diff --git a/autotests/importexportvcardtest.cpp b/autotests/importexportvcardtest.cpp
--- a/autotests/importexportvcardtest.cpp
+++ b/autotests/importexportvcardtest.cpp
@@ -41,8 +41,8 @@
     const QList<QByteArray> outputLines = outputData.split('\n');
     const QList<QByteArray> outputRefLines = expected.split('\n');
     for (int i = 0; i < qMin(outputLines.count(), outputRefLines.count()); ++i) {
-        const QByteArray actual = outputLines.at(i);
-        const QByteArray expect = outputRefLines.at(i);
+        const QByteArray &actual = outputLines.at(i);
+        const QByteArray &expect = outputRefLines.at(i);
         if (actual != expect) {
             qCritical() << "Mismatch at output line" << (i + 1);
             QCOMPARE(actual, expect);
diff --git a/autotests/phonenumbertest.cpp b/autotests/phonenumbertest.cpp
--- a/autotests/phonenumbertest.cpp
+++ b/autotests/phonenumbertest.cpp
@@ -198,7 +198,7 @@
     KContacts::VCardTool vcard;
     const KContacts::AddresseeList lst = vcard.parseVCards(vcarddata);
     QCOMPARE(lst.count(), 1);
-    KContacts::Addressee addr = lst.at(0);
+    const KContacts::Addressee &addr = lst.at(0);
     QCOMPARE(addr.phoneNumbers().count(), 1);
     KContacts::PhoneNumber number1 = addr.phoneNumbers().at(0);
     QCOMPARE(number1.number(), QLatin1String("+1-919-676-9564"));
@@ -304,7 +304,7 @@
     KContacts::VCardTool vcard;
     const KContacts::AddresseeList lst = vcard.parseVCards(vcarddata);
     QCOMPARE(lst.count(), 1);
-    KContacts::Addressee addr = lst.at(0);
+    const KContacts::Addressee &addr = lst.at(0);
     QCOMPARE(addr.phoneNumbers().count(), 3);
 }
 
@@ -325,7 +325,7 @@
     KContacts::VCardTool vcard;
     const KContacts::AddresseeList lst = vcard.parseVCards(vcarddata);
     QCOMPARE(lst.count(), 1);
-    KContacts::Addressee addr = lst.at(0);
+    const KContacts::Addressee &addr = lst.at(0);
     QCOMPARE(addr.phoneNumbers().count(), 3);
 }
 
diff --git a/autotests/testroundtrip.cpp b/autotests/testroundtrip.cpp
--- a/autotests/testroundtrip.cpp
+++ b/autotests/testroundtrip.cpp
@@ -107,8 +107,8 @@
     const QList<QByteArray> outputLines = outputData.split('\n');
     const QList<QByteArray> outputRefLines = outputRefData.split('\n');
     for (int i = 0; i < qMin(outputLines.count(), outputRefLines.count()); ++i) {
-        const QByteArray actual = outputLines.at(i);
-        const QByteArray expect = outputRefLines.at(i);
+        const QByteArray &actual = outputLines.at(i);
+        const QByteArray &expect = outputRefLines.at(i);
         if (actual != expect) {
             qCritical() << "Mismatch in" << version << "output line" << (i + 1);
             QCOMPARE(actual, expect);
diff --git a/src/converter/ldifconverter.cpp b/src/converter/ldifconverter.cpp
--- a/src/converter/ldifconverter.cpp
+++ b/src/converter/ldifconverter.cpp
@@ -100,7 +100,7 @@
     t << "objectclass: groupOfNames\n";
 
     for (int i = 0; i < contactGroup.dataCount(); ++i) {
-        ContactGroup::Data data = contactGroup.data(i);
+        const ContactGroup::Data &data = contactGroup.data(i);
         const QString value = QStringLiteral("cn=%1,mail=%2").arg(data.name(), data.email());
         ldif_out(t, QStringLiteral("member"), value);
     }
diff --git a/src/generator/main.cpp b/src/generator/main.cpp
--- a/src/generator/main.cpp
+++ b/src/generator/main.cpp
@@ -139,8 +139,9 @@
     // we must sort exactly as we do this for lookup
     std::sort(processedList.begin(), processedList.end(), [](const Elem &lhs, const Elem &rhs) {
         const auto c = strcmp(lhs.name.constData(), rhs.name.constData());
-        if (c == 0)
+        if (c == 0) {
             return lhs.isoCode < rhs.isoCode;
+        }
         return  c < 0;
     });
 
diff --git a/src/picture.cpp b/src/picture.cpp
--- a/src/picture.cpp
+++ b/src/picture.cpp
@@ -136,8 +136,8 @@
 bool Picture::isEmpty() const
 {
     return
-        (d->mIntern == false && d->mUrl.isEmpty())
-        || (d->mIntern == true && d->mData.isNull() && d->mRawData.isEmpty());
+        (!d->mIntern && d->mUrl.isEmpty()) ||
+        (d->mIntern && d->mData.isNull() && d->mRawData.isEmpty());
 }
 
 void Picture::setUrl(const QString &url)
diff --git a/tests/testread.cpp b/tests/testread.cpp
--- a/tests/testread.cpp
+++ b/tests/testread.cpp
@@ -19,7 +19,6 @@
 */
 
 #include <iostream>
-#include <stdlib.h>
 
 #include <QFile>