immutable-arguments(#989): add a first-class unit test (closes #989)

the functionality as such is already covered,
but it seems important enough to warrant a dedicated test.


incidentally, Duration still lacked a default ctor.
Time values are default constructible, yet immutable.

src/lib/time/timevalue.hpp

@@ -384,6 +384,10 @@ namespace time {
       Duration& operator= (Duration const&);
       
     public:
+      Duration()
+        : Duration(Time::ZERO)
+        { }
+      
       Duration (Offset const& distance)
         : TimeValue(distance.abs())
         { }

tests/45controller.tests

@@ -45,6 +45,11 @@ return: 0
 END
 
 
+TEST "argument binding from GenNode message" CommandMessageBinding_test <<END
+return: 0
+END
+
+
 TEST "Command functor and UNDO functor" CommandMutation_test <<END
 out-lit: empty placeholder closure: Command-Closure{ arguments=unbound }
 out-lit: param values: Command-Closure{ arguments=OpClosure(23) }

tests/core/proc/control/command-message-binding-test.cpp

@@ -0,0 +1,130 @@
+/*
+  CommandMessageBinding(Test)  -  verify argument binding via GenNode-Message, with immutable types
+
+  Copyright (C)         Lumiera.org
+    2016,               Hermann Vosseler <Ichthyostega@web.de>
+
+  This program is free software; you can redistribute it and/or
+  modify it under the terms of the GNU General Public License as
+  published by the Free Software Foundation; either version 2 of
+  the License, or (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+* *****************************************************/
+
+
+#include "lib/test/run.hpp"
+#include "lib/test/test-helper.hpp"
+#include "proc/control/command-def.hpp"
+#include "lib/time/timevalue.hpp"
+#include "lib/diff/gen-node.hpp"
+
+
+namespace proc {
+namespace control {
+namespace test    {
+  
+  using lib::time::Time;
+  using lib::time::TimeVar;
+  using lib::time::TimeValue;
+  using lib::time::TimeSpan;
+  using lib::time::Duration;
+  using lib::test::randTime;
+  using lib::diff::Rec;
+  
+  
+  
+  
+  
+  namespace  { // functions to be invoked through the command system
+    
+    TimeVar implicitTestState;
+    
+    void
+    operate (Duration dur)
+    {
+      implicitTestState += dur;
+    }
+    
+    TimeVar
+    capture (Duration)
+    {
+      return implicitTestState;
+    }
+    
+    void
+    undoIt (Duration, TimeVar oldVal)
+    {
+      implicitTestState = oldVal;
+    }
+  }
+  
+  
+  
+  
+  /***********************************************************************//**
+   * @test verify the simple standard usage pattern, where command arguments
+   *       for binding are passed via UI-Bus message with GenNode elements.
+   * This is a simplified demonstration, but covers some tricky aspects.
+   * - commands may define arguments of arbitrary type, and at runtime
+   *   these are initialised from the set of standard types allowed
+   *   within GenNode elements. Here the Duration is initialised from
+   *   a TimeSpan object
+   * - we support immutable argument types, which means the command binding
+   *   machinery works without (re)assignment, only copy construction of
+   *   argument holders into an inline buffer.
+   * 
+   * @see BusTerm_test
+   * @see TupleRecordInit_test
+   */
+  class CommandMessageBinding_test : public Test
+    {
+      
+      virtual void
+      run (Arg) 
+        {
+          Time five(TimeValue(5));
+          implicitTestState = five;
+          
+          CommandDef ("test.command2")
+              .operation (operate)
+              .captureUndo (capture)
+              .undoOperation (undoIt)
+              ;
+          
+          
+          
+          TimeSpan testSpan (randTime(), randTime());
+          Rec argMsg {testSpan};
+          
+          // bind the command argument from a GenNode message
+          Command ourCmd = Command::get("test.command2");
+          CHECK (not ourCmd.canExec());
+          
+          ourCmd.bindArg (argMsg);
+          CHECK (ourCmd.canExec());
+          
+          // invoke the command
+          ourCmd();
+          CHECK (implicitTestState == five + Duration(testSpan));
+          
+          // undo the effect of the command
+          ourCmd.undo();
+          CHECK (implicitTestState == five);
+        }
+    };
+  
+  
+  /** Register this test class... */
+  LAUNCHER (CommandMessageBinding_test, "unit controller");
+  
+  
+}}} // namespace proc::control::test