fix: use current_dir in test_spies_work_in_parallel

Author: Chemaclass

tests/acceptance/parallel_spy_parallel_test.sh

@@ -1,9 +1,10 @@
 #!/usr/bin/env bash
+# shellcheck disable=SC2155
 set -euo pipefail
 
 function test_spies_work_in_parallel() {
-  local file1=tests/acceptance/fixtures/test_parallel_spy_file1.sh
-  local file2=tests/acceptance/fixtures/test_parallel_spy_file2.sh
+  local file1="$(current_dir)/fixtures/test_parallel_spy_file1.sh"
+  local file2="$(current_dir)/fixtures/test_parallel_spy_file2.sh"
 
   ./bashunit --parallel "$file1" "$file2"
   assert_successful_code