diff --git a/application/argumentparser.cpp b/application/argumentparser.cpp
index d135e7a..3e6e438 100644
--- a/application/argumentparser.cpp
+++ b/application/argumentparser.cpp
@@ -251,7 +251,7 @@ void ArgumentReader::read(ArgumentVector &args)
                         ++index, ++argv, argDenotation = nullptr;
                         break;
                     case UnknownArgumentBehavior::Fail:
-                        throw Failure("The specified argument \""s % *argv + "\" is unknown and will be ignored."s);
+                        throw Failure(argsToString("The specified argument \"", *argv, "\" is unknown."));
                     }
                 }
             } // if(!matchingArg)
diff --git a/tests/argumentparsertests.cpp b/tests/argumentparsertests.cpp
index 194a166..58ab88c 100644
--- a/tests/argumentparsertests.cpp
+++ b/tests/argumentparsertests.cpp
@@ -169,7 +169,7 @@ void ArgumentParserTests::testParsing()
         parser.parseArgs(6, argv3);
         CPPUNIT_FAIL("Exception expected.");
     } catch(const Failure &e) {
-        CPPUNIT_ASSERT(!strcmp(e.what(), "The specified argument \"album\" is unknown and will be ignored."));
+        CPPUNIT_ASSERT_EQUAL("The specified argument \"album\" is unknown."s, string(e.what()));
     }
 
     // warning about unknown argument
@@ -272,7 +272,7 @@ void ArgumentParserTests::testParsing()
         CPPUNIT_FAIL("Exception expected.");
     } catch(const Failure &e) {
         CPPUNIT_ASSERT(!qtConfigArgs.qtWidgetsGuiArg().isPresent());
-        CPPUNIT_ASSERT(!strcmp(e.what(), "The specified argument \"-f\" is unknown and will be ignored."));
+        CPPUNIT_ASSERT_EQUAL("The specified argument \"-f\" is unknown."s, string(e.what()));
     }
 
     // equation sign syntax