[PATCH] D105014: added some example code for llvm::Expected<T>

[Christian Kühnel via Phabricator via cfe-commits]

kuhnel updated this revision to Diff 355507.
kuhnel marked 4 inline comments as done.
kuhnel added a comment.

updated code examples based on Sam's review

Oh my, this is really simple if you know how it's supposed 
to work. However my intuition is completely off in trying to
understand the error handling. I hope the examples help
others avoid the pain.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D105014/new/

https://reviews.llvm.org/D105014

Files:
  llvm/include/llvm/Testing/Support/Error.h


Index: llvm/include/llvm/Testing/Support/Error.h
===================================================================
--- llvm/include/llvm/Testing/Support/Error.h
+++ llvm/include/llvm/Testing/Support/Error.h
@@ -165,26 +165,24 @@
 #define ASSERT_THAT_ERROR(Err, Matcher)                                        \
   ASSERT_THAT(llvm::detail::TakeError(Err), Matcher)
 
-/// Helper marcro for checking the result of an 'Expected<T>'
+/// Helper macro for checking the result of an 'Expected<T>'
 ///
 ///   @code{.cpp}
 ///     // function to be tested
 ///     Expected<int> myDivide(int A, int B);
 ///
 ///     TEST(myDivideTests, GoodAndBad) {
-///       // test the good care
-///       auto D1 = myDivide(10, 5);
-///       // ensure the Error gets consumed in case the function fails by
-///       // calling 'toString()'. This also helps in debugging failing tests.
-///       EXPECT_THAT_EXPECTED(D1, Succeeded()) << toString(D1.takeError()) <<
-///         "\n";
-///       EXPECT_THAT(*D1, Eq(2));
+///       // test good case
+///       // if you only care about successor failure:
+///       EXPECT_THAT_EXPECTED(myDivide(10, 5), Succeeded());
+///       // if you also care about the value:
+///       EXPECT_THAT_EXPECTED(myDivide(10, 5), HasValue(2));
 ///
 ///       // test the error case
-///       auto D2 = myDivide(10, 0);
-///       EXPECT_THAT_EXPECTED(D2, Failed());
-///       // In the error case we need to consume the error.
-///       consumeError(D2.takeError());
+///       EXPECT_THAT_EXPECTED(myDivide(10, 0), Failed());
+///       // also check the error message
+///       EXPECT_THAT_EXPECTED(myDivide(10, 0),
+///           FailedWithMessage("B must not be zero!"));
 ///     }
 ///   @endcode
 


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