diff --git a/tests/strings/strings.cpp b/tests/strings/strings.cpp
index 3562510b51..1cf282b0eb 100644
--- a/tests/strings/strings.cpp
+++ b/tests/strings/strings.cpp
@@ -63,6 +63,7 @@ private:
         CPPUNIT_TEST( IndexedAccess );
         CPPUNIT_TEST( BeforeAndAfter );
         CPPUNIT_TEST( ScopedBuffers );
+        CPPUNIT_TEST( SupplementaryUniChar );
     CPPUNIT_TEST_SUITE_END();
 
     void String();
@@ -98,6 +99,7 @@ private:
     void IndexedAccess();
     void BeforeAndAfter();
     void ScopedBuffers();
+    void SupplementaryUniChar();
 
     wxDECLARE_NO_COPY_CLASS(StringTestCase);
 };
@@ -1142,3 +1144,171 @@ void StringTestCase::ScopedBuffers()
     buf5.extend(len);
     CPPUNIT_ASSERT_EQUAL('\0', buf5.data()[len]);
 }
+
+void StringTestCase::SupplementaryUniChar()
+{
+#if wxUSE_UNICODE
+    // Test wxString(wxUniChar ch, size_t nRepeat = 1),
+    // which is implemented upon assign(size_t n, wxUniChar ch).
+    {
+        wxString s(wxUniChar(0x12345));
+#if wxUSE_UNICODE_UTF16
+        CPPUNIT_ASSERT_EQUAL(2, s.length());
+        CPPUNIT_ASSERT_EQUAL(0xD808, s[0].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0xDF45, s[1].GetValue());
+#else
+        CPPUNIT_ASSERT_EQUAL(1, s.length());
+        CPPUNIT_ASSERT_EQUAL(0x12345, s[0].GetValue());
+#endif
+    }
+
+    // Test operator=(wxUniChar ch).
+    {
+        wxString s;
+        s = wxUniChar(0x23456);
+#if wxUSE_UNICODE_UTF16
+        CPPUNIT_ASSERT_EQUAL(2, s.length());
+        CPPUNIT_ASSERT_EQUAL(0xD84D, s[0].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0xDC56, s[1].GetValue());
+#else
+        CPPUNIT_ASSERT_EQUAL(1, s.length());
+        CPPUNIT_ASSERT_EQUAL(0x23456, s[0].GetValue());
+#endif
+    }
+
+    // Test operator+=(wxUniChar ch).
+    {
+        wxString s = "A";
+        s += wxUniChar(0x34567);
+#if wxUSE_UNICODE_UTF16
+        CPPUNIT_ASSERT_EQUAL(3, s.length());
+        CPPUNIT_ASSERT_EQUAL(0xD891, s[1].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0xDD67, s[2].GetValue());
+#else
+        CPPUNIT_ASSERT_EQUAL(2, s.length());
+        CPPUNIT_ASSERT_EQUAL(0x34567, s[1].GetValue());
+#endif
+    }
+
+    // Test operator<<(wxUniChar ch),
+    // which is implemented upon append(size_t n, wxUniChar ch).
+    {
+        wxString s = "A";
+        s << wxUniChar(0x45678);
+#if wxUSE_UNICODE_UTF16
+        CPPUNIT_ASSERT_EQUAL(3, s.length());
+        CPPUNIT_ASSERT_EQUAL(0xD8D5, s[1].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0xDE78, s[2].GetValue());
+#else
+        CPPUNIT_ASSERT_EQUAL(2, s.length());
+        CPPUNIT_ASSERT_EQUAL(0x45678, s[1].GetValue());
+#endif
+    }
+
+    // Test insert(size_t nPos, size_t n, wxUniChar ch).
+    {
+        wxString s = L"\x3042\x208\x3059";
+        s.insert(1, 2, wxUniChar(0x12345));
+#if wxUSE_UNICODE_UTF16
+        CPPUNIT_ASSERT_EQUAL(7, s.length());
+        CPPUNIT_ASSERT_EQUAL(0xD808, s[1].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0xDF45, s[2].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0xD808, s[3].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0xDF45, s[4].GetValue());
+#else
+        CPPUNIT_ASSERT_EQUAL(5, s.length());
+        CPPUNIT_ASSERT_EQUAL(0x12345, s[1].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0x12345, s[2].GetValue());
+#endif
+    }
+
+    // Test insert(iterator it, wxUniChar ch).
+    {
+        wxString s = L"\x3042\x208\x3059";
+        s.insert(s.begin() + 1, wxUniChar(0x23456));
+#if wxUSE_UNICODE_UTF16
+        CPPUNIT_ASSERT_EQUAL(5, s.length());
+        CPPUNIT_ASSERT_EQUAL(0xD84D, s[1].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0xDC56, s[2].GetValue());
+#else
+        CPPUNIT_ASSERT_EQUAL(4, s.length());
+        CPPUNIT_ASSERT_EQUAL(0x23456, s[1].GetValue());
+#endif
+    }
+
+    // Test insert(iterator it, size_type n, wxUniChar ch).
+    {
+        wxString s = L"\x3042\x208\x3059";
+        s.insert(s.begin() + 1, 2, wxUniChar(0x34567));
+#if wxUSE_UNICODE_UTF16
+        CPPUNIT_ASSERT_EQUAL(7, s.length());
+        CPPUNIT_ASSERT_EQUAL(0xD891, s[1].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0xDD67, s[2].GetValue());
+#else
+        CPPUNIT_ASSERT_EQUAL(5, s.length());
+        CPPUNIT_ASSERT_EQUAL(0x34567, s[1].GetValue());
+#endif
+    }
+
+    // Test replace(size_t nStart, size_t nLen, size_t nCount, wxUniChar ch).
+    {
+        wxString s = L"\x3042\x208\x3059";
+        s.replace(1, 2, 2, wxUniChar(0x45678));
+#if wxUSE_UNICODE_UTF16
+        CPPUNIT_ASSERT_EQUAL(5, s.length());
+        CPPUNIT_ASSERT_EQUAL(0xD8D5, s[1].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0xDE78, s[2].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0xD8D5, s[3].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0xDE78, s[4].GetValue());
+#else
+        CPPUNIT_ASSERT_EQUAL(3, s.length());
+        CPPUNIT_ASSERT_EQUAL(0x45678, s[1].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0x45678, s[2].GetValue());
+#endif
+    }
+
+    // Test replace(iterator first, iterator last, size_type n, wxUniChar ch).
+    {
+        wxString s = L"\x3042\x208\x3059";
+        s.replace(s.begin() + 1, s.end(), 2, wxUniChar(0x34567));
+#if wxUSE_UNICODE_UTF16
+        CPPUNIT_ASSERT_EQUAL(5, s.length());
+        CPPUNIT_ASSERT_EQUAL(0xD891, s[1].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0xDD67, s[2].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0xD891, s[3].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0xDD67, s[4].GetValue());
+#else
+        CPPUNIT_ASSERT_EQUAL(3, s.length());
+        CPPUNIT_ASSERT_EQUAL(0x34567, s[1].GetValue());
+        CPPUNIT_ASSERT_EQUAL(0x34567, s[2].GetValue());
+#endif
+    }
+
+    // Test find(wxUniChar ch, size_t nStart = 0)
+    // and rfind(wxUniChar ch, size_t nStart = npos).
+    {
+        wxString s = L"\x308\x2063";
+        s << wxUniChar(0x12345);
+        s << "x";
+        s += wxUniChar(0x12345);
+        s += "y";
+#if wxUSE_UNICODE_UTF16
+        CPPUNIT_ASSERT_EQUAL(8, s.length());
+        CPPUNIT_ASSERT_EQUAL(2, s.find(wxUniChar(0x12345)));
+        CPPUNIT_ASSERT_EQUAL(5, s.find(wxUniChar(0x12345), 3));
+        CPPUNIT_ASSERT_EQUAL(5, s.rfind(wxUniChar(0x12345)));
+        CPPUNIT_ASSERT_EQUAL(2, s.rfind(wxUniChar(0x12345), 4));
+#else
+        CPPUNIT_ASSERT_EQUAL(6, s.length());
+        CPPUNIT_ASSERT_EQUAL(2, s.find(wxUniChar(0x12345)));
+        CPPUNIT_ASSERT_EQUAL(4, s.find(wxUniChar(0x12345), 3));
+        CPPUNIT_ASSERT_EQUAL(4, s.rfind(wxUniChar(0x12345)));
+        CPPUNIT_ASSERT_EQUAL(2, s.rfind(wxUniChar(0x12345), 3));
+#endif
+    }
+
+    /* Not tested here:
+         find_first_of, find_last_of, find_first_not_of, find_last_not_of
+    */
+#endif
+}