diff --git a/compiler/tests-common/tests/org/jetbrains/kotlin/fir/AbstractFirBaseDiagnosticsTest.kt b/compiler/tests-common/tests/org/jetbrains/kotlin/fir/AbstractFirBaseDiagnosticsTest.kt
index 256f4ce975e..509422e5152 100644
--- a/compiler/tests-common/tests/org/jetbrains/kotlin/fir/AbstractFirBaseDiagnosticsTest.kt
+++ b/compiler/tests-common/tests/org/jetbrains/kotlin/fir/AbstractFirBaseDiagnosticsTest.kt
@@ -90,6 +90,7 @@ abstract class AbstractFirBaseDiagnosticsTest : BaseDiagnosticsTest() {
                 moduleFiles.mapNotNull { it.ktFile })
             FirJavaModuleBasedSession.create(info, sessionProvider, scope).also {
                 registerFirExtensions(it.extensionService)
+                configureSession(it)
             }
         }
 
@@ -331,4 +332,6 @@ abstract class AbstractFirBaseDiagnosticsTest : BaseDiagnosticsTest() {
         }
         return result
     }
+
+    protected open fun configureSession(session: FirSession) {}
 }
\ No newline at end of file