Evaluate EXPECT_STD* output argument once.

test/gtest-extra-test.cc

@@ -109,6 +109,13 @@ TEST_F(SingleEvaluationTest, FailedEXPECT_THROW_MSG) {
   EXPECT_EQ(s_ + 1, p_);
 }
 
+// Tests that when EXPECT_STDOUT fails, it evaluates its message argument
+// exactly once.
+TEST_F(SingleEvaluationTest, FailedEXPECT_STDOUT) {
+  EXPECT_NONFATAL_FAILURE(EXPECT_STDOUT(std::printf("test"), p_++), "01234");
+  EXPECT_EQ(s_ + 1, p_);
+}
+
 // Tests that assertion arguments are evaluated exactly once.
 TEST_F(SingleEvaluationTest, ExceptionTests) {
   // successful EXPECT_THROW_MSG

test/gtest-extra.h

@@ -44,16 +44,16 @@
 #define FMT_TEST_THROW_(statement, expected_exception, expected_message, fail) \
   GTEST_AMBIGUOUS_ELSE_BLOCKER_ \
   if (::testing::AssertionResult gtest_ar = ::testing::AssertionSuccess()) { \
-    std::string expected_message_str = expected_message; \
+    std::string gtest_expected_message = expected_message; \
     bool gtest_caught_expected = false; \
     try { \
       GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement); \
     } \
     catch (expected_exception const& e) { \
-      if (expected_message_str != e.what()) { \
+      if (gtest_expected_message != e.what()) { \
         gtest_ar \
           << #statement " throws an exception with a different message.\n" \
-          << "Expected: " << expected_message_str << "\n" \
+          << "Expected: " << gtest_expected_message << "\n" \
           << "  Actual: " << e.what(); \
         goto GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__); \
       } \
@@ -340,16 +340,14 @@ class OutputRedirect {
 #define FMT_TEST_PRINT_(statement, expected_output, file, fail) \
   GTEST_AMBIGUOUS_ELSE_BLOCKER_ \
   if (::testing::AssertionResult gtest_ar = ::testing::AssertionSuccess()) { \
-    std::string gtest_output; \
-    { \
+    std::string gtest_expected_output = expected_output; \
     OutputRedirect gtest_redir(file); \
     GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement); \
-      gtest_output = gtest_redir.RestoreAndRead(); \
-    } \
-    if (gtest_output != expected_output) { \
+    std::string gtest_output = gtest_redir.RestoreAndRead(); \
+    if (gtest_output != gtest_expected_output) { \
       gtest_ar \
         << #statement " produces different output.\n" \
-        << "Expected: " << expected_output << "\n" \
+        << "Expected: " << gtest_expected_output << "\n" \
         << "  Actual: " << gtest_output; \
       goto GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__); \
     } \