Remove test-artifact from user visible part of how_to_invoke_a_functor_passed_as_parameter_of_a_mock_method

Only show what is required

doc/example/patterns_invoke_functor.cpp

@@ -6,6 +6,10 @@
 // (See accompanying file LICENSE_1_0.txt or copy at
 // http://www.boost.org/LICENSE_1_0.txt)
 
+// Intentionally duplicate to have complete examples and minimal user visible, yet tested test code
+#include <boost/test/unit_test.hpp>
+
+static void someFunctor(int newValue);
 //[ invoke_functor_problem
 #include <functional>
 
@@ -15,21 +19,27 @@
         virtual void method( const std::function< void( int ) >& functor ) = 0;
     };
 
-    void function( base_class& ); // the function will call 'method' with a functor to be applied
+    // the function will call 'method' with a functor to be applied
+    void function(base_class& c) { c.method(someFunctor); } 
 //]
 
-namespace
-{
-    int receivedValue = 0;
-    void setValue(int newValue)
+// Some test-only code to verify what is described
+static int receivedValue = 0;
+static void someFunctor(int newValue)
 {
     receivedValue = newValue;
 }
-}
-void function( base_class& c)
+// Check that the functor was called with 42
+struct CheckReceivedValue
 {
-    c.method(setValue);
+    void teardown()
+    {
+        BOOST_CHECK(receivedValue == 42); // functor was called and received the value 42
     }
+};
+// And force using it w/o showing that in the docs
+#undef BOOST_AUTO_TEST_CASE
+#define BOOST_AUTO_TEST_CASE(name) BOOST_FIXTURE_TEST_CASE(name, CheckReceivedValue)
 
 //[ invoke_functor_solution
 #include <boost/test/unit_test.hpp>
@@ -48,6 +58,5 @@ BOOST_AUTO_TEST_CASE( how_to_invoke_a_functor_passed_as_parameter_of_a_mock_meth
     mock_class mock;
     MOCK_EXPECT( mock.method ).calls( [](const auto &functor){ functor(42); } ); // whenever 'method' is called, invoke the functor with 42
     function( mock );
-    BOOST_CHECK(receivedValue == 42); // functor was called and received the value 42
 }
 //]