Solve Fetchmail imap idle issue (#10)

* Migrate PR#1730 from tomav/docker-mailserver repo to new
docker-mailserver/docker-mailserver repo
* Resolved review comments
* Moved counter increment to have consistency between fetchmail process
and fetchmail config files
* Added tests for new fetchmail option

Co-authored-by: Georg Lauterbach <44545919+aendeavor@users.noreply.github.com>

test/config/fetchmail.cf

@@ -3,3 +3,9 @@ poll pop3.example.com. with proto POP3
 	password 'secret'
 	is 'user2@domain.tld'
 	here options keep ssl
+	
+poll pop3-2.example.com. with proto POP3
+	user 'username' there with
+	password 'secret'
+	is 'user3@domain.tld'
+	here options keep ssl

test/mail_fetchmail_parallel.bats

@@ -0,0 +1,97 @@
+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="$(duplicate_config_for_container .)"
+    docker run -d --name mail_fetchmail_parallel \
+		-v "${PRIVATE_CONFIG}":/tmp/docker-mailserver \
+		-v "$(pwd)/test/test-files":/tmp/docker-mailserver-test:ro \
+		-e ENABLE_FETCHMAIL=1 \
+		-e FETCHMAIL_PARALLEL=1 \
+		--cap-add=NET_ADMIN \
+		-e DMS_DEBUG=0 \
+		-h mail.my-domain.com -t "${NAME}"
+    wait_for_finished_setup_in_container mail_fetchmail_parallel
+}
+
+function teardown_file() {
+    docker rm -f mail_fetchmail_parallel
+}
+
+@test "first" {
+  skip 'this test must come first to reliably identify when to run setup_file'
+}
+
+#
+# processes
+#
+
+@test "checking process: fetchmail 1 (fetchmail server enabled)" {
+  run docker exec mail_fetchmail_parallel /bin/bash -c "ps aux --forest | grep -v grep | grep '/usr/bin/fetchmail -f /etc/fetchmailrc.d/fetchmail-1.rc'"
+  assert_success
+}
+
+@test "checking process: fetchmail 2 (fetchmail server enabled)" {
+  run docker exec mail_fetchmail_parallel /bin/bash -c "ps aux --forest | grep -v grep | grep '/usr/bin/fetchmail -f /etc/fetchmailrc.d/fetchmail-2.rc'"
+  assert_success
+}
+
+#
+# fetchmail
+#
+
+@test "checking fetchmail: gerneral options in fetchmail-1.rc are loaded" {
+  run docker exec mail_fetchmail_parallel grep 'set syslog' /etc/fetchmailrc.d/fetchmail-1.rc
+  assert_success
+}
+
+@test "checking fetchmail: gerneral options in fetchmail-2.rc are loaded" {
+  run docker exec mail_fetchmail_parallel grep 'set syslog' /etc/fetchmailrc.d/fetchmail-2.rc
+  assert_success
+}
+
+@test "checking fetchmail: fetchmail-1.rc is loaded with pop3.example.com" {
+  run docker exec mail_fetchmail_parallel grep 'pop3.example.com' /etc/fetchmailrc.d/fetchmail-1.rc
+  assert_success
+}
+
+@test "checking fetchmail: fetchmail-1.rc is loaded without pop3-2.example.com" {
+  run docker exec mail_fetchmail_parallel grep 'pop3-2.example.com' /etc/fetchmailrc.d/fetchmail-1.rc
+  assert_failure
+}
+
+@test "checking fetchmail: fetchmail-2.rc is loaded without pop3.example.com" {
+  run docker exec mail_fetchmail_parallel grep 'pop3.example.com' /etc/fetchmailrc.d/fetchmail-2.rc
+  assert_failure
+}
+
+@test "checking fetchmail: fetchmail-2.rc is loaded with pop3-2.example.com" {
+  run docker exec mail_fetchmail_parallel grep 'pop3-2.example.com' /etc/fetchmailrc.d/fetchmail-2.rc
+  assert_success
+}
+
+#
+# supervisor
+#
+
+@test "checking restart of process: fetchmail-1" {
+  run docker exec mail_fetchmail_parallel /bin/bash -c "pkill fetchmail && sleep 10 && ps aux --forest | grep -v grep | grep '/usr/bin/fetchmail -f /etc/fetchmailrc.d/fetchmail-1.rc'"
+  assert_success
+}
+
+@test "checking restart of process: fetchmail-2" {
+  run docker exec mail_fetchmail_parallel /bin/bash -c "pkill fetchmail && sleep 10 && ps aux --forest | grep -v grep | grep '/usr/bin/fetchmail -f /etc/fetchmailrc.d/fetchmail-2.rc'"
+  assert_success
+}
+
+@test "last" {
+  skip 'this test is only there to reliably mark the end for the teardown_file'
+}