diff --git a/src/plugins/vcsbase/vcsbase.pro b/src/plugins/vcsbase/vcsbase.pro
index b433f817433..e256da05153 100644
--- a/src/plugins/vcsbase/vcsbase.pro
+++ b/src/plugins/vcsbase/vcsbase.pro
@@ -64,3 +64,5 @@ FORMS += commonsettingspage.ui \
     nicknamedialog.ui \
     cleandialog.ui \
     submiteditorwidget.ui
+
+equals(TEST, 1): DEFINES += "SRC_DIR=\\\"$$IDE_SOURCE_TREE\\\""
diff --git a/src/plugins/vcsbase/vcsbase.qbs b/src/plugins/vcsbase/vcsbase.qbs
index 857577a46a9..fc120227722 100644
--- a/src/plugins/vcsbase/vcsbase.qbs
+++ b/src/plugins/vcsbase/vcsbase.qbs
@@ -83,4 +83,6 @@ QtcPlugin {
         "wizard/vcsjsextension.cpp",
         "wizard/vcsjsextension.h",
     ]
+
+    cpp.defines: base.concat( testsEnabled ? ['SRC_DIR="' + project.ide_source_tree + '"'] : [] )
 }
diff --git a/src/plugins/vcsbase/vcsbaseeditor.cpp b/src/plugins/vcsbase/vcsbaseeditor.cpp
index cb1c238aba2..0925088a83b 100644
--- a/src/plugins/vcsbase/vcsbaseeditor.cpp
+++ b/src/plugins/vcsbase/vcsbaseeditor.cpp
@@ -1635,6 +1635,8 @@ void VcsBase::VcsBaseEditorWidget::testDiffFileResolving(const char *id)
     QFETCH(QByteArray, fileName);
     QTextDocument doc(QString::fromLatin1(header));
     QTextBlock block = doc.lastBlock();
+    // set source root for shadow builds
+    widget->setSource(QString::fromLatin1(SRC_DIR));
     QVERIFY(widget->fileNameFromDiffSpecification(block).endsWith(QString::fromLatin1(fileName)));
 
     delete editor;