Make exporters/trace/stdout consistent with the stats one. (#101)

This also simplifies the public API.

Author: g-easy

opencensus/exporters/trace/stdout/internal/stdout_exporter.cc

@@ -15,15 +15,24 @@
 #include "opencensus/exporters/trace/stdout/stdout_exporter.h"
 
 #include <iostream>
+#include <vector>
 
 #include "absl/base/macros.h"
 #include "absl/memory/memory.h"
+#include "opencensus/trace/exporter/span_data.h"
+#include "opencensus/trace/exporter/span_exporter.h"
 
 namespace opencensus {
 namespace exporters {
 namespace trace {
 
-void StdoutExporter::Export(
+class StdoutExporter::Handler
+    : public ::opencensus::trace::exporter::SpanExporter::Handler {
+  void Export(const std::vector<::opencensus::trace::exporter::SpanData>& spans)
+      override;
+};
+
+void StdoutExporter::Handler::Export(
     const std::vector<::opencensus::trace::exporter::SpanData>& spans) {
   for (const auto& span : spans) {
     std::cout << span.DebugString() << "\n";
@@ -32,7 +41,7 @@ void StdoutExporter::Export(
 
 void StdoutExporter::Register() {
   ::opencensus::trace::exporter::SpanExporter::RegisterHandler(
-      absl::make_unique<StdoutExporter>());
+      absl::make_unique<Handler>());
 }
 
 }  // namespace trace

opencensus/exporters/trace/stdout/internal/stdout_exporter_test.cc

@@ -24,16 +24,9 @@ namespace exporters {
 namespace trace {
 namespace {
 
-class TraceExporterTest : public ::testing::Test {
- public:
-  TraceExporterTest() {}
-
- protected:
-  StdoutExporter handler_;
-};
-
-TEST_F(TraceExporterTest, ExportTrace) {
-  ::opencensus::trace::AlwaysSampler sampler;
+TEST(TraceExporterTest, ExportTrace) {
+  StdoutExporter::Register();
+  static ::opencensus::trace::AlwaysSampler sampler;
   ::opencensus::trace::StartSpanOptions opts = {&sampler};
 
   auto span1 = ::opencensus::trace::Span::StartSpan("Span1", nullptr, opts);
@@ -45,10 +38,9 @@ TEST_F(TraceExporterTest, ExportTrace) {
   span3.End();
   span2.End();
   span1.End();
-  std::vector<::opencensus::trace::exporter::SpanData> spans =
-      ::opencensus::trace::exporter::LocalSpanStore::GetSpans();
 
-  handler_.Export(spans);
+  // Wait for exporter.
+  absl::SleepFor(absl::Milliseconds(5200));
 }
 
 }  // namespace

opencensus/exporters/trace/stdout/stdout_exporter.h

@@ -15,22 +15,16 @@
 #ifndef OPENCENSUS_EXPORTERS_TRACE_STDOUT_STDOUT_EXPORTER_H_
 #define OPENCENSUS_EXPORTERS_TRACE_STDOUT_STDOUT_EXPORTER_H_
 
-#include <vector>
-
-#include "opencensus/trace/exporter/span_data.h"
-#include "opencensus/trace/exporter/span_exporter.h"
-
 namespace opencensus {
 namespace exporters {
 namespace trace {
 
-class StdoutExporter
-    : public ::opencensus::trace::exporter::SpanExporter::Handler {
+class StdoutExporter {
  public:
-  void Export(const std::vector<::opencensus::trace::exporter::SpanData>& spans)
-      override;
-
   static void Register();
+
+ private:
+  class Handler;
 };
 
 }  // namespace trace