Add macos tests to circleci (facebook#7536)

Summary:
as title

Pull Request resolved: facebook#7536

Test Plan: see the new `build-macos` tests pass in circleci

Reviewed By: jay-zhuang

Differential Revision: D24243218

Pulled By: cheng-chang

fbshipit-source-id: 9b5f8a859e54c99a9ebe7efff6f336458a5d42de

.circleci/config.yml

@@ -10,9 +10,26 @@ aliases:
     only_for_branches: master
 
 commands:
+  install-pyenv-on-macos:
+    steps:
+      - run:
+          name: Install pyenv on macos
+          command: |
+            HOMEBREW_NO_AUTO_UPDATE=1 brew install pyenv
+
+  increase-max-open-files-on-macos:
+    steps:
+      - run:
+          name: Increase max open files
+          command: |
+            sudo sysctl -w kern.maxfiles=1048576
+            sudo sysctl -w kern.maxfilesperproc=1048576
+            sudo launchctl limit maxfiles 1048576
+
   pre-steps:
     steps:
       - checkout
+      - run: pyenv install --skip-existing 3.5.9
       - run: pyenv global 3.5.9
       - run:
           name: Setup Environment Variables
@@ -46,6 +63,13 @@ commands:
           name: Install gflags
           command: |
             sudo apt-get update -y && sudo apt-get install -y libgflags-dev
+  
+  install-gflags-on-macos:
+    steps:
+      - run:
+          name: Install gflags on macos
+          command: |
+            HOMEBREW_NO_AUTO_UPDATE=1 brew install gflags
 
   install-gtest-parallel:
     steps:
@@ -63,6 +87,17 @@ executors:
       shell: bash.exe
 
 jobs:
+  build-macos:
+    macos:
+      xcode: 11.3.0
+    steps:
+      - increase-max-open-files-on-macos
+      - install-pyenv-on-macos
+      - pre-steps
+      - install-gflags-on-macos
+      - run: ulimit -S -n 1048576 && OPT=-DCIRCLECI make V=1 J=32 -j32 check | .circleci/cat_ignore_eagain
+      - post-steps
+
   build-linux:
     machine:
       image: ubuntu-1604:202007-01
@@ -419,3 +454,6 @@ workflows:
   build-linux-gcc-4-8:
     jobs:
       - build-linux-gcc-4-8
+  build-macos:
+    jobs:
+      - build-macos

util/rate_limiter_test.cc

@@ -59,7 +59,7 @@ TEST_F(RateLimiterTest, Modes) {
   }
 }
 
-#if !(defined(TRAVIS) && defined(OS_MACOSX))
+#if !((defined(TRAVIS) || defined(CIRCLECI)) && defined(OS_MACOSX))
 TEST_F(RateLimiterTest, Rate) {
   auto* env = Env::Default();
   struct Arg {