add opentracing spans for metrics

vendor/github.com/Shopify/sarama/config_test.go

@@ -0,0 +1,70 @@
+package sarama
+
+import (
+	"os"
+	"testing"
+
+	"github.com/rcrowley/go-metrics"
+)
+
+func TestDefaultConfigValidates(t *testing.T) {
+	config := NewConfig()
+	if err := config.Validate(); err != nil {
+		t.Error(err)
+	}
+	if config.MetricRegistry == nil {
+		t.Error("Expected non nil metrics.MetricRegistry, got nil")
+	}
+}
+
+func TestInvalidClientIDConfigValidates(t *testing.T) {
+	config := NewConfig()
+	config.ClientID = "foo:bar"
+	if err := config.Validate(); string(err.(ConfigurationError)) != "ClientID is invalid" {
+		t.Error("Expected invalid ClientID, got ", err)
+	}
+}
+
+func TestEmptyClientIDConfigValidates(t *testing.T) {
+	config := NewConfig()
+	config.ClientID = ""
+	if err := config.Validate(); string(err.(ConfigurationError)) != "ClientID is invalid" {
+		t.Error("Expected invalid ClientID, got ", err)
+	}
+}
+
+func TestLZ4ConfigValidation(t *testing.T) {
+	config := NewConfig()
+	config.Producer.Compression = CompressionLZ4
+	if err := config.Validate(); string(err.(ConfigurationError)) != "lz4 compression requires Version >= V0_10_0_0" {
+		t.Error("Expected invalid lz4/kakfa version error, got ", err)
+	}
+	config.Version = V0_10_0_0
+	if err := config.Validate(); err != nil {
+		t.Error("Expected lz4 to work, got ", err)
+	}
+}
+
+// This example shows how to integrate with an existing registry as well as publishing metrics
+// on the standard output
+func ExampleConfig_metrics() {
+	// Our application registry
+	appMetricRegistry := metrics.NewRegistry()
+	appGauge := metrics.GetOrRegisterGauge("m1", appMetricRegistry)
+	appGauge.Update(1)
+
+	config := NewConfig()
+	// Use a prefix registry instead of the default local one
+	config.MetricRegistry = metrics.NewPrefixedChildRegistry(appMetricRegistry, "sarama.")
+
+	// Simulate a metric created by sarama without starting a broker
+	saramaGauge := metrics.GetOrRegisterGauge("m2", config.MetricRegistry)
+	saramaGauge.Update(2)
+
+	metrics.WriteOnce(appMetricRegistry, os.Stdout)
+	// Output:
+	// gauge m1
+	//   value:               1
+	// gauge sarama.m2
+	//   value:               2
+}