diff --git a/application/argumentparser.cpp b/application/argumentparser.cpp
index f2ba80d..da5f5ce 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 \"" % string(*argv) + "\" is unknown and will be ignored.");
+                        throw Failure("The specified argument \""s % *argv + "\" is unknown and will be ignored."s);
                     }
                 }
             } // if(!matchingArg)
@@ -1123,10 +1123,10 @@ void ArgumentParser::checkConstraints(const ArgumentVector &args)
     for(const Argument *arg : args) {
         const auto occurrences = arg->occurrences();
         if(arg->isParentPresent() && occurrences > arg->maxOccurrences()) {
-            throw Failure("The argument \"" % string(arg->name()) % "\" mustn't be specified more than " % arg->maxOccurrences() + (arg->maxOccurrences() == 1 ? " time." : " times."));
+            throw Failure("The argument \""s % arg->name() % "\" mustn't be specified more than "s % arg->maxOccurrences() + (arg->maxOccurrences() == 1 ? " time."s : " times."s));
         }
         if(arg->isParentPresent() && occurrences < arg->minOccurrences()) {
-            throw Failure("The argument \"" % string(arg->name()) % "\" must be specified at least " % arg->minOccurrences() + (arg->minOccurrences() == 1 ? " time." : " times."));
+            throw Failure("The argument \""s % arg->name() % "\" must be specified at least "s % arg->minOccurrences() + (arg->minOccurrences() == 1 ? " time."s : " times."s));
         }
         Argument *conflictingArgument = nullptr;
         if(arg->isMainArgument()) {
@@ -1137,7 +1137,7 @@ void ArgumentParser::checkConstraints(const ArgumentVector &args)
             conflictingArgument = arg->conflictsWithArgument();
         }
         if(conflictingArgument) {
-            throw Failure("The argument \"" % string(conflictingArgument->name()) % "\" can not be combined with \"" + arg->name() + "\".");
+            throw Failure("The argument \""s % conflictingArgument->name() % "\" can not be combined with \""s + arg->name() + "\"."s);
         }
         for(size_t i = 0; i != occurrences; ++i) {
             if(!arg->allRequiredValuesPresent(i)) {
diff --git a/chrono/datetime.cpp b/chrono/datetime.cpp
index 2f8f10b..a5cdce3 100644
--- a/chrono/datetime.cpp
+++ b/chrono/datetime.cpp
@@ -104,7 +104,7 @@ DateTime DateTime::fromString(const char *str)
         } else if(c == '\0') {
             break;
         } else {
-            throw ConversionException(string("unexpected ") + c);
+            throw ConversionException("unexpected "s + c);
         }
     }
     return DateTime::fromDateAndTime(values[0], values[1], *dayIndex, values[3], values[4], *secondsIndex, miliSeconds);
@@ -169,7 +169,7 @@ std::pair<DateTime, TimeSpan> DateTime::fromIsoString(const char *str)
         } else if(c == '\0') {
             break;
         } else {
-            throw ConversionException(string("unexpected \"") % c + '\"');
+            throw ConversionException("unexpected \""s % c + '\"');
         }
     }
     deltaNegative && (*deltaHourIndex = -*deltaHourIndex);
diff --git a/tests/argumentparsertests.cpp b/tests/argumentparsertests.cpp
index 214b5ac..194a166 100644
--- a/tests/argumentparsertests.cpp
+++ b/tests/argumentparsertests.cpp
@@ -185,11 +185,12 @@ void ArgumentParserTests::testParsing()
         throw;
     }
     cerr.rdbuf(regularCerrBuffer);
-    CPPUNIT_ASSERT(!strcmp(buffer.str().data(), "The specified argument \"album\" is unknown and will be ignored.\n"
-                                                "The specified argument \"title\" is unknown and will be ignored.\n"
-                                                "The specified argument \"diskpos\" is unknown and will be ignored.\n"
-                                                "The specified argument \"--files\" is unknown and will be ignored.\n"
-                                                "The specified argument \"somefile\" is unknown and will be ignored.\n"));
+    CPPUNIT_ASSERT_EQUAL("The specified argument \"album\" is unknown and will be ignored.\n"s
+                         "The specified argument \"title\" is unknown and will be ignored.\n"s
+                         "The specified argument \"diskpos\" is unknown and will be ignored.\n"s
+                         "The specified argument \"--files\" is unknown and will be ignored.\n"s
+                         "The specified argument \"somefile\" is unknown and will be ignored.\n"s,
+                         buffer.str());
     // none of the arguments should be present now
     CPPUNIT_ASSERT(!qtConfigArgs.qtWidgetsGuiArg().isPresent());
     CPPUNIT_ASSERT(!displayFileInfoArg.isPresent());
@@ -422,7 +423,7 @@ void ArgumentParserTests::testBashCompletion()
         reader.read();
         parser.printBashCompletion(1, argv1, 0, reader);
         cout.rdbuf(regularCoutBuffer);
-        CPPUNIT_ASSERT_EQUAL(string("COMPREPLY=()\n"), buffer.str());
+        CPPUNIT_ASSERT_EQUAL("COMPREPLY=()\n"s, buffer.str());
 
         // correct operation arg flags
         buffer.str(string());
@@ -431,7 +432,7 @@ void ArgumentParserTests::testBashCompletion()
         reader.reset(argv1, argv1 + 1).read();
         parser.printBashCompletion(1, argv1, 0, reader);
         cout.rdbuf(regularCoutBuffer);
-        CPPUNIT_ASSERT_EQUAL(string("COMPREPLY=('set' )\n"), buffer.str());
+        CPPUNIT_ASSERT_EQUAL("COMPREPLY=('set' )\n"s, buffer.str());
 
         // argument at current cursor position already specified -> the completion should just return the argument
         const char *const argv2[] = {"set"};
@@ -441,7 +442,7 @@ void ArgumentParserTests::testBashCompletion()
         reader.reset(argv2, argv2 + 1).read();
         parser.printBashCompletion(1, argv2, 0, reader);
         cout.rdbuf(regularCoutBuffer);
-        CPPUNIT_ASSERT_EQUAL(string("COMPREPLY=('set' )\n"), buffer.str());
+        CPPUNIT_ASSERT_EQUAL("COMPREPLY=('set' )\n"s, buffer.str());
 
         // advance the cursor position -> the completion should propose the next argument
         buffer.str(string());
@@ -450,7 +451,7 @@ void ArgumentParserTests::testBashCompletion()
         reader.reset(argv2, argv2 + 1).read();
         parser.printBashCompletion(1, argv2, 1, reader);
         cout.rdbuf(regularCoutBuffer);
-        CPPUNIT_ASSERT_EQUAL(string("COMPREPLY=('--files' '--values' )\n"), buffer.str());
+        CPPUNIT_ASSERT_EQUAL("COMPREPLY=('--files' '--values' )\n"s, buffer.str());
 
         // specifying no args should propose all main arguments
         buffer.str(string());
@@ -459,7 +460,7 @@ void ArgumentParserTests::testBashCompletion()
         reader.reset(nullptr, nullptr).read();
         parser.printBashCompletion(0, nullptr, 0, reader);
         cout.rdbuf(regularCoutBuffer);
-        CPPUNIT_ASSERT_EQUAL(string("COMPREPLY=('display-file-info' 'get' 'set' '--help' )\n"), buffer.str());
+        CPPUNIT_ASSERT_EQUAL("COMPREPLY=('display-file-info' 'get' 'set' '--help' )\n"s, buffer.str());
 
         // pre-defined values
         const char *const argv3[] = {"get", "--fields"};
@@ -469,7 +470,7 @@ void ArgumentParserTests::testBashCompletion()
         reader.reset(argv3, argv3 + 2).read();
         parser.printBashCompletion(2, argv3, 2, reader);
         cout.rdbuf(regularCoutBuffer);
-        CPPUNIT_ASSERT_EQUAL(string("COMPREPLY=('title' 'album' 'artist' 'trackpos' '--files' )\n"), buffer.str());
+        CPPUNIT_ASSERT_EQUAL("COMPREPLY=('title' 'album' 'artist' 'trackpos' '--files' )\n"s, buffer.str());
 
         // pre-defined values with equation sign, one letter already present
         const char *const argv4[] = {"set", "--values", "a"};
@@ -479,7 +480,7 @@ void ArgumentParserTests::testBashCompletion()
         reader.reset(argv4, argv4 + 3).read();
         parser.printBashCompletion(3, argv4, 2, reader);
         cout.rdbuf(regularCoutBuffer);
-        CPPUNIT_ASSERT_EQUAL(string("COMPREPLY=('album=' 'artist='  ); compopt -o nospace\n"), buffer.str());
+        CPPUNIT_ASSERT_EQUAL("COMPREPLY=('album=' 'artist='  ); compopt -o nospace\n"s, buffer.str());
 
         // file names
         string iniFilePath = TestUtilities::testFilePath("test.ini");
@@ -510,7 +511,7 @@ void ArgumentParserTests::testBashCompletion()
         reader.reset(argv6, argv6 + 2).read();
         parser.printBashCompletion(2, argv6, 1, reader);
         cout.rdbuf(regularCoutBuffer);
-        CPPUNIT_ASSERT_EQUAL(string("COMPREPLY=('--files' '--values' )\n"), buffer.str());
+        CPPUNIT_ASSERT_EQUAL("COMPREPLY=('--files' '--values' )\n"s, buffer.str());
 
         // nested sub arguments
         const char *const argv7[] = {"-i", "--sub", "--"};
@@ -520,7 +521,7 @@ void ArgumentParserTests::testBashCompletion()
         reader.reset(argv7, argv7 + 3).read();
         parser.printBashCompletion(3, argv7, 2, reader);
         cout.rdbuf(regularCoutBuffer);
-        CPPUNIT_ASSERT_EQUAL(string("COMPREPLY=('--files' '--nested-sub' '--verbose' )\n"), buffer.str());
+        CPPUNIT_ASSERT_EQUAL("COMPREPLY=('--files' '--nested-sub' '--verbose' )\n"s, buffer.str());
 
         // started pre-defined values with equation sign, one letter already present, last value matches
         const char *const argv8[] = {"set", "--values", "t"};
@@ -530,7 +531,7 @@ void ArgumentParserTests::testBashCompletion()
         reader.reset(argv8, argv8 + 3).read();
         parser.printBashCompletion(3, argv8, 2, reader);
         cout.rdbuf(regularCoutBuffer);
-        CPPUNIT_ASSERT_EQUAL(string("COMPREPLY=('title=' 'trackpos=' ); compopt -o nospace\n"), buffer.str());
+        CPPUNIT_ASSERT_EQUAL("COMPREPLY=('title=' 'trackpos=' ); compopt -o nospace\n"s, buffer.str());
 
         // combined abbreviations
         const char *const argv9[] = {"-gf"};
@@ -540,7 +541,7 @@ void ArgumentParserTests::testBashCompletion()
         reader.reset(argv9, argv9 + 1).read();
         parser.printBashCompletion(1, argv9, 0, reader);
         cout.rdbuf(regularCoutBuffer);
-        CPPUNIT_ASSERT_EQUAL(string("COMPREPLY=('-gf' )\n"), buffer.str());
+        CPPUNIT_ASSERT_EQUAL("COMPREPLY=('-gf' )\n"s, buffer.str());
 
         buffer.str(string());
         cout.rdbuf(buffer.rdbuf());
diff --git a/tests/chronotests.cpp b/tests/chronotests.cpp
index 3972f84..6031230 100644
--- a/tests/chronotests.cpp
+++ b/tests/chronotests.cpp
@@ -53,11 +53,11 @@ void ChronoTests::testDateTime()
     CPPUNIT_ASSERT(test1.dayOfWeek() == DayOfWeek::Wednesday);
     CPPUNIT_ASSERT_EQUAL((31 + 29), test1.dayOfYear());
     CPPUNIT_ASSERT(test1.isLeapYear());
-    CPPUNIT_ASSERT_EQUAL(string("Wed 2012-02-29 15:34:20.033"), test1.toString(DateTimeOutputFormat::DateTimeAndShortWeekday));
+    CPPUNIT_ASSERT_EQUAL("Wed 2012-02-29 15:34:20.033"s, test1.toString(DateTimeOutputFormat::DateTimeAndShortWeekday));
 
     // test fromTimeStamp()
     const auto test2 = DateTime::fromTimeStampGmt(1453840331);
-    CPPUNIT_ASSERT(test2.toString(DateTimeOutputFormat::DateTimeAndShortWeekday) == "Tue 2016-01-26 20:32:11");
+    CPPUNIT_ASSERT_EQUAL("Tue 2016-01-26 20:32:11"s, test2.toString(DateTimeOutputFormat::DateTimeAndShortWeekday));
 
     // test whether ConversionException() is thrown when invalid values are specified
     CPPUNIT_ASSERT_THROW(DateTime::fromDateAndTime(2013, 2, 29, 15, 34, 20, 33), ConversionException);
@@ -67,10 +67,10 @@ void ChronoTests::testDateTime()
 
     // test fromString()/toString()
     CPPUNIT_ASSERT_EQUAL(test1, DateTime::fromString("2012-02-29 15:34:20.033"));
-    CPPUNIT_ASSERT_EQUAL(string("2012-02-29 15:34:20.033"), test1.toString(DateTimeOutputFormat::DateAndTime, false));
+    CPPUNIT_ASSERT_EQUAL("2012-02-29 15:34:20.033"s, test1.toString(DateTimeOutputFormat::DateAndTime, false));
     CPPUNIT_ASSERT_THROW(TimeSpan::fromString("2012-02-29 15:34:34:20.033"), ConversionException);
     const auto test3 = DateTime::fromIsoString("2016-08-29T21:32:31.125+02:00");
-    CPPUNIT_ASSERT_EQUAL(string("2016-08-29T21:32:31.125+02:00"), test3.first.toIsoString(test3.second));
+    CPPUNIT_ASSERT_EQUAL("2016-08-29T21:32:31.125+02:00"s, test3.first.toIsoString(test3.second));
 }
 
 /*!
@@ -89,7 +89,7 @@ void ChronoTests::testTimeSpan()
     CPPUNIT_ASSERT(test1.totalDays() > 3.0 && test1.totalDays() < 4.0);
     CPPUNIT_ASSERT(test1.totalHours() > (2 * 24 + 34) && test1.totalHours() < (2 * 24 + 35));
     CPPUNIT_ASSERT(test1.totalMinutes() > (2 * 24 * 60 + 34 * 60 + 53) && test1.totalHours() < (2 * 24 * 60 + 34 * 60 + 54));
-    CPPUNIT_ASSERT(test1.toString(TimeSpanOutputFormat::WithMeasures, false) == "3 d 10 h 53 min 2 s 500 ms");
+    CPPUNIT_ASSERT_EQUAL("3 d 10 h 53 min 2 s 500 ms"s, test1.toString(TimeSpanOutputFormat::WithMeasures, false));
 
     // test whether ConversionException() is thrown when invalid values are specified
     CPPUNIT_ASSERT_THROW(TimeSpan::fromString("2:34a:53:32.5"), ConversionException);
diff --git a/tests/conversiontests.cpp b/tests/conversiontests.cpp
index b10ace2..2bc1849 100644
--- a/tests/conversiontests.cpp
+++ b/tests/conversiontests.cpp
@@ -263,19 +263,19 @@ void ConversionTests::testStringConversions()
     CPPUNIT_ASSERT(interpretIntegerAsString<uint32>(0x54455354) == "TEST");
 
     // splitString() / joinStrings()
-    auto splitJoinTest = joinStrings(splitString<vector<string> >(",a,,ab,ABC,s", ",", EmptyPartsTreat::Keep), " ", false, "(", ")");
-    CPPUNIT_ASSERT(splitJoinTest == "() (a) () (ab) (ABC) (s)");
-    splitJoinTest = joinStrings(splitString<vector<string> >(",a,,ab,ABC,s", ",", EmptyPartsTreat::Keep), " ", true, "(", ")");
-    CPPUNIT_ASSERT(splitJoinTest == "(a) (ab) (ABC) (s)");
-    splitJoinTest = joinStrings(splitString<vector<string> >(",a,,ab,ABC,s", ",", EmptyPartsTreat::Omit), " ", false, "(", ")");
-    CPPUNIT_ASSERT(splitJoinTest == "(a) (ab) (ABC) (s)");
-    splitJoinTest = joinStrings(splitString<vector<string> >(",a,,ab,ABC,s", ",", EmptyPartsTreat::Merge), " ", false, "(", ")");
-    CPPUNIT_ASSERT(splitJoinTest == "(a,ab) (ABC) (s)");
+    string splitJoinTest = joinStrings(splitString<vector<string> >(",a,,ab,ABC,s"s, ","s, EmptyPartsTreat::Keep), " "s, false, "("s, ")"s);
+    CPPUNIT_ASSERT_EQUAL("() (a) () (ab) (ABC) (s)"s, splitJoinTest);
+    splitJoinTest = joinStrings(splitString<vector<string> >(",a,,ab,ABC,s"s, ","s, EmptyPartsTreat::Keep), " "s, true, "("s, ")"s);
+    CPPUNIT_ASSERT_EQUAL("(a) (ab) (ABC) (s)"s, splitJoinTest);
+    splitJoinTest = joinStrings(splitString<vector<string> >(",a,,ab,ABC,s"s, ","s, EmptyPartsTreat::Omit), " "s, false, "("s, ")"s);
+    CPPUNIT_ASSERT_EQUAL("(a) (ab) (ABC) (s)"s, splitJoinTest);
+    splitJoinTest = joinStrings(splitString<vector<string> >(",a,,ab,ABC,s"s, ","s, EmptyPartsTreat::Merge), " "s, false, "("s, ")"s);
+    CPPUNIT_ASSERT_EQUAL("(a,ab) (ABC) (s)"s, splitJoinTest);
 
     // findAndReplace()
     string findReplaceTest("findAndReplace()");
     findAndReplace<string>(findReplaceTest, "And", "Or");
-    CPPUNIT_ASSERT(findReplaceTest == "findOrReplace()");
+    CPPUNIT_ASSERT_EQUAL("findOrReplace()"s, findReplaceTest);
 
     // startsWith()
     CPPUNIT_ASSERT(!startsWith<string>(findReplaceTest, "findAnd"));
@@ -312,8 +312,8 @@ void ConversionTests::testStringBuilder()
     CPPUNIT_ASSERT_EQUAL(string("foobarfoo2bar2"), tupleToString(string("foo") % "bar" % string("foo2") % "bar2"));
 
     // construction of string-tuple and final conversion to string works
-    CPPUNIT_ASSERT_EQUAL_MESSAGE("result can be passed to any function taking a std::string", string("123456789"), functionTakingString("12" % string("34") % '5' % 67 + "89"));
+    CPPUNIT_ASSERT_EQUAL_MESSAGE("result can be passed to any function taking a std::string"s, "123456789"s, functionTakingString("12" % string("34") % '5' % 67 + "89"));
     constexpr double velocityExample = 27.0;
-    CPPUNIT_ASSERT_EQUAL_MESSAGE("real-word example", string("velocity: 27 km/h (7.5 m/s)"), functionTakingString("velocity: " % numberToString(velocityExample) % " km/h (" % numberToString(velocityExample / 3.6) + " m/s)"));
-    CPPUNIT_ASSERT_EQUAL_MESSAGE("regular + operator still works (no problems with ambiguity)", string("regular + still works"), string("regular") + " + still works");
+    CPPUNIT_ASSERT_EQUAL_MESSAGE("real-word example"s, "velocity: 27 km/h (7.5 m/s)"s, functionTakingString("velocity: " % numberToString(velocityExample) % " km/h (" % numberToString(velocityExample / 3.6) + " m/s)"));
+    CPPUNIT_ASSERT_EQUAL_MESSAGE("regular + operator still works (no problems with ambiguity)"s, "regular + still works"s, "regular"s + " + still works");
 }
diff --git a/tests/iotests.cpp b/tests/iotests.cpp
index d523239..0d9b990 100644
--- a/tests/iotests.cpp
+++ b/tests/iotests.cpp
@@ -229,8 +229,8 @@ void IoTests::testBitReader()
  */
 void IoTests::testPathUtilities()
 {
-    CPPUNIT_ASSERT(fileName("/usr/lib/libc++utilities.so") == "libc++utilities.so");
-    CPPUNIT_ASSERT(directory("/usr/lib/libc++utilities.so") == "/usr/lib/");
+    CPPUNIT_ASSERT_EQUAL("libc++utilities.so"s, fileName("/usr/lib/libc++utilities.so"));
+    CPPUNIT_ASSERT_EQUAL("/usr/lib/"s, directory("/usr/lib/libc++utilities.so"));
     CPPUNIT_ASSERT(directory("libc++utilities.so").empty());
     string invalidPath("lib/c++uti*lities.so?");
     removeInvalidChars(invalidPath);