add MessageMatches matcher

[lbckmnn]

Description

If you want to test whether a function throws an exception with a message, it is currently not possible to check the exception type and apply a matcher on the exception message in one run. You can check the exact message with REQUIRE_THROWS_MATCHES and Message("test") but you can not apply a matcher on the message.

If you want to apply a matcher on the exception message and check the type, the current options are:

1. check type and message in two runs:

//REQUIRE_THROWS_WITH allows to apply a matcher on the message but doesn't allow checking the type
REQUIRE_THROWS_WITH(throwsException(),  StartsWith("Argument is invalid")); 
//REQUIRE_THROWS_AS allows checking the type, but not the message
REQUIRE_THROWS_AS(throwsException(), std::invalid_argument); 

2. use REQUIRE_THROWS_MATCHES:
   This options only allows applying matchers on the exception itself, and not on the message so you have to write a custom matcher.

This PR adds a matcher that makes it possible to use std::string matchers like StartsWith or ContainsSubstring on exception messages together with REQUIRE_THROWS_MATCHES.

Example:

REQUIRE_THROWS_MATCHES(throwsException(),  std::runtime_error,  MessageMatches(StartsWith("Argument is invalid")));

[codecov]

Codecov Report

Merging #2570 (fd2188c) into devel (2d7be1f) will increase coverage by 0.01%.
The diff coverage is 100.00%.

❗ Current head fd2188c differs from pull request most recent head 4ec135a. Consider uploading reports for the commit 4ec135a to get more accurate results

@@            Coverage Diff             @@
##            devel    #2570      +/-   ##
==========================================
+ Coverage   91.09%   91.10%   +0.01%     
==========================================
  Files         187      187              
  Lines        7622     7632      +10     
==========================================
+ Hits         6943     6953      +10     
  Misses        679      679              

[horenmar]

FYI: I like the addition, but won't get to this until late next week.