raw_ostream: add operator<< overload for std::error_code

Summary:
The main motivation for this is unit tests, which contain a large macro
for pretty-printing std::error_code, and this macro is duplicated in
every file that needs to do this. However, the functionality may be
useful elsewhere too.

In this patch I have reimplemented the existing ASSERT_NO_ERROR macros
to reuse the new functionality, but I have kept the macro (as a
one-liner) as it is slightly more readable than ASSERT_EQ(...,
std::error_code()).

Reviewers: sammccall, ilya-biryukov

Subscribers: zturner, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65643

llvm-svn: 368849

1 files changed, 8 insertions, 1 deletions

diff --git a/llvm/unittests/Support/ErrorTest.cpp b/llvm/unittests/Support/ErrorTest.cpp
index c4a9f3e..ec5c30b5 100644
--- a/llvm/unittests/Support/ErrorTest.cpp
+++ b/llvm/unittests/Support/ErrorTest.cpp
@@ -933,7 +933,7 @@ public:
 
 class TestErrorCategory : public std::error_category {
 public:
-  const char *name() const noexcept override { return "error"; }
+  const char *name() const noexcept override { return "test_error"; }
   std::string message(int Condition) const override {
     switch (static_cast<test_error_code>(Condition)) {
     case test_error_code::unspecified:
@@ -975,4 +975,11 @@ TEST(Error, SubtypeStringErrorTest) {
             0);
 }
 
+TEST(Error, error_codeErrorMessageTest) {
+  EXPECT_NONFATAL_FAILURE(
+      EXPECT_EQ(make_error_code(test_error_code::unspecified),
+                make_error_code(test_error_code::error_2)),
+      "Which is: An unknown error has occurred. (test_error:1)");
+}
+
 } // namespace