diff --git a/src/testlib/qtest.h b/src/testlib/qtest.h
index 4bf5e018a7..cee01e7217 100644
--- a/src/testlib/qtest.h
+++ b/src/testlib/qtest.h
@@ -380,7 +380,7 @@ inline char *toString(const std::pair<T1, T2> &pair)
 {
     const QScopedArrayPointer<char> first(toString(pair.first));
     const QScopedArrayPointer<char> second(toString(pair.second));
-    return toString(QString::asprintf("std::pair(%s,%s)", first.data(), second.data()));
+    return formatString("std::pair(", ")", 2, first.data(), second.data());
 }
 
 template <typename Tuple, int... I>
diff --git a/tests/auto/testlib/selftests/expected_pairdiagnostics.junitxml b/tests/auto/testlib/selftests/expected_pairdiagnostics.junitxml
index 4086bd8273..1f6ce0ba06 100644
--- a/tests/auto/testlib/selftests/expected_pairdiagnostics.junitxml
+++ b/tests/auto/testlib/selftests/expected_pairdiagnostics.junitxml
@@ -8,13 +8,13 @@
   <testcase name="initTestCase" result="pass" time="@TEST_DURATION@"/>
   <testcase name="testQPair" result="fail" time="@TEST_DURATION@">
     <failure result="fail" message="Compared values are not the same
-   Actual   (pair1): &quot;std::pair(1,1)&quot;
-   Expected (pair2): &quot;std::pair(1,2)&quot;"/>
+   Actual   (pair1): std::pair(1, 1)
+   Expected (pair2): std::pair(1, 2)"/>
   </testcase>
   <testcase name="testStdPair" result="fail" time="@TEST_DURATION@">
     <failure result="fail" message="Compared values are not the same
-   Actual   (pair1): &quot;std::pair(1,1)&quot;
-   Expected (pair2): &quot;std::pair(1,2)&quot;"/>
+   Actual   (pair1): std::pair(1, 1)
+   Expected (pair2): std::pair(1, 2)"/>
   </testcase>
   <testcase name="cleanupTestCase" result="pass" time="@TEST_DURATION@"/>
   <system-err/>
diff --git a/tests/auto/testlib/selftests/expected_pairdiagnostics.lightxml b/tests/auto/testlib/selftests/expected_pairdiagnostics.lightxml
index e4ceacc9e3..2770b4394a 100644
--- a/tests/auto/testlib/selftests/expected_pairdiagnostics.lightxml
+++ b/tests/auto/testlib/selftests/expected_pairdiagnostics.lightxml
@@ -10,16 +10,16 @@
 <TestFunction name="testQPair">
 <Incident type="fail" file="qtbase/tests/auto/testlib/selftests/pairdiagnostics/tst_pairdiagnostics.cpp" line="0">
     <Description><![CDATA[Compared values are not the same
-   Actual   (pair1): "std::pair(1,1)"
-   Expected (pair2): "std::pair(1,2)"]]></Description>
+   Actual   (pair1): std::pair(1, 1)
+   Expected (pair2): std::pair(1, 2)]]></Description>
 </Incident>
     <Duration msecs="0"/>
 </TestFunction>
 <TestFunction name="testStdPair">
 <Incident type="fail" file="qtbase/tests/auto/testlib/selftests/pairdiagnostics/tst_pairdiagnostics.cpp" line="0">
     <Description><![CDATA[Compared values are not the same
-   Actual   (pair1): "std::pair(1,1)"
-   Expected (pair2): "std::pair(1,2)"]]></Description>
+   Actual   (pair1): std::pair(1, 1)
+   Expected (pair2): std::pair(1, 2)]]></Description>
 </Incident>
     <Duration msecs="0"/>
 </TestFunction>
diff --git a/tests/auto/testlib/selftests/expected_pairdiagnostics.tap b/tests/auto/testlib/selftests/expected_pairdiagnostics.tap
index 25718d0d4c..a5ffbc31ef 100644
--- a/tests/auto/testlib/selftests/expected_pairdiagnostics.tap
+++ b/tests/auto/testlib/selftests/expected_pairdiagnostics.tap
@@ -5,10 +5,10 @@ not ok 2 - testQPair()
   ---
   type: QCOMPARE
   message: Compared values are not the same
-  wanted: "std::pair(1,2)" (pair2)
-  found: "std::pair(1,1)" (pair1)
-  expected: "std::pair(1,2)" (pair2)
-  actual: "std::pair(1,1)" (pair1)
+  wanted: std::pair(1, 2) (pair2)
+  found: std::pair(1, 1) (pair1)
+  expected: std::pair(1, 2) (pair2)
+  actual: std::pair(1, 1) (pair1)
   at: tst_PairDiagnostics::testQPair() (qtbase/tests/auto/testlib/selftests/pairdiagnostics/tst_pairdiagnostics.cpp:0)
   file: qtbase/tests/auto/testlib/selftests/pairdiagnostics/tst_pairdiagnostics.cpp
   line: 0
@@ -17,10 +17,10 @@ not ok 3 - testStdPair()
   ---
   type: QCOMPARE
   message: Compared values are not the same
-  wanted: "std::pair(1,2)" (pair2)
-  found: "std::pair(1,1)" (pair1)
-  expected: "std::pair(1,2)" (pair2)
-  actual: "std::pair(1,1)" (pair1)
+  wanted: std::pair(1, 2) (pair2)
+  found: std::pair(1, 1) (pair1)
+  expected: std::pair(1, 2) (pair2)
+  actual: std::pair(1, 1) (pair1)
   at: tst_PairDiagnostics::testStdPair() (qtbase/tests/auto/testlib/selftests/pairdiagnostics/tst_pairdiagnostics.cpp:0)
   file: qtbase/tests/auto/testlib/selftests/pairdiagnostics/tst_pairdiagnostics.cpp
   line: 0
diff --git a/tests/auto/testlib/selftests/expected_pairdiagnostics.teamcity b/tests/auto/testlib/selftests/expected_pairdiagnostics.teamcity
index a86f4fa254..01f4a232e2 100644
--- a/tests/auto/testlib/selftests/expected_pairdiagnostics.teamcity
+++ b/tests/auto/testlib/selftests/expected_pairdiagnostics.teamcity
@@ -2,10 +2,10 @@
 ##teamcity[testStarted name='initTestCase()' flowId='tst_PairDiagnostics']
 ##teamcity[testFinished name='initTestCase()' flowId='tst_PairDiagnostics']
 ##teamcity[testStarted name='testQPair()' flowId='tst_PairDiagnostics']
-##teamcity[testFailed name='testQPair()' message='Failure! |[Loc: qtbase/tests/auto/testlib/selftests/pairdiagnostics/tst_pairdiagnostics.cpp(0)|]' details='Compared values are not the same|n Actual (pair1): "std::pair(1,1)"|n Expected (pair2): "std::pair(1,2)"' flowId='tst_PairDiagnostics']
+##teamcity[testFailed name='testQPair()' message='Failure! |[Loc: qtbase/tests/auto/testlib/selftests/pairdiagnostics/tst_pairdiagnostics.cpp(0)|]' details='Compared values are not the same|n Actual (pair1): std::pair(1, 1)|n Expected (pair2): std::pair(1, 2)' flowId='tst_PairDiagnostics']
 ##teamcity[testFinished name='testQPair()' flowId='tst_PairDiagnostics']
 ##teamcity[testStarted name='testStdPair()' flowId='tst_PairDiagnostics']
-##teamcity[testFailed name='testStdPair()' message='Failure! |[Loc: qtbase/tests/auto/testlib/selftests/pairdiagnostics/tst_pairdiagnostics.cpp(0)|]' details='Compared values are not the same|n Actual (pair1): "std::pair(1,1)"|n Expected (pair2): "std::pair(1,2)"' flowId='tst_PairDiagnostics']
+##teamcity[testFailed name='testStdPair()' message='Failure! |[Loc: qtbase/tests/auto/testlib/selftests/pairdiagnostics/tst_pairdiagnostics.cpp(0)|]' details='Compared values are not the same|n Actual (pair1): std::pair(1, 1)|n Expected (pair2): std::pair(1, 2)' flowId='tst_PairDiagnostics']
 ##teamcity[testFinished name='testStdPair()' flowId='tst_PairDiagnostics']
 ##teamcity[testStarted name='cleanupTestCase()' flowId='tst_PairDiagnostics']
 ##teamcity[testFinished name='cleanupTestCase()' flowId='tst_PairDiagnostics']
diff --git a/tests/auto/testlib/selftests/expected_pairdiagnostics.txt b/tests/auto/testlib/selftests/expected_pairdiagnostics.txt
index cbb8b764ff..b225b4c55f 100644
--- a/tests/auto/testlib/selftests/expected_pairdiagnostics.txt
+++ b/tests/auto/testlib/selftests/expected_pairdiagnostics.txt
@@ -2,12 +2,12 @@
 Config: Using QtTest library
 PASS   : tst_PairDiagnostics::initTestCase()
 FAIL!  : tst_PairDiagnostics::testQPair() Compared values are not the same
-   Actual   (pair1): "std::pair(1,1)"
-   Expected (pair2): "std::pair(1,2)"
+   Actual   (pair1): std::pair(1, 1)
+   Expected (pair2): std::pair(1, 2)
    Loc: [qtbase/tests/auto/testlib/selftests/pairdiagnostics/tst_pairdiagnostics.cpp(0)]
 FAIL!  : tst_PairDiagnostics::testStdPair() Compared values are not the same
-   Actual   (pair1): "std::pair(1,1)"
-   Expected (pair2): "std::pair(1,2)"
+   Actual   (pair1): std::pair(1, 1)
+   Expected (pair2): std::pair(1, 2)
    Loc: [qtbase/tests/auto/testlib/selftests/pairdiagnostics/tst_pairdiagnostics.cpp(0)]
 PASS   : tst_PairDiagnostics::cleanupTestCase()
 Totals: 2 passed, 2 failed, 0 skipped, 0 blacklisted, 0ms
diff --git a/tests/auto/testlib/selftests/expected_pairdiagnostics.xml b/tests/auto/testlib/selftests/expected_pairdiagnostics.xml
index 89e8ca49a6..503ea937aa 100644
--- a/tests/auto/testlib/selftests/expected_pairdiagnostics.xml
+++ b/tests/auto/testlib/selftests/expected_pairdiagnostics.xml
@@ -12,16 +12,16 @@
 <TestFunction name="testQPair">
 <Incident type="fail" file="qtbase/tests/auto/testlib/selftests/pairdiagnostics/tst_pairdiagnostics.cpp" line="0">
     <Description><![CDATA[Compared values are not the same
-   Actual   (pair1): "std::pair(1,1)"
-   Expected (pair2): "std::pair(1,2)"]]></Description>
+   Actual   (pair1): std::pair(1, 1)
+   Expected (pair2): std::pair(1, 2)]]></Description>
 </Incident>
     <Duration msecs="0"/>
 </TestFunction>
 <TestFunction name="testStdPair">
 <Incident type="fail" file="qtbase/tests/auto/testlib/selftests/pairdiagnostics/tst_pairdiagnostics.cpp" line="0">
     <Description><![CDATA[Compared values are not the same
-   Actual   (pair1): "std::pair(1,1)"
-   Expected (pair2): "std::pair(1,2)"]]></Description>
+   Actual   (pair1): std::pair(1, 1)
+   Expected (pair2): std::pair(1, 2)]]></Description>
 </Incident>
     <Duration msecs="0"/>
 </TestFunction>