tst_compilation: Add a test for compilation of a large number of types

As I'll be touching QQmlImport, it would be good to ensure it doesn't
regress. This may also be useful for future such changes (e.g. I want to
try play around with how the implicit import is handled).

Results for me on a recent dev snapshot, 2013 rmbp:

********* Start testing of tst_compilation *********
Config: Using QtTest library 5.9.0, Qt 5.9.0 (x86_64-little_endian-lp64 shared (dynamic) release build; by Clang 8.0.0 (clang-800.0.42.1) (Apple))
PASS   : tst_compilation::initTestCase()
PASS   : tst_compilation::bigimport(10, qmldir)
RESULT : tst_compilation::bigimport():"10, qmldir":
     3.6 msecs per iteration (total: 59, iterations: 16)
PASS   : tst_compilation::bigimport(100, qmldir)
RESULT : tst_compilation::bigimport():"100, qmldir":
     54 msecs per iteration (total: 54, iterations: 1)
PASS   : tst_compilation::bigimport(1000, qmldir)
RESULT : tst_compilation::bigimport():"1000, qmldir":
     558 msecs per iteration (total: 558, iterations: 1)
PASS   : tst_compilation::bigimport(10, noqmldir)
RESULT : tst_compilation::bigimport():"10, noqmldir":
     5.0 msecs per iteration (total: 80, iterations: 16)
PASS   : tst_compilation::bigimport(100, noqmldir)
RESULT : tst_compilation::bigimport():"100, noqmldir":
     58 msecs per iteration (total: 58, iterations: 1)
PASS   : tst_compilation::bigimport(1000, noqmldir)
RESULT : tst_compilation::bigimport():"1000, noqmldir":
     558 msecs per iteration (total: 558, iterations: 1)
PASS   : tst_compilation::cleanupTestCase()
Totals: 8 passed, 0 failed, 0 skipped, 0 blacklisted, 22400ms
********* Finished testing of tst_compilation *********

Change-Id: I7159e561fb13a3c48e966d5b963dc0ef1ca783e3
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

tests/benchmarks/qml/compilation/tst_compilation.cpp

@@ -51,6 +51,9 @@ private slots:
     void jsparser_data();
     void jsparser();
 
+    void bigimport_data();
+    void bigimport();
+
 private:
     QQmlEngine engine;
 };
@@ -115,6 +118,74 @@ void tst_compilation::jsparser()
     }
 }
 
+void tst_compilation::bigimport_data()
+{
+    QTest::addColumn<int>("filesToCreate");
+    QTest::addColumn<bool>("writeQmldir");
+
+    QTest::newRow("10, qmldir")
+        << 10 << true;
+    QTest::newRow("100, qmldir")
+        << 100 << true;
+    QTest::newRow("1000, qmldir")
+        << 1000 << true;
+
+    QTest::newRow("10, noqmldir")
+        << 10 << false;
+    QTest::newRow("100, noqmldir")
+        << 100 << false;
+    QTest::newRow("1000, noqmldir")
+        << 1000 << false;
+}
+
+void tst_compilation::bigimport()
+{
+    QFETCH(int, filesToCreate);
+    QFETCH(bool, writeQmldir);
+    QTemporaryDir d;
+    //d.setAutoRemove(false); // for debugging
+
+    QString p;
+    {
+        for (int i = 0; i < filesToCreate; ++i) {
+            QFile f(d.path() + QDir::separator() + QString::fromLatin1("Type%1.qml").arg(i));
+            QVERIFY(f.open(QIODevice::WriteOnly));
+            f.write("import QtQuick 2.0\n");
+            f.write("import \".\"\n");
+            f.write("Item {}\n");
+        }
+
+        QFile qmldir(d.path() + QDir::separator() + "qmldir");
+        if (writeQmldir)
+            QVERIFY(qmldir.open(QIODevice::WriteOnly));
+        QFile main(d.path() + QDir::separator() + "main.qml");
+        QVERIFY(main.open(QIODevice::WriteOnly));
+        p = QFileInfo(main).absoluteFilePath();
+        //qDebug() << p; // for debugging
+
+        main.write("import QtQuick 2.0\n");
+        main.write("import \".\"\n");
+        main.write("\n");
+        main.write("Item {\n");
+
+        for (int i = 0; i < filesToCreate; ++i) {
+            main.write(qPrintable(QString::fromLatin1("Type%1 {}\n").arg(i)));
+            if (writeQmldir)
+                qmldir.write(qPrintable(QString::fromLatin1("Type%1 1.0 Type%1.qml\n").arg(i)));
+        }
+
+        main.write("}");
+    }
+
+    QBENCHMARK {
+        QQmlEngine e;
+        QQmlComponent c(&e, p);
+        QCOMPARE(c.status(), QQmlComponent::Ready);
+        QScopedPointer<QObject> o(c.create());
+        QVERIFY(o->children().count() == filesToCreate);
+    }
+}
+
 QTEST_MAIN(tst_compilation)
 
 #include "tst_compilation.moc"