Lock file create and remove improvements (#2183)

* changed the locking function to better support multiple servers running at once and sharing the same config

* helper function testing now runs inside of container

Co-authored-by: Brennan Kinney <5098581+polarathene@users.noreply.github.com>

test/helper-functions.bats

@@ -0,0 +1,43 @@
+load 'test_helper/common'
+
+function setup() {
+    run_setup_file_if_necessary
+}
+
+function teardown() {
+    run_teardown_file_if_necessary
+}
+
+function setup_file() {
+    local PRIVATE_CONFIG
+    PRIVATE_CONFIG="$(duplicate_config_for_container .)"
+    docker run -d --name mail_helper_functions \
+        --cap-add=NET_ADMIN \
+        -v "${PRIVATE_CONFIG}":/tmp/docker-mailserver \
+        -v "$(pwd)/test/test-files":/tmp/docker-mailserver-test:ro \
+        -e ENABLE_FETCHMAIL=1 \
+        -e DMS_DEBUG=0 \
+        -h mail.my-domain.com -t "${NAME}"
+    wait_for_finished_setup_in_container mail_helper_functions
+}
+
+function teardown_file() {
+    docker rm -f mail_helper_functions
+}
+
+@test "first" {
+    skip 'this test must come first to reliably identify when to run setup_file'
+}
+
+@test "check helper-functions.sh: _sanitize_ipv4_to_subnet_cidr" {
+    run docker exec mail_helper_functions bash -c ". /usr/local/bin/helper-functions.sh; _sanitize_ipv4_to_subnet_cidr 255.255.255.255/0"
+    assert_output "0.0.0.0/0"
+    run docker exec mail_helper_functions bash -c ". /usr/local/bin/helper-functions.sh; _sanitize_ipv4_to_subnet_cidr 192.168.255.14/20"
+    assert_output "192.168.240.0/20"
+    run docker exec mail_helper_functions bash -c ". /usr/local/bin/helper-functions.sh; _sanitize_ipv4_to_subnet_cidr 192.168.255.14/32"
+    assert_output "192.168.255.14/32"
+}
+
+@test "last" {
+    skip 'this test is only there to reliably mark the end for the teardown_file'
+}