diff --git a/tests/auto/corelib/text/qstring/tst_qstring.cpp b/tests/auto/corelib/text/qstring/tst_qstring.cpp
index 0a24a864eb2..0f1c5083353 100644
--- a/tests/auto/corelib/text/qstring/tst_qstring.cpp
+++ b/tests/auto/corelib/text/qstring/tst_qstring.cpp
@@ -3461,6 +3461,11 @@ void tst_QString::assign()
         QCOMPARE(str.assign(tstr.begin(), tstr.end()), u"(ノಠ益ಠ)\0ノ彡┻━┻");
         QCOMPARE(str.size(), 6);
 
+        auto oldCap = str.capacity();
+        str.assign(tstr.begin(), tstr.begin()); // empty range
+        QCOMPARE_EQ(str.capacity(), oldCap);
+        QCOMPARE_EQ(str.size(), 0);
+
         const char16_t c16[] = u"٩(⁎❛ᴗ❛⁎)۶ 🤷";
         str.assign(std::begin(c16), std::end(c16) - 1);
         QCOMPARE(str, c16);
@@ -3469,6 +3474,11 @@ void tst_QString::assign()
         str.assign(c16str.begin(), c16str.end());
         QCOMPARE(str, c16);
 
+        oldCap = str.capacity();
+        str.assign(c16str.begin(), c16str.begin()); // empty range
+        QCOMPARE_EQ(str.capacity(), oldCap);
+        QCOMPARE_EQ(str.size(), 0);
+
         const char32_t c32[] = U"٩(⁎❛ᴗ❛⁎)۶ 🤷";
         str.assign(std::begin(c32), std::end(c32) - 1);
         QCOMPARE(str, c16);
@@ -3477,6 +3487,11 @@ void tst_QString::assign()
         str.assign(c32str.begin(), c32str.end());
         QCOMPARE(str, c16);
 
+        oldCap = str.capacity();
+        str.assign(c32str.begin(), c32str.begin()); // empty range
+        QCOMPARE_EQ(str.capacity(), oldCap);
+        QCOMPARE_EQ(str.size(), 0);
+
         QVarLengthArray<QLatin1Char, 5> l1ch = {'F'_L1, 'G'_L1, 'H'_L1, 'I'_L1, 'J'_L1};
         str.assign(l1ch.begin(), l1ch.end());
         QCOMPARE(str, u"FGHIJ");
@@ -3495,6 +3510,11 @@ void tst_QString::assign()
         std::stringstream ss("50 51 52 53 54");
         str.assign(std::istream_iterator<ushort>{ss}, std::istream_iterator<ushort>{});
         QCOMPARE(str, u"23456");
+
+        oldCap = str.capacity();
+        str.assign(std::istream_iterator<ushort>{}, std::istream_iterator<ushort>{}); // empty range
+        QCOMPARE_EQ(str.capacity(), oldCap);
+        QCOMPARE_EQ(str.size(), 0);
     }
     // Test chaining
     {