diff --git a/src/common/streamtype.hpp b/src/common/streamtype.hpp
index 28c87bfa4..4f79969d7 100644
--- a/src/common/streamtype.hpp
+++ b/src/common/streamtype.hpp
@@ -71,7 +71,7 @@ namespace lumiera {
       
       
       Prototype const& prototype;
-      ImplFacade * implType;
+      ImplFacade * implType;       /////////////TODO: really by ptr???
       Usage intentionTag;
       
     };
diff --git a/tests/common/streamtypebasicstest.cpp b/tests/common/streamtypebasicstest.cpp
index 6097da0a7..a2c1332d0 100644
--- a/tests/common/streamtypebasicstest.cpp
+++ b/tests/common/streamtypebasicstest.cpp
@@ -29,13 +29,15 @@
 
 #include <iostream>
 using std::cout;
-
+using ::test::Test;
+using util::isnil;
 
 
 namespace lumiera {
   namespace test_format {
     
     using control::STypeManager;
+    typedef StreamType const& SType;
     typedef StreamType::ImplFacade const& ImplType;
     
     
@@ -47,13 +49,18 @@ namespace lumiera {
      */
     class StreamTypeBasics_test : public Test
       {
-        virtual void run (Arg arg)
+        virtual void
+        run (Arg arg)
           {
-            buildImplType ();
-            basicImplTypeProperties ();
+            ImplType iType = buildImplType ();
+            basicImplTypeProperties (iType);
+            
+            SType type = extend2fullType (iType);
+            basicStreamTypeProperties (type, iType);
           }
         
-        void buildImplType ()
+        ImplType
+        buildImplType ()
           {
             STypeManager& typeManager = STypeManager::instance();
         
@@ -64,16 +71,45 @@ namespace lumiera {
             
             TODO ("how to do a simple consistency check on the returned ImplFacade? can we re-create the GAVL frame type?");
             ASSERT (GAVL==iTy.libraryID);
+            return iTy;
           }
         
-        void basicImplTypeProperties ()
+        void
+        basicImplTypeProperties (ImplType refType)
           {
-            ImplType iTy = test_createImplType ();
+            ImplType iTy2 = test_createImplType ();
+            ASSERT (iTy2==refType);
+            ASSERT (refType==iTy2);
+            TODO ("add equality comparable concept to the ImplType class");
             
+            ASSERT (StreamType::VIDEO==refType.getKind());
             UNIMPLEMENTED ("get a lib descriptor"); 
             UNIMPLEMENTED ("check the lib of the type"); 
             UNIMPLEMENTED ("compare two types"); 
           }
+        
+        SType
+        extend2fullType (ImplType iTy)
+          {
+            return STypeManager::instance().getType(iTy);
+          }
+        
+        void
+        basicStreamTypeProperties (SType type, ImplType iTy)
+          {
+            ASSERT (type.implType);
+            ASSERT (iTy==(*type.implType));  /////////////TODO: really by ptr???
+            ASSERT (&iTy==type.implType);   // actually using the same object (in the registry)
+            
+            ASSERT (!isnil (type.prototype.id));
+            ASSERT (StreamType::VIDEO==type.prototype.kind);
+            ASSERT (StreamType::VIDEO==type.implType->getKind());
+            
+            ASSERT (type.implType->canConvert(iTy));  // of course... they are actually the same
+            ASSERT (iTy.canConvert(type));           // because it's based on the same impl type
+            
+            ASSERT (StreamType::RAW==type.intentionTag);
+          }
       };
     
     LAUNCHER (StreamTypeBasics_test, "unit common");
diff --git a/wiki/renderengine.html b/wiki/renderengine.html
index 624a36e3a..bb22c2320 100644
--- a/wiki/renderengine.html
+++ b/wiki/renderengine.html
@@ -3431,7 +3431,7 @@ An implementation constraint can //stand-in// for a completely specified impleme
 //Note:// there is a sort-of &quot;degraded&quot; variant just requiring some &amp;rarr; [[implementation constraint|StreamTypeImplConstraint]] to hold
 </pre>
 </div>
-<div title="StreamTypeQuery" modifier="Ichthyostega" modified="200810020327" created="200809280129" tags="spec draft" changecount="22">
+<div title="StreamTypeQuery" modifier="Ichthyostega" modified="200810060525" created="200809280129" tags="spec draft" changecount="23">
 <pre>Querying for media stream type information comes in various flavours
 * you may want to find a structural object (pipe, output, processing patten) associated with / able to deal with a certain stream type
 * you may need a StreamTypeDescriptor for an existing stream given as implementation data
@@ -3471,9 +3471,10 @@ Essentially, we need a search mechanism for impltypes and prototypes. This searc
 
 !query for an (complete) StreamType
 All situations discussed thus far can also occur wrapped into and triggered by a query for a complete type. Depending on what part is known, the missing bits will be queried. 
-Independent from these is another __Situation__ where we query for a type ''by ID''.
+Independent from these is __another Situation__ where we query for a type ''by ID''.
 * a simple symbolic ID can be found by searching through all existing stream types (Operation supported by the type registry within STypeManager)
 * a special ''classificating'' ID can be parsed into the components (media kind, prototype, impltype), resulting in sub searches for these.
+{{red{not sure if we want to support queries by symboic ID}}}...problem is the impl type, because probably the library needs to support describing any implementation type by a string. Seemingly GAVL does, but requiring it for every lib?
 </pre>
 </div>
 <div title="StreamTypeUse" modifier="Ichthyostega" modified="200809280320" created="200809130312" tags="draft discuss dynamic" changecount="21">