Fix port selection in and reenable the stats_plugin_end2end_test. (#25)

Author: isturdy

opencensus/plugins/BUILD

@@ -58,21 +58,19 @@ cc_library(
 
 # TODO: grpc_plugin_end2end_test
 
-# TODO: Enable this test:
-# cc_test(
-#     name = "stats_plugin_end2end_test",
-#     srcs = ["internal/stats_plugin_end2end_test.cc"],
-#     copts = TEST_COPTS,
-#     linkopts = [
-#         "-pthread",
-#     ],
-#     deps = [
-#         ":grpc_plugin",
-#         "//opencensus/plugins/internal/testing:echo_proto",
-#         "//opencensus/stats",
-#         "@com_github_grpc_grpc//:grpc++",
-#         "@com_github_grpc_grpc//test/core/util:grpc_test_util_base",
-#         "@com_google_absl//absl/strings",
-#         "@com_google_googletest//:gtest_main",
-#     ],
-# )
+cc_test(
+    name = "stats_plugin_end2end_test",
+    srcs = ["internal/stats_plugin_end2end_test.cc"],
+    copts = TEST_COPTS,
+    linkopts = [
+        "-pthread",
+    ],
+    deps = [
+        ":grpc_plugin",
+        "//opencensus/plugins/internal/testing:echo_proto",
+        "//opencensus/stats",
+        "@com_github_grpc_grpc//:grpc++",
+        "@com_google_absl//absl/strings",
+        "@com_google_googletest//:gtest_main",
+    ],
+)

opencensus/plugins/internal/stats_plugin_end2end_test.cc

@@ -24,7 +24,6 @@
 #include "opencensus/plugins/grpc_plugin.h"
 #include "opencensus/plugins/internal/testing/echo.grpc.pb.h"
 #include "opencensus/stats/stats.h"
-#include "test/core/util/port.h"
 
 namespace opencensus {
 namespace testing {
@@ -51,12 +50,15 @@ class StatsPluginEnd2EndTest : public ::testing::Test {
   void SetUp() {
     // Set up a synchronous server on a different thread to avoid the asynch
     // interface.
-    server_address_ = absl::StrCat("[::]:", grpc_pick_unused_port_or_die());
     ::grpc::ServerBuilder builder;
-    builder.AddListeningPort(server_address_,
-                             ::grpc::InsecureServerCredentials());
+    int port;
+    builder.AddListeningPort("[::]:0", ::grpc::InsecureServerCredentials(),
+                             &port);
     builder.RegisterService(&service_);
     server_ = builder.BuildAndStart();
+    ASSERT_NE(nullptr, server_);
+    ASSERT_NE(0, port);
+    server_address_ = absl::StrCat("[::]:", port);
     server_thread_ = std::thread(&StatsPluginEnd2EndTest::RunServerLoop, this);
 
     stub_ = EchoService::NewStub(::grpc::CreateChannel(