+		close(done)
+	}()
+
+	// wait for the server to start
+	time.Sleep(10 * time.Millisecond)
+
+	// create a client
+	conn, err := grpc.Dial(
+		"unix://"+socketFile.Name(),
+		grpc.WithTransportCredentials(insecure.NewCredentials()),
+	)
+	if err != nil {
+		t.Fatalf("Failed to dial server: %v", err)
+	}
+	defer conn.Close()
+
+	client := mappb.NewMapClient(conn)
+	// send two map requests with key1 and key2 as keys simultaneously
+	keys := []string{"key1", "key2"}
+	var wg sync.WaitGroup
+	for _, key := range keys {
+		wg.Add(1)
+		go func(key string) {
+			defer wg.Done()
+			req := &mappb.MapRequest{
+				Keys: []string{key},
+			}
+
+			resp, err := client.MapFn(ctx, req)
+			// since there is a panic in the map handler for key2, we should get an error
+			// other requests should be successful
+			if key == "key2" {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+				assert.NotNil(t, resp)
+			}
+		}(key)
+	}
+
+	wg.Wait()
+	// wait for the server to shutdown gracefully because of the panic
+	select {
+	case <-ctx.Done():
+		t.Fatal("server did not shutdown gracefully")
+	case <-done:
+	}
+}