Support CO_ASSERT_THAT

Summary:
`ASSERT_THAT` is defined in gmock, this adds the equivalent for coroutine code to GmockHelper.

The implementation depends on the inclusion of GtestHelper, but to avoid forcing anyone that includes GmockHelper to also include GtestHelper I didn't add it in the file.

Would it be preferable to include the needed header?

Reviewed By: yfeldblum

Differential Revision: D29067561

fbshipit-source-id: 26aa6021efe55aa03dd7cf064563a732e47e39a1

folly/experimental/coro/GmockHelpers.h

@@ -20,6 +20,7 @@
 #include <type_traits>
 
 #include <folly/experimental/coro/Coroutine.h>
+#include <folly/experimental/coro/GtestHelpers.h>
 #include <folly/experimental/coro/Result.h>
 #include <folly/experimental/coro/Task.h>
 #include <folly/portability/GMock.h>
@@ -230,4 +231,8 @@ auto CoThrow(Ex&& e) {
 } // namespace coro
 } // namespace folly
 
+#define CO_ASSERT_THAT(value, matcher) \
+  CO_ASSERT_PRED_FORMAT1(              \
+      ::testing::internal::MakePredicateFormatterFromMatcher(matcher), value)
+
 #endif // FOLLY_HAS_COROUTINES

folly/experimental/coro/GtestHelpers.h

@@ -137,6 +137,9 @@
  */
 #define CO_GTEST_FATAL_FAILURE_(message) \
   co_return GTEST_MESSAGE_(message, ::testing::TestPartResult::kFatalFailure)
+
+#define CO_ASSERT_PRED_FORMAT1(pred_format, v1) \
+  GTEST_PRED_FORMAT1_(pred_format, v1, CO_GTEST_FATAL_FAILURE_)
 #define CO_ASSERT_PRED_FORMAT2(pred_format, v1, v2) \
   GTEST_PRED_FORMAT2_(pred_format, v1, v2, CO_GTEST_FATAL_FAILURE_)
 

folly/experimental/coro/test/GmockHelpersTest.cpp

@@ -23,6 +23,7 @@
 #include <gtest/gtest-death-test.h>
 
 #include <folly/experimental/coro/GmockHelpers.h>
+#include <folly/experimental/coro/GtestHelpers.h>
 
 #include <folly/experimental/coro/BlockingWait.h>
 #include <folly/experimental/coro/Task.h>
@@ -174,4 +175,8 @@ TEST(CoroLambdaGtest, CoThrowTest) {
   EXPECT_THROW(folly::coro::blockingWait(mock.getString()), std::runtime_error);
 }
 
+CO_TEST(CoAssertThat, CoAssertThat) {
+  CO_ASSERT_THAT(1, Gt(0));
+}
+
 #endif // FOLLY_HAS_COROUTINES