diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index f96afb305c1f84eb94055bb3bf7f5b8b7922f1c1..3374def33af870a1e2a60e58b875183130c1984c 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,5 +1,3 @@
-# Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
-
 # List of the CI build stages.
 stages:
   - step-A
@@ -27,7 +25,7 @@ workflow:
 
 # TEMPLATES FOR BUILDING ON DIFFERENT PLATFORMS
 
-# Base template for all macOS jobs
+# general macOS job template
 .macos-template-job: &macos-job
   tags:
     - macos
@@ -43,7 +41,10 @@ workflow:
     - export CPPFLAGS="-I/usr/local/opt/expat/include"
     - export PATH="/usr/local/opt/qt5/bin:$PATH" # to make Qt5 discoverable by CMake
 
-# Base template for all Ubuntu jobs
+# NOTE
+# The Ubuntu package 'nlohmann-json-dev' is version 2.x, too old for us.
+# Thus, for GeoModelVisualization (GMEX), we now build nlohmann_json as part
+# of the build, by using the 'standalone' job only
 .ubuntu-template-job-default: &ubuntu-job
   image: gitlab-registry.cern.ch/geomodeldev/ubuntu-geant4-image:main-base
   rules:
diff --git a/CI/DockerfileFull b/CI/DockerfileFull
index bf50b397d014269c6b899fa75a27143a703c6d5d..79cb16a899b034e392d829f6e9a38e3d2c05fc04 100755
--- a/CI/DockerfileFull
+++ b/CI/DockerfileFull
@@ -2,12 +2,8 @@
 ARG BASEIMAGE=gitlab-registry.cern.ch/geomodeldev/ubuntu-geant4-image:main-base
 FROM ${BASEIMAGE}
 
-# Install GoogleTest
-# FIXME: we want to move this to the main image later
-RUN apt-get update && apt-get install -y libgtest-dev
-
 ### Compile then geo model
-COPY . /workdir/GeoModel_src/
+COPY . /workdir/GeoModel_src/ 
 RUN mkdir -p /workdir/build_geomodel/ && \   
     cd /workdir/build_geomodel/ && \
     . ~/.bashrc && \
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 11529c9b3f55021f8192adc7290fed422b8e5940..e747085ca71b79d5a625767de7e31a2eccd5dc6b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-# Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
+# Copyright (C) 2002-2023 CERN for the benefit of the ATLAS collaboration
 
 # === Preamble ===
 cmake_minimum_required(VERSION 3.16...3.26)
@@ -34,9 +34,6 @@ endif()
 include( SetupEigen3 )
 include( SetupXercesC )
 include( SetupJSON )
-# Add the GoogleTest framework, for tests
-find_package(GTest REQUIRED)
-include_directories(${GTEST_INCLUDE_DIRS})
 
 # Find the dependencies that the project always picks up from its environment.
 find_package( SQLite3 3.7.17 )
diff --git a/GeoModelIO/GeoModelDBManager/CMakeLists.txt b/GeoModelIO/GeoModelDBManager/CMakeLists.txt
index 37dabe13b3c1153fa62724784d4a6e1765236e19..513943cf47bcc58dc6f8647fbe8b233c7244f0c6 100644
--- a/GeoModelIO/GeoModelDBManager/CMakeLists.txt
+++ b/GeoModelIO/GeoModelDBManager/CMakeLists.txt
@@ -1,12 +1,11 @@
-# Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
+# Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
 ################################################################################
 # Package: GeoModelDBManager
 # author: Riccardo Maria BIANCHI @ CERN - 2017
 # major updates:
 # - R.M.Bianchi, 2018
-# - R.M.Bianchi, Nov 2020
-# - R.M.Bianchi, Apr 2024 -- Add CTest tests
-# - R.M.Bianchi, Feb 2025 -- Add GoogleTest support
+# - R.M.Bianvhi, Nov 2020
+# - R.M.Bianvhi, Apr 2024
 ################################################################################
 
 # Find the header and source files.
@@ -40,32 +39,7 @@ install( FILES ${HEADERS}
    DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/GeoModelDBManager
    COMPONENT Development )
 
-
-### --- Add Tests ---
-
-#++ Create a 'simple' unit test
 add_executable(test_create_db_file tests/test_create_db_file.cpp)
 target_link_libraries( test_create_db_file GeoModelIO::GeoModelDBManager)
 add_test(NAME testCreateDBFile
          COMMAND test_create_db_file)
-
-#++ Create a GoogleTest test, 
-#   and let CTest run all the sub-tests defined in it separately.
-#   NOTE: You can still use the standard CMake `add_test` function
-#         to declare the test; however, in that case, CTest will 
-#         run it as a whole and you will only get one line of output
-#         for all the tests in it togetehr. 
-#         While with the GTest method here below, you will get 
-#         one line of output for each actual test defined in the 
-#         'container' test program. 
-#         Therefore, for GTest tests it is advisable to use the
-#         approach below. 
-#
-# Create test executable
-add_executable(test_db_functions tests/test_db_functions.cpp)
-target_link_libraries(test_db_functions GeoModelDBManager GTest::GTest GTest::Main)
-# Register the test and let CTest discover 
-# all tests contained in it and run them separately
-include(GoogleTest)
-gtest_discover_tests(test_db_functions)
-
diff --git a/GeoModelIO/GeoModelDBManager/tests/test_create_db_file.cpp b/GeoModelIO/GeoModelDBManager/tests/test_create_db_file.cpp
index 6fb9c5fa5388f0550e7d03dfb894181b164094e3..970e18de7a8f9a009549d12bfb04cd3b692517be 100644
--- a/GeoModelIO/GeoModelDBManager/tests/test_create_db_file.cpp
+++ b/GeoModelIO/GeoModelDBManager/tests/test_create_db_file.cpp
@@ -22,7 +22,7 @@ int main(int argc, char *argv[])
     //------------------------------------------------------------------------------------//
     //  Open a geometry file
     //------------------------------------------------------------------------------------//
-    std::string path = "test_geometry.db";
+    std::string path = "geometry.db";
 
     // check if DB file exists. If not, return.
     // FIXME: TODO: this check should go in the 'GMDBManager' constructor.
diff --git a/GeoModelIO/GeoModelDBManager/tests/test_db_functions.cpp b/GeoModelIO/GeoModelDBManager/tests/test_db_functions.cpp
deleted file mode 100644
index 6bba7f476203b34e6f0deb7e09630d5ef19fdd04..0000000000000000000000000000000000000000
--- a/GeoModelIO/GeoModelDBManager/tests/test_db_functions.cpp
+++ /dev/null
@@ -1,64 +0,0 @@
-// GeoModel includes
-#include "GeoModelDBManager/GMDBManager.h"
-
-#include <gtest/gtest.h>
-#include <filesystem>
-
-class DatabaseTest : public ::testing::Test {
-protected:
-    std::string dbFile = "test_database.db";
-    std::unique_ptr<GMDBManager> dbManager{};
-
-    void SetUp() override {
-        // Remove any existing test database
-        if (std::filesystem::exists(dbFile)) {
-            std::filesystem::remove(dbFile);
-        }
-        
-        // open the DB connection
-        dbManager = std::make_unique<GMDBManager>(dbFile);
-        
-        // check the DB connection
-        if (dbManager->checkIsDBOpen())
-        {
-            std::cout << "OK! Database is open!" << std::endl;
-        }
-        else
-        {
-            std::cout << "Database ERROR!! Exiting..." << std::endl;
-            exit(EXIT_FAILURE);
-        }
-    }
-
-    void TearDown() override {
-        if (std::filesystem::exists(dbFile)) {
-            std::filesystem::remove(dbFile);
-        }
-    }
-};
-
-TEST_F(DatabaseTest, CreateDatabaseTest) {
-    // EXPECT_TRUE(dbManager->createDatabase());
-    EXPECT_TRUE(std::filesystem::exists(dbFile));
-}
-
-TEST_F(DatabaseTest, PopulateDatabaseTest) {
-    // ASSERT_TRUE(dbManager->createDatabase());
-    EXPECT_TRUE(dbManager->initDB());
-}
-
-// TEST_F(DatabaseTest, InsertDataTest) {
-//     ASSERT_TRUE(dbManager->createDatabase());
-//     ASSERT_TRUE(dbManager->initDB());
-
-//     EXPECT_TRUE(dbManager->insertData("key1", "value1"));
-// }
-
-// TEST_F(DatabaseTest, ReadDataTest) {
-//     ASSERT_TRUE(dbManager->createDatabase());
-//     ASSERT_TRUE(dbManager->populateDatabase());
-
-//     dbManager->insertData("key1", "value1");
-//     EXPECT_EQ(dbManager->readData("key1"), "value1");
-// }
-