test error handling of erroneous calls of initialize and finalize

test/c/interface_c.cpp

@@ -39,6 +39,28 @@ TEST(CInterfaceTest, JuliaProject) {
                            "this_string_is_just_way_toooooooooooooooooooo_long";
     EXPECT_DEATH( trixi_initialize( garbage, "/tmp" ),
                   "buffer size not sufficient for activation command");
+
+    // do not finalize before initialization
+    EXPECT_DEATH( trixi_finalize(),
+                  "trixi_initialize must be called before trixi_finalize");
+
+    // Initialize libtrixi
+    trixi_initialize( julia_project_path, NULL );
+
+    // do not initialize twice
+    EXPECT_DEATH( trixi_initialize( julia_project_path, NULL ),
+                  "trixi_initialize invoked multiple times");
+
+    // Finalize libtrixi
+    trixi_finalize();
+
+    // do not finalize twice
+    EXPECT_DEATH( trixi_finalize(),
+                  "trixi_finalize invoked multiple times");
+
+    // do not initialize after finalization
+    EXPECT_DEATH( trixi_initialize( julia_project_path, NULL ),
+                  "trixi_initialize invoked multiple times");
 }