Add an integration test

Author: matthewmcneely

dgraph/cmd/zero/zero_test.go

@@ -17,6 +17,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/docker/docker/client"
 	"github.com/stretchr/testify/require"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials/insecure"
@@ -154,3 +155,38 @@ func TestZeroHealth(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, string(body), "OK")
 }
+
+func TestZeroGracefulShutdown(t *testing.T) {
+	// This test verifies that Zero shuts down cleanly without hanging.
+	// It catches issues like closer miscount bugs where SignalAndWait() would block indefinitely.
+
+	instance := testutil.GetContainerInstance(testutil.DockerPrefix, "zero1")
+	c := instance.GetContainer()
+	require.NotNil(t, c, "zero1 container not found")
+
+	containerID := c.ID
+
+	startTime := time.Now()
+	err := testutil.DockerRun("zero1", testutil.Stop)
+	shutdownDuration := time.Since(startTime)
+
+	require.NoError(t, err, "Failed to stop zero1 container")
+	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
+	require.NoError(t, err)
+
+	inspect, err := cli.ContainerInspect(context.Background(), containerID)
+	require.NoError(t, err)
+	require.False(t, inspect.State.Running, "Container should not be running after stop")
+
+	if inspect.State.ExitCode == 137 {
+		t.Errorf("Zero was killed (exit code 137) instead of shutting down gracefully. "+
+			"This may indicate a hanging goroutine or closer miscount. Shutdown took %v", shutdownDuration)
+	}
+
+	// Restart the container so other tests can continue
+	err = testutil.DockerRun("zero1", testutil.Start)
+	require.NoError(t, err, "Failed to restart zero1 container")
+
+	err = instance.BestEffortWaitForHealthy(6080)
+	require.NoError(t, err, "Zero did not become healthy after restart")
+}