From 059dbd8c75146ce44e5e39bcf65a80efc5a918e5 Mon Sep 17 00:00:00 2001
From: Ichthyostega <prg@ichthyostega.de>
Date: Tue, 23 Sep 2014 03:36:51 +0200
Subject: [PATCH] fix and finish the diagnostics helper

there was still a subtle bug in this helper.
testing your own test fixture is sometimes a good idea ;-)
---
 src/lib/test/test-helper.hpp                  | 14 +++++++---
 tests/40core.tests                            | 27 +++++++++++++++++++
 .../test/test-helper-variadic-test.cpp        | 25 +++++++++--------
 3 files changed, 50 insertions(+), 16 deletions(-)

diff --git a/src/lib/test/test-helper.hpp b/src/lib/test/test-helper.hpp
index 3d0332c3f..425fc8429 100644
--- a/src/lib/test/test-helper.hpp
+++ b/src/lib/test/test-helper.hpp
@@ -112,7 +112,14 @@ namespace test{
                                                    : "VAL";
   }
   
-  /** helper for investigating a variadic argument pack */
+  /** helper for investigating a variadic argument pack
+   * @warning always spell out the template arguments explicitly
+   *          when invoking this diagnostics, e.g. \c showVariadicTypes<ARGS...>(args...)
+   *          otherwise the template argument matching for functions might mess up the
+   *          kind of reference you'll see in the diagnostics.
+   * @see test-helper-variadic-test.cpp
+   */
+  template<typename... EMPTY>
   inline string
   showVariadicTypes ()
   {
@@ -120,7 +127,7 @@ namespace test{
   }
   
   template<typename X, typename... XS>
-  string
+  inline string
   showVariadicTypes (X const& x, XS const&... xs)
   {
     return " :---#"
@@ -129,12 +136,13 @@ namespace test{
          + "  "          + showRefKind<X>()
          + "  Address* " + boost::lexical_cast<string>(&x)
          + "\n"
-         + showVariadicTypes (xs...);
+         + showVariadicTypes<XS...> (xs...);
   }
   
   
   
   
+  
   /** create a random but not insane Time value */
   inline lib::time::Time
   randTime ()
diff --git a/tests/40core.tests b/tests/40core.tests
index e0a71338c..e70b53f74 100644
--- a/tests/40core.tests
+++ b/tests/40core.tests
@@ -822,6 +822,33 @@ out: sizeof.+lib.+test.+test.+Wrmrmpft.+Murpf.+ =   1
 END
 
 
+TEST "Variadic template diagnostics" TestHelperVariadic_test <<END
+out-lit: --no-arg--
+out-lit:  :.
+out-lit: --value--
+out: .+#1.+ Type: d  VAL  Address. 0x.+
+out-lit:  :.
+out-lit: --reference--
+out: .+#1.+ Type: d  REF  Address. 0x.+
+out-lit:  :.
+out-lit: --move--
+out: .+#1.+ Type: d  MOV  Address. 0x.+
+out-lit:  :.
+out-lit: --two values--
+out: .+#2.+ Type: A4_c  REF  Address. 0x.+
+out: .+#1.+ Type: l  MOV  Address. 0x.+
+out-lit:  :.
+out-lit: --matched--
+out: .+#3.+ Type: d  REF  Address. 0x.+
+out: .+#2.+ Type: d  REF  Address. 0x.+
+out: .+#1.+ Type: d  MOV  Address. 0x.+
+out-lit:  :.
+out-lit: --baseclass--
+out: .+#1.+ Type: .+lib.test.test.+Interface.  REF  Address. 0x.+
+out-lit:  :.
+END
+
+
 TEST "TestOption_test" TestOption_test <<END
 out: Testing invocation with cmdline: ...
 out: --> Testgroup=ALL
diff --git a/tests/library/test/test-helper-variadic-test.cpp b/tests/library/test/test-helper-variadic-test.cpp
index d171dcf4c..2997bb688 100644
--- a/tests/library/test/test-helper-variadic-test.cpp
+++ b/tests/library/test/test-helper-variadic-test.cpp
@@ -23,21 +23,15 @@
 
 #include "lib/test/run.hpp"
 #include "lib/test/test-helper.hpp"
-//#include "lib/util.hpp"
 
 
-//#include <boost/lexical_cast.hpp>
 #include <iostream>
 #include <utility>
 #include <string>
 #include <cmath>
-//#include <map>
 
-//using boost::lexical_cast;
-//using util::contains;
 using std::string;
 using std::cout;
-//using std::endl;
 
 
 namespace lib {
@@ -65,7 +59,7 @@ namespace test{
         string s_;
         
       public:
-        Impl(string ss ="IMP") : s_(ss) { }
+        Impl(string ss ="ZOMG") : s_(ss) { }
       };
     
     
@@ -106,28 +100,33 @@ namespace test{
         {
           double d = makeRvalue();
           double& dr = d;
-
+          
           Impl obj;
           Interface const& ref = obj;
-
+          
           cout << "--no-arg--\n" << showVariadicTypes() <<"\n";
           cout << "--value--\n"     << showVariadicTypes<double>(d) <<"\n";
           cout << "--reference--\n" << showVariadicTypes<double&>(d) <<"\n";
           cout << "--move--\n"      << showVariadicTypes<double&&>(d) <<"\n";
           
-          forwardFunction("two values", "foo", 42L);
-          forwardFunction("matched", d,dr,std::move(dr));
+          forwardFunction("two values", "foo", 42L);        // passed as REF, MOV
+          forwardFunction("matched", d,dr,std::move(dr));   // passed as REF, REF, MOV
           
           forwardFunction<Interface const&>("baseclass", ref);
         }
       
       
+      /** this dummy simulates a typical variadic call
+       *  which takes all arguments as '&&' for the purpose of "perfect forwarding"
+       */
       template<typename... ARGS>
       void
-      forwardFunction (string id, ARGS const&... args)
+      forwardFunction (string id, ARGS&&... args)
         {
+          // in reality here you'd invoke some factory(<std::forward<ARGS>(args)...)
+          //
           cout << "--"<<id<<"--\n"
-               << showVariadicTypes<ARGS...>(args...)
+               << showVariadicTypes<ARGS&&...>(args...)
                << "\n"
                ;
         }