Add guards against exceptions that shouldn't happen

I'm getting a couple of "terminate called after throwing an instance of
'test::lightweight::test_exception'" errors on the sun platform. Not
sure where they're happening, so I've made the code a tad more resilient
against exceptions that should not really be thrown.

test/helpers/exception_test.hpp

@@ -179,12 +179,13 @@ namespace test {
     class test_runner
     {
         Test const& test_;
+        bool exception_in_check_;
 
         test_runner(test_runner const&);
         test_runner& operator=(test_runner const&);
     public:
-        test_runner(Test const& t) : test_(t) {}
+        test_runner(Test const& t) : test_(t), exception_in_check_(false) {}
-        void operator()() const {
+        void run() {
             DISABLE_EXCEPTIONS;
             test::scope = "";
             BOOST_DEDUCED_TYPENAME Test::data_type x(test_.init());
@@ -199,14 +200,24 @@ namespace test {
                 >(&Test::run, test_, x, strong);
             }
             catch(...) {
-                call_ignore_extra_parameters<
+                try {
-                    Test,
+                    DISABLE_EXCEPTIONS;
-                    BOOST_DEDUCED_TYPENAME Test::data_type const,
+                    call_ignore_extra_parameters<
-                    BOOST_DEDUCED_TYPENAME Test::strong_type const
+                        Test,
-                >(&Test::check, test_, constant(x), constant(strong));
+                        BOOST_DEDUCED_TYPENAME Test::data_type const,
+                        BOOST_DEDUCED_TYPENAME Test::strong_type const
+                    >(&Test::check, test_, constant(x), constant(strong));
+                } catch(...) {
+                    exception_in_check_ = true;
+                }
                 throw;
             }
         }
+        void end() {
+            if (exception_in_check_) {
+                BOOST_ERROR("Unexcpected exception in test_runner check call.");
+            }
+        }
     };
 
     // Quick exception testing based on lightweight test
@@ -236,26 +247,30 @@ namespace test {
 
             iteration = 0;
             bool success = false;
+            char const* error_msg = 0;
             do {
                 ++iteration;
                 count = 0;
 
                 try {
-                    runner();
+                    runner.run();
                     success = true;
                 }
                 catch(test_failure) {
-                    BOOST_ERROR("test_failure caught.");
+                    error_msg = "test_failure caught.";
                     break;
                 }
                 catch(test_exception) {
                     continue;
                 }
                 catch(...) {
-                    BOOST_ERROR("Unexpected exception.");
+                    error_msg = "Unexpected exception.";
                     break;
                 }
             } while(!success);
+
+            if (error_msg) { BOOST_ERROR(error_msg); }
+            runner.end();
         }
     }
 }