diff --git a/src/testlib/qsignalspy.cpp b/src/testlib/qsignalspy.cpp
index 9902122cb4d..116ce87c3eb 100644
--- a/src/testlib/qsignalspy.cpp
+++ b/src/testlib/qsignalspy.cpp
@@ -250,7 +250,8 @@ public:
 };
 
 QSignalSpy::QSignalSpy(ObjectSignal os)
-    : args(os.obj ? makeArgs(os.sig, os.obj) : QList<int>{})
+    : sig(os.sig.methodSignature()),
+      args(os.obj ? makeArgs(os.sig, os.obj) : QList<int>{})
 {
     if (!os.obj)
         return;
@@ -266,8 +267,6 @@ QSignalSpy::QSignalSpy(ObjectSignal os)
     }
 
     d_ptr = std::move(i);
-
-    sig = os.sig.methodSignature();
 }
 
 /*!
diff --git a/src/testlib/qsignalspy.h b/src/testlib/qsignalspy.h
index a5c960e3835..b8df2a4deb6 100644
--- a/src/testlib/qsignalspy.h
+++ b/src/testlib/qsignalspy.h
@@ -41,7 +41,7 @@ public:
         : QSignalSpy(verify(obj, signal)) {}
     Q_TESTLIB_EXPORT ~QSignalSpy();
 
-    inline bool isValid() const { return !sig.isEmpty(); }
+    bool isValid() const noexcept { return d_ptr != nullptr; }
     inline QByteArray signal() const { return sig; }
 
     bool wait(int timeout)
@@ -58,7 +58,7 @@ private:
     Q_TESTLIB_EXPORT void appendArgs(void **a);
 
     // the full, normalized signal name
-    QByteArray sig;
+    const QByteArray sig;
     // holds the QMetaType types for the argument list of the signal
     const QList<int> args;