[Testing/Support] Make the HasValue matcher composable

Summary:
This makes it possible to run an arbitrary matcher on the value
contained within the Expected<T> object.

To do this, I've needed to fully spell out the matcher, instead of using
the shorthand MATCHER_P macro.

The slight gotcha here is that standard template deduction will fail if
one tries to match HasValue(47) against an Expected<int &> -- the
workaround is to use HasValue(testing::Eq(47)).

The explanations produced by this matcher have changed a bit, since now
we delegate to the nested matcher to print the value. Since these don't
put quotes around the value, I've changed our PrintTo methods to match.

Reviewers: zturner

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D41065

llvm-svn: 320561

0 files changed, 0 insertions, 0 deletions