Merge pull request #48 from deivid-rodriguez/fix_2_4_ci

Fix Ruby 2.4 test run

Author: hsbt

test/lib/core_assertions.rb

@@ -213,7 +213,7 @@ def assert_raise(*exp, &b)
           }
 
           assert expected, proc {
-            exception_details(e, message(msg) {"#{mu_pp(exp)} exception expected, not"}.call)
+            flunk(message(msg) {"#{mu_pp(exp)} exception expected, not #{mu_pp(e)}"})
           }
 
           return e
@@ -378,7 +378,7 @@ def assert_join_threads(threads, message = nil)
           msg = "exceptions on #{errs.length} threads:\n" +
             errs.map {|t, err|
             "#{t.inspect}:\n" +
-              err.full_message(highlight: false, order: :top)
+              RUBY_VERSION >= "2.5.0" ? err.full_message(highlight: false, order: :top) : err.message
           }.join("\n---\n")
           if message
             msg = "#{message}\n#{msg}"