testlib: add QFINDTESTDATA macro for finding testdata files

Automated tests often need to load some data from external files.
Currently, a wide variety of approaches for this have been used in Qt
autotests, including:

  - embed the source directory into the test binary at compile time, and
    find the testdata relative to that; this fails when the source tree
    is no longer available (e.g. when the tests are deployed to a device).

  - use a path relative to the current working directory, and trust that
    the caller always sets the current working directory such that the
    testdata can be found; this fails when the caller uses a different
    working directory than expected.

  - use a path relative to QCoreApplication::applicationDirPath();
    this fails when source tree != build tree (since testdata is not
    automatically copied into the build tree).

  - compile the files into the binary using the Qt resource system; this
    should work, but does not allow for testing of code which genuinely
    needs external files.

It seems that there is not a simple method for determining the testdata
path which can be reliably used in all circumstances, so various tests
have reinvented the testdata location method in different ways.
Therefore, this is a good candidate for an addition to the testlib API.

The current implementation of QFINDTESTDATA is able to find testdata
in all three of (build tree, install tree, source tree), in that order.

Change-Id: Ib2fed860723ccf437240da3b00db22dfe1a6b56c
Reviewed-by: Jason McDonald <jason.mcdonald@nokia.com>

3 files changed, 156 insertions, 0 deletions

diff --git a/tests/auto/testlib/selftests/findtestdata/findtestdata.cpp b/tests/auto/testlib/selftests/findtestdata/findtestdata.cpp
new file mode 100644
index 0000000000..473ba19798
--- /dev/null
+++ b/tests/auto/testlib/selftests/findtestdata/findtestdata.cpp
@@ -0,0 +1,144 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+
+#include <QtCore/QtCore>
+#include <QtTest/QtTest>
+
+#define TESTFILE "testfile"
+
+class FindTestData: public QObject
+{
+    Q_OBJECT
+private slots:
+    void initTestCase();
+    void cleanupTestCase();
+
+    void paths();
+
+private:
+    bool touch(QString const&);
+};
+
+void FindTestData::initTestCase()
+{
+    // verify that our qt.conf is working as expected.
+    QString app_path = QCoreApplication::applicationDirPath();
+    QString install_path = app_path + "/tests";
+    QVERIFY(QDir("/").mkpath(install_path));
+    QVERIFY(QDir("/").mkpath(install_path + "/findtestdata"));
+    QCOMPARE(QLibraryInfo::location(QLibraryInfo::TestsPath), install_path);
+
+    // make fake source and build directories
+    QVERIFY(QDir("/").mkpath(app_path + "/fakesrc"));
+    QVERIFY(QDir("/").mkpath(app_path + "/fakebuild"));
+}
+
+void FindTestData::cleanupTestCase()
+{
+    QString app_path = QCoreApplication::applicationDirPath();
+    QFile(app_path + "/tests/findtestdata/" TESTFILE).remove();
+    QFile(app_path + "/tests/" TESTFILE).remove();
+    QFile(app_path + "/fakesrc/" TESTFILE).remove();
+    QDir("/").rmpath(app_path + "/tests/findtestdata");
+    QDir("/").rmpath(app_path + "/fakesrc");
+    QDir("/").rmpath(app_path + "/fakebuild");
+}
+
+// Create an empty file at the specified path (or return false)
+bool FindTestData::touch(QString const& path)
+{
+    QFile file(path);
+    if (!file.open(QIODevice::WriteOnly)) {
+        qWarning("Failed to create %s: %s", qPrintable(path), qPrintable(file.errorString()));
+        return false;
+    }
+    return true;
+}
+
+void FindTestData::paths()
+{
+    // There are three possible locations for the testdata.
+    // In this test, we will put the testdata at all three locations,
+    // then remove it from one location at a time and verify that
+    // QFINDTESTDATA correctly falls back each time.
+
+    // 1. relative to test binary.
+    QString app_path = QCoreApplication::applicationDirPath();
+    QString testfile_path1 = app_path + "/" TESTFILE;
+    QVERIFY(touch(testfile_path1));
+
+    // 2. at the test install path (faked via qt.conf)
+    QString testfile_path2 = app_path + "/tests/findtestdata/" TESTFILE;
+    QVERIFY(touch(testfile_path2));
+
+    // 3. at the source path (which we will fake later on)
+    QString testfile_path3 = app_path + "/fakesrc/" TESTFILE;
+    QVERIFY(touch(testfile_path3));
+
+    // OK, all testdata created.  Verify that they are found in correct priority order.
+
+    QCOMPARE(QFINDTESTDATA(TESTFILE), testfile_path1);
+    QVERIFY(QFile(testfile_path1).remove());
+
+    QCOMPARE(QFINDTESTDATA(TESTFILE), testfile_path2);
+    QVERIFY(QFile(testfile_path2).remove());
+
+    // We cannot reasonably redefine __FILE__, so we call the underlying function instead.
+    // __FILE__ may be absolute or relative path; test both.
+
+    // absolute:
+    QCOMPARE(QTest::qFindTestData(TESTFILE, qPrintable(app_path + "/fakesrc/fakefile.cpp"), __LINE__), testfile_path3);
+
+    // relative: (pretend that we were compiled within fakebuild directory, pointing at files in ../fakesrc)
+    QCOMPARE(QTest::qFindTestData(TESTFILE, "../fakesrc/fakefile.cpp", __LINE__, qPrintable(app_path + "/fakebuild")), testfile_path3);
+
+    QVERIFY(QFile(testfile_path3).remove());
+
+    // Note, this is expected to generate a warning.
+    // We can't use ignoreMessage, because the warning comes from testlib,
+    // not via a "normal" qWarning.  But it's OK, our caller (tst_selftests)
+    // will verify that the warning is printed.
+    QCOMPARE(QFINDTESTDATA(TESTFILE), QString());
+}
+
+QTEST_MAIN(FindTestData)
+#include "findtestdata.moc"
diff --git a/tests/auto/testlib/selftests/findtestdata/findtestdata.pro b/tests/auto/testlib/selftests/findtestdata/findtestdata.pro
new file mode 100644
index 0000000000..6e072aeb6f
--- /dev/null
+++ b/tests/auto/testlib/selftests/findtestdata/findtestdata.pro
@@ -0,0 +1,8 @@
+SOURCES += findtestdata.cpp
+QT = core testlib
+
+mac:CONFIG -= app_bundle
+CONFIG -= debug_and_release_target
+
+
+TARGET = findtestdata
diff --git a/tests/auto/testlib/selftests/findtestdata/qt.conf b/tests/auto/testlib/selftests/findtestdata/qt.conf
new file mode 100644
index 0000000000..f65543c63c
--- /dev/null
+++ b/tests/auto/testlib/selftests/findtestdata/qt.conf
@@ -0,0 +1,4 @@
+# This file does not need to contain anything.
+# Its mere presence will cause this directory to be treated as the
+# Qt install prefix.  The findtestdata test uses this to "fake" the
+# tests install path.