Factor out JSON diff test helper and make it show something on Windows

autotests/extractorscriptenginetest.cpp

@@ -5,6 +5,7 @@
 */
 
 #include "config-kitinerary.h"
+#include "testhelpers.h"
 
 #include <KItinerary/ExtractorDocumentNode>
 #include <KItinerary/ExtractorDocumentNodeFactory>
@@ -16,7 +17,6 @@
 #include <QDebug>
 #include <QFile>
 #include <QJsonDocument>
-#include <QProcess>
 #include <QTest>
 
 using namespace KItinerary;
@@ -87,19 +87,7 @@ private Q_SLOTS:
         QFile ref(refFile);
         QVERIFY(ref.open(QFile::ReadOnly));
         const auto refResult = QJsonDocument::fromJson(ref.readAll()).array();
-
-        if (result != refResult) {
-            QFile failFile(refFile + QLatin1String(".fail"));
-            QVERIFY(failFile.open(QFile::WriteOnly));
-            failFile.write(QJsonDocument(result).toJson());
-            failFile.close();
-
-            QProcess proc;
-            proc.setProcessChannelMode(QProcess::ForwardedChannels);
-            proc.start(QStringLiteral("diff"), {QStringLiteral("-u"), refFile, failFile.fileName()});
-            QVERIFY(proc.waitForFinished());
-        }
-        QCOMPARE(result, refResult);
+        QVERIFY(Test::compareJson(refFile, result, refResult));
     }
 
     void testInfiniteLoop()

autotests/extractortest.cpp

@@ -6,6 +6,8 @@
 
 #include <config-kitinerary.h>
 
+#include "testhelpers.h"
+
 #include <KItinerary/ExtractorEngine>
 #include <KItinerary/ExtractorPostprocessor>
 #include <KItinerary/ExtractorValidator>
@@ -20,7 +22,6 @@
 #include <QJsonArray>
 #include <QJsonDocument>
 #include <QObject>
-#include <QProcess>
 #include <QTest>
 
 void initLocale()
@@ -154,19 +155,7 @@ private Q_SLOTS:
         QFile f(refFile);
         QVERIFY(f.open(QFile::ReadOnly));
         const auto refDoc = QJsonDocument::fromJson(f.readAll());
-        if (refDoc.array() != encodedResult) {
-            QFile failFile(refFile + QLatin1String(".fail"));
-            QVERIFY(failFile.open(QFile::WriteOnly));
-            failFile.write(QJsonDocument(encodedResult).toJson());
-            failFile.close();
-
-            QProcess proc;
-            proc.setProcessChannelMode(QProcess::ForwardedChannels);
-            proc.start(QStringLiteral("diff"), {QStringLiteral("-u"), refFile, failFile.fileName()});
-            QVERIFY(proc.waitForFinished());
-        }
-
-        QCOMPARE(refDoc.array(), encodedResult);
+        QVERIFY(Test::compareJson(refFile, encodedResult, refDoc.array()));
     }
 
     void testNegative()

autotests/testhelpers.h

+/*
+    SPDX-FileCopyrightText: 2019-2022 Volker Krause <vkrause@kde.org>
+    SPDX-License-Identifier: LGPL-2.0-or-later
+*/
+
+#ifndef TESTHELPERS_H
+#define TESTHELPERS_H
+
+#include <QFile>
+#include <QJsonDocument>
+#include <QProcess>
+#include <QTest>
+
+namespace Test {
+    template <typename T>
+    inline bool compareJson(const QString &refFile, const T &output, const T &ref)
+    {
+        if (output != ref) {
+#ifndef Q_OS_WIN
+            QFile failFile(refFile + QLatin1String(".fail"));
+            failFile.open(QFile::WriteOnly);
+            failFile.write(QJsonDocument(output).toJson());
+            failFile.close();
+
+            QProcess proc;
+            proc.setProcessChannelMode(QProcess::ForwardedChannels);
+            proc.start(QStringLiteral("diff"), {QStringLiteral("-u"), refFile, failFile.fileName()});
+            proc.waitForFinished();
+#else
+            qDebug().noquote() << "Got:" << QJsonDocument(output).toJson();
+            qDebug().noquote() << "Expected:" << QJsonDocument(ref).toJson();
+#endif
+            return false;
+        }
+        return true;
+    }
+}
+
+#endif