AutoTest: Add gtest filter mode

This adds another grouping mode to the gtest framework based on
gtest filtering. You can now specify a filter that will be used
to group the gtest tree items into matching and non-matching
tests.

Change-Id: Iaf0e55c9e57e2720f4fa84ab4b51ecaeb614df88
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/autotest/gtest/gtest_utils.cpp

@@ -25,6 +25,7 @@
 
 #include "gtest_utils.h"
 
+#include <QRegularExpression>
 #include <QStringList>
 
 namespace Autotest {
@@ -51,6 +52,17 @@ bool isGTestTyped(const QString &macro)
     return macro == QStringLiteral("TYPED_TEST") || macro == QStringLiteral("TYPED_TEST_P");
 }
 
+bool isValidGTestFilter(const QString &filterExpression)
+{
+    // this still is not a 100% validation - but a compromise
+    // - numbers after '.' should get prohibited
+    // - more than one '.' inside a single filter should be prohibited
+    static const QRegularExpression regex("^(:*([_a-zA-Z*.?][_a-zA-Z0-9*.?]*:*)*)?"
+                                          "(-(:*([_a-zA-Z*.?][_a-zA-Z0-9*.?]*:*)*)?)?$");
+
+    return regex.match(filterExpression).hasMatch();
+}
+
 } // namespace GTestUtils
 } // namespace Internal
 } // namespace Autotest