Resolve VNC-226 Introduce $DEBUG variable in CI

.ci/helpers.sh

@@ -108,6 +108,17 @@ prepare_to_run_functional_tests() {
   prepare_functional_tests_source_and_cd_into_it
   prepare_s3_uploader
   prepare_kasmvnc_built_packages_to_replace_workspaces_image_packages
+  heed_debug_variable_and_toggle_debug_in_functional_tests
+}
+
+heed_debug_variable_and_toggle_debug_in_functional_tests() {
+  if [ -z "$CI" ]; then
+    return
+  fi
+
+  if [ "$DEBUG" = "true" ]; then
+    export KASMVNC_FUNC_TESTS_DEBUG=1
+  fi
 }
 
 install_packages_needed_for_functional_tests() {

.gitlab-ci.yml

@@ -3,6 +3,7 @@ services:
   - docker:dind
 
 variables:
+  DEBUG: true
   KASMVNC_COMMIT_ID: $CI_COMMIT_SHA
   GITLAB_SHARED_DIND_DIR: /builds/$CI_PROJECT_PATH/shared
   GIT_SUBMODULE_STRATEGY: recursive