diff --git a/src/blackmisc/datacache.cpp b/src/blackmisc/datacache.cpp
index c15490dd2..33678d53e 100644
--- a/src/blackmisc/datacache.cpp
+++ b/src/blackmisc/datacache.cpp
@@ -99,10 +99,7 @@ namespace BlackMisc
 
     const QString &CDataCache::persistentStore()
     {
-        static const QString dir = QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation) +
-                                   "/org.swift-project/" +
-                                   CDirectoryUtils::normalizedApplicationDirectory() +
-                                   "/data/cache/core";
+        static const QString dir = getCacheRootDirectory() + "/data/cache/core";
         return dir;
     }
 
diff --git a/src/blackmisc/settingscache.cpp b/src/blackmisc/settingscache.cpp
index d3dd4b387..81366eb9f 100644
--- a/src/blackmisc/settingscache.cpp
+++ b/src/blackmisc/settingscache.cpp
@@ -26,10 +26,7 @@ namespace BlackMisc
 
     const QString &CSettingsCache::persistentStore()
     {
-        static const QString dir = QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation) +
-                "/org.swift-project/" +
-                CDirectoryUtils::normalizedApplicationDirectory() +
-                "/settings/core";
+        static const QString dir = getCacheRootDirectory() + "/settings/core";
         return dir;
     }
 
diff --git a/src/blackmisc/valuecache.cpp b/src/blackmisc/valuecache.cpp
index 8cb475dac..b1e5532af 100644
--- a/src/blackmisc/valuecache.cpp
+++ b/src/blackmisc/valuecache.cpp
@@ -11,6 +11,7 @@
 
 #include "blackmisc/valuecache.h"
 #include "blackmisc/atomicfile.h"
+#include "blackmisc/directoryutils.h"
 #include "blackmisc/identifier.h"
 #include "blackmisc/lockfree.h"
 #include "blackmisc/logcategory.h"
@@ -28,6 +29,7 @@
 #include <QList>
 #include <QMetaMethod>
 #include <QMutexLocker>
+#include <QStandardPaths>
 #include <QThread>
 #include <Qt>
 #include <algorithm>
@@ -46,6 +48,28 @@ namespace BlackMisc
     bool isSafeToIncrement(const T &value) { return value < std::numeric_limits<T>::max(); }
 
 
+    //! \private
+    std::pair<QString &, std::atomic<bool> &> getCacheRootDirectoryMutable()
+    {
+        static QString dir = QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation) +
+            "/org.swift-project/" + CDirectoryUtils::normalizedApplicationDirectory();
+        static std::atomic<bool> frozen { false };
+        return { dir, frozen };
+    }
+
+    void setMockCacheRootDirectory(const QString &dir)
+    {
+        Q_ASSERT_X(! getCacheRootDirectoryMutable().second, Q_FUNC_INFO, "Too late to call this function");
+        getCacheRootDirectoryMutable().first = dir;
+    }
+
+    const QString &CValueCache::getCacheRootDirectory()
+    {
+        getCacheRootDirectoryMutable().second = true;
+        return getCacheRootDirectoryMutable().first;
+    }
+
+
     ////////////////////////////////
     // CValueCachePacket
     ////////////////////////////////
diff --git a/src/blackmisc/valuecache.h b/src/blackmisc/valuecache.h
index c00e268cc..9df45ab49 100644
--- a/src/blackmisc/valuecache.h
+++ b/src/blackmisc/valuecache.h
@@ -48,6 +48,13 @@ namespace BlackMisc
 {
     class CLogCategoryList;
 
+    /*!
+     * Overwrite the default root directory for cache and settings, for testing purposes.
+     *
+     * May not be called after any cache or settings objects have been constructed.
+     */
+    BLACKMISC_EXPORT void setMockCacheRootDirectory(const QString &path);
+
     /*!
      * Value class used for signalling changed values in the cache.
      */
@@ -280,6 +287,9 @@ namespace BlackMisc
         //! \threadsafe
         qint64 getTimestampSync(const QString &key) { return std::get<1>(getValue(key)); }
 
+        //! \private
+        static const QString &getCacheRootDirectory();
+
     private:
         friend class Private::CValuePage;
         struct Element;