itest: make parallel itest runner for litd itests

Makefile

@@ -228,6 +228,13 @@ itest-parallel: build-itest db-instance
 	EXEC_SUFFIX=$(EXEC_SUFFIX) scripts/itest_parallel.sh $(ITEST_PARALLELISM) $(NUM_ITEST_TRANCHES) $(TEST_FLAGS) $(ITEST_FLAGS)
 	$(COLLECT_ITEST_COVERAGE)
 
+#? itest-litd-parallel: Build and run integration tests in parallel mode, running up to ITEST_PARALLELISM test tranches in parallel (default 4)
+itest-litd-parallel: build-itest db-instance
+	@$(call print, "Running tests")
+	rm -rf itest/*.log itest/.logs-*; date
+	EXEC_SUFFIX=$(EXEC_SUFFIX) scripts/itest_litd_parallel.sh $(ITEST_PARALLELISM) $(NUM_ITEST_TRANCHES) $(TEST_FLAGS) $(ITEST_FLAGS)
+	$(COLLECT_ITEST_COVERAGE)
+
 #? itest-clean: Kill all running itest processes
 itest-clean:
 	@$(call print, "Cleaning old itest processes")

scripts/itest_litd_parallel.sh

@@ -0,0 +1,37 @@
+#!/bin/bash
+
+# Get all the variables.
+PROCESSES=$1
+TRANCHES=$2
+TEST_FLAGS=$3
+ITEST_FLAGS=$4
+
+# Create a variable to hold the final exit code.
+exit_code=0
+
+# Run commands using xargs in parallel and capture their PIDs
+pids=()
+for ((i=0; i<PROCESSES; i++)); do 
+    scripts/itest_litd_part.sh $i $TRANCHES $TEST_FLAGS $ITEST_FLAGS &
+    pids+=($!)
+done
+
+
+# Wait for the processes created by xargs to finish.
+for pid in "${pids[@]}"; do
+    wait $pid
+
+    # Once finished, grab its exit code.
+    current_exit_code=$?
+
+    # Overwrite the exit code if current itest doesn't return 0.
+    if [ $current_exit_code -ne 0 ]; then
+        # Only write the exit code of the first failing itest.
+        if [ $exit_code -eq 0 ]; then
+            exit_code=$current_exit_code
+        fi
+    fi
+done
+
+# Exit with the exit code of the first failing itest or 0.
+exit $exit_code