Replace RequestContext::create with RequestContextScopeGuard in tests

Summary: RequestContextScopeGuard should be preferred to RequestContext::create because it makes sure that RequestContext is cleared afterwards - need to create more examples of this in the codebase, migrating unit tests should be safe

Reviewed By: interwq

Differential Revision: D3489969

fbshipit-source-id: 202fec93116db3d435c108fafecad26a4ed9b603

folly/fibers/test/FibersTest.cpp

@@ -1267,18 +1267,21 @@ TEST(FiberManager, RequestContext) {
   folly::fibers::Baton baton3;
   folly::fibers::Baton baton4;
 
-  folly::RequestContext::create();
+  {
+    folly::RequestContextScopeGuard rctx;
     auto rcontext1 = folly::RequestContext::get();
     fm.addTask([&]() {
       EXPECT_EQ(rcontext1, folly::RequestContext::get());
-    baton1.wait([&]() { EXPECT_EQ(rcontext1, folly::RequestContext::get()); });
+      baton1.wait(
+          [&]() { EXPECT_EQ(rcontext1, folly::RequestContext::get()); });
       EXPECT_EQ(rcontext1, folly::RequestContext::get());
       runInMainContext(
           [&]() { EXPECT_EQ(rcontext1, folly::RequestContext::get()); });
       checkRun1 = true;
     });
-
-  folly::RequestContext::create();
+  }
+  {
+    folly::RequestContextScopeGuard rctx;
     auto rcontext2 = folly::RequestContext::get();
     fm.addTaskRemote([&]() {
       EXPECT_EQ(rcontext2, folly::RequestContext::get());
@@ -1286,8 +1289,9 @@ TEST(FiberManager, RequestContext) {
       EXPECT_EQ(rcontext2, folly::RequestContext::get());
       checkRun2 = true;
     });
-
-  folly::RequestContext::create();
+  }
+  {
+    folly::RequestContextScopeGuard rctx;
     auto rcontext3 = folly::RequestContext::get();
     fm.addTaskFinally(
         [&]() {
@@ -1301,17 +1305,19 @@ TEST(FiberManager, RequestContext) {
           EXPECT_EQ(rcontext3, folly::RequestContext::get());
           checkRun3 = true;
         });
-
+  }
+  {
     folly::RequestContext::setContext(nullptr);
     fm.addTask([&]() {
-    folly::RequestContext::create();
+      folly::RequestContextScopeGuard rctx;
       auto rcontext4 = folly::RequestContext::get();
       baton4.wait();
       EXPECT_EQ(rcontext4, folly::RequestContext::get());
       checkRun4 = true;
     });
-
-  folly::RequestContext::create();
+  }
+  {
+    folly::RequestContextScopeGuard rctx;
     auto rcontext = folly::RequestContext::get();
 
     fm.loopUntilNoReady();
@@ -1340,6 +1346,7 @@ TEST(FiberManager, RequestContext) {
     fm.loopUntilNoReady();
     EXPECT_TRUE(checkRun4);
     EXPECT_EQ(rcontext, folly::RequestContext::get());
+  }
 }
 
 TEST(FiberManager, resizePeriodically) {

folly/futures/test/ContextTest.cpp

@@ -30,7 +30,7 @@ class TestData : public RequestData {
 TEST(Context, basic) {
 
   // Start a new context
-  RequestContext::create();
+  folly::RequestContextScopeGuard rctx;
 
   EXPECT_EQ(nullptr, RequestContext::get()->getContextData("test"));
 

folly/futures/test/FutureTest.cpp

@@ -822,10 +822,12 @@ TEST(Future, RequestContext) {
     bool value;
   };
 
+  Promise<int> p1, p2;
+  {
     NewThreadExecutor e;
-  RequestContext::create();
-  RequestContext::get()->setContextData("key",
-      folly::make_unique<MyRequestData>(true));
+    folly::RequestContextScopeGuard rctx;
+    RequestContext::get()->setContextData(
+        "key", folly::make_unique<MyRequestData>(true));
     auto checker = [](int lineno) {
       return [lineno](Try<int>&& /* t */) {
         auto d = static_cast<MyRequestData*>(
@@ -839,13 +841,13 @@ TEST(Future, RequestContext) {
     e.setHandlesPriorities();
     makeFuture(2).via(&e).then(checker(__LINE__));
 
-  Promise<int> p1, p2;
     p1.getFuture().then(checker(__LINE__));
 
     e.setThrowsOnAdd();
     p2.getFuture().via(&e).then(checker(__LINE__));
-
-  RequestContext::create();
+  }
+  // Assert that no RequestContext is set
+  EXPECT_FALSE(RequestContext::saveContext());
   p1.setValue(3);
   p2.setValue(4);
 }