[Support] Add conversions between Expected<T> and ErrorOr<T>.

More utilities to help with std::error_code -> Error transitions.

llvm-svn: 264238

1 files changed, 24 insertions, 1 deletions

diff --git a/llvm/unittests/Support/ErrorTest.cpp b/llvm/unittests/Support/ErrorTest.cpp
index 1807547..fadb00c 100644
--- a/llvm/unittests/Support/ErrorTest.cpp
+++ b/llvm/unittests/Support/ErrorTest.cpp
@@ -416,7 +416,7 @@ TEST(Error, ExpectedCovariance) {
   A2 = Expected<std::unique_ptr<D>>(nullptr);
 }
 
-TEST(Error, ECError) {
+TEST(Error, ErrorCodeConversions) {
   // Round-trip a success value to check that it converts correctly.
   EXPECT_EQ(errorToErrorCode(errorCodeToError(std::error_code())),
             std::error_code())
@@ -427,6 +427,29 @@ TEST(Error, ECError) {
             errc::invalid_argument)
       << "std::error_code error value should round-trip via Error "
          "conversions";
+
+  // Round-trip a success value through ErrorOr/Expected to check that it
+  // converts correctly.
+  {
+    auto Orig = ErrorOr<int>(42);
+    auto RoundTripped =
+      expectedToErrorOr(errorOrToExpected(ErrorOr<int>(42)));
+    EXPECT_EQ(*Orig, *RoundTripped)
+      << "ErrorOr<T> success value should round-trip via Expected<T> "
+         "conversions.";
+  }
+
+  // Round-trip a failure value through ErrorOr/Expected to check that it
+  // converts correctly.
+  {
+    auto Orig = ErrorOr<int>(errc::invalid_argument);
+    auto RoundTripped =
+      expectedToErrorOr(
+          errorOrToExpected(ErrorOr<int>(errc::invalid_argument)));
+    EXPECT_EQ(Orig.getError(), RoundTripped.getError())
+      << "ErrorOr<T> failure value should round-trip via Expected<T> "
+         "conversions.";
+  }
 }
 
 } // end anon namespace