diff --git a/tests/20plugin.tests b/tests/20plugin.tests
index 51ea85370..6e8cd96de 100644
--- a/tests/20plugin.tests
+++ b/tests/20plugin.tests
@@ -1,5 +1,24 @@
 TESTING "test plugin example code" ./test-plugin
 
-TEST "plugin example" <<END
+TEST "C plugin example" C <<END
+out: opened
+out: Hallo Welt!
+out: Tschuess C
+out: opened
+out: Hello World!
+out: Bye C
+out: closed
+out: closed
+END
+
+TEST "C++ plugin example" C++ <<END
+out: opened
+out: Hallo Welt!
+out: Tschuess C++
+out: opened
+out: Hello World!
+out: Bye C++
+out: closed
+out: closed
 END
 
diff --git a/tests/plugin/example_plugin.c b/tests/plugin/example_plugin.c
index 5cd035bf2..ebb71ae8a 100644
--- a/tests/plugin/example_plugin.c
+++ b/tests/plugin/example_plugin.c
@@ -21,17 +21,17 @@ void hallo(void)
 
 void tschuess(const char* m)
 {
-  printf("Tschues %s\n", m);
+  printf("Tschuess %s\n", m);
 }
 
 void hello(void)
 {
-  printf("Hello world!\n");
+  printf("Hello World!\n");
 }
 
 void bye(const char* m)
 {
-  printf("bye %s\n", m);
+  printf("Bye %s\n", m);
 }
 
 CINELERRA_INTERFACE_IMPLEMENT(hello, 1, german, myopen, myclose,
diff --git a/tests/plugin/plugin_main.c b/tests/plugin/plugin_main.c
index b71a63167..e81c0724b 100644
--- a/tests/plugin/plugin_main.c
+++ b/tests/plugin/plugin_main.c
@@ -1,4 +1,4 @@
-
+#include <string.h>
 
 #include "lib/plugin.h"
 #include "hello_interface.h"
@@ -9,6 +9,9 @@ main(int argc, char** argv)
 {
   NOBUG_INIT;
 
+  if (argc < 2)
+    return -1;
+
   cinelerra_init_plugin ();
   /*
     we have a plugin 'hello_1' which provides us 2 hello interfaces, one for english and one for german output,
@@ -17,24 +20,31 @@ main(int argc, char** argv)
 
   TODO("macros, doing casting and typing");
 
-  CINELERRA_INTERFACE_TYPE(hello, 1)* hello_de =
-    (CINELERRA_INTERFACE_TYPE(hello, 1)*) cinelerra_interface_open ("example_plugin", "german_1", sizeof(CINELERRA_INTERFACE_TYPE(hello, 1)));
+  if( !strcmp(argv[1],"C"))
+    {
 
-  if (!hello_de) CINELERRA_DIE;
+      CINELERRA_INTERFACE_TYPE(hello, 1)* hello_de =
+        (CINELERRA_INTERFACE_TYPE(hello, 1)*) cinelerra_interface_open ("example_plugin", "german_1", sizeof(CINELERRA_INTERFACE_TYPE(hello, 1)));
 
-  hello_de->hello();
+      if (!hello_de) CINELERRA_DIE;
 
+      hello_de->hello();
+      hello_de->goodbye(argv[1]);
 
-  CINELERRA_INTERFACE_TYPE(hello, 1)* hello_en =
-    (CINELERRA_INTERFACE_TYPE(hello, 1)*) cinelerra_interface_open ("example_plugin", "english_1", sizeof(CINELERRA_INTERFACE_TYPE(hello, 1)));
+      CINELERRA_INTERFACE_TYPE(hello, 1)* hello_en =
+        (CINELERRA_INTERFACE_TYPE(hello, 1)*) cinelerra_interface_open ("example_plugin", "english_1", sizeof(CINELERRA_INTERFACE_TYPE(hello, 1)));
 
-  if (!hello_en) CINELERRA_DIE;
+      if (!hello_en) CINELERRA_DIE;
 
-  hello_en->hello();
+      hello_en->hello();
+      hello_en->goodbye(argv[1]);
 
-  cinelerra_interface_close (hello_en);
-  cinelerra_interface_close (hello_de);
+      cinelerra_interface_close (hello_en);
+      cinelerra_interface_close (hello_de);
+    }
 
+  if( !strcmp(argv[1],"C++"))
+    {
 #if 0
   /*
     same again for a plugin written in C++
@@ -44,6 +54,7 @@ main(int argc, char** argv)
   if (!hello_de) CINELERRA_DIE;
 
   hello_de->say_hello();
+  hello_de->say_hello();
 
 
   hello_en =
@@ -55,6 +66,7 @@ main(int argc, char** argv)
   cinelerra_interface_close (hello_en);
   cinelerra_interface_close (hello_de);
 #endif
+    }
 
   return 0;
 }