diff --git a/roles/mail_server/tests/test_default.py b/roles/mail_server/tests/test_default.py
index ef04a32b8c6dc6cc2738e21edb2cf11d1c0c55c9..99320380e31e37353023abcaf90330ca84bd8ea1 100644
--- a/roles/mail_server/tests/test_default.py
+++ b/roles/mail_server/tests/test_default.py
@@ -1,12 +1,236 @@
+import re
+
 import testinfra.utils.ansible_runner
 
+
 testinfra_hosts = testinfra.utils.ansible_runner.AnsibleRunner(
-    '.molecule/ansible_inventory').get_hosts('all')
+    '.molecule/ansible_inventory').get_hosts(['parameters-mandatory', 'parameters-optiona'])
+
+
+def test_installed_packages(Package):
+    """
+    Tests if the necessary packages have been installed.
+    """
+
+    assert Package('rsync').is_installed
+    assert Package('dovecot-imapd').is_installed
+    assert Package('dovecot-ldap').is_installed
+    assert Package('dovecot-sieve').is_installed
+    assert Package('dovecot-managesieved').is_installed
+    assert Package('postfix').is_installed
+    assert Package('postfix-ldap').is_installed
+    assert Package('swaks').is_installed
+    assert Package('clamav-milter').is_installed
+
+
+def test_removed_packages(Package):
+    """
+    Tests if certain packages have been removed from the system.
+    """
+    assert not Package('exim4').is_installed
+
+
+def test_postfix_user(User):
+    """
+    Tests if Postfix user has been added to correct group for traversing the TLS
+    private key directory.
+    """
+
+    assert "ssl-cert" in User('postfix').groups
+
+
+def test_dovecot_user(User):
+    """
+    Tests if Dovecot user has been added to correct group for traversing the TLS
+    private key directory.
+    """
+
+    assert "ssl-cert" in User('dovecot').groups
+
+
+def test_clamav_milter_configuration(File):
+    """
+    Tests if ClamAV Milter configuration has been deployed correctly.
+    """
+
+    config = File('/etc/clamav/clamav-milter.conf')
+
+    assert config.is_file
+    assert config.user == 'root'
+    assert config.group == 'root'
+    assert config.mode == 0o644
+
+
+def test_clamav_milter(Command):
+    """
+    Tests if ClamAV milter is blocking viruses.
+    """
+
+    server_did_not_accept_mail = 26
+
+    eicar = 'X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*'
+
+    send_mail = Command("swaks --to john.doe@domain1 --server localhost --attach '%s'" % eicar)
+
+    assert send_mail.rc == server_did_not_accept_mail
+    assert 'Your message has been rejected due to a possible virus' in send_mail.stdout
+
+
+def test_postfix_chroot_directories(File):
+    """
+    Tests if Postfix chroot directories have been set-up with correct
+    permissions.
+    """
+
+    directory = File('/var/spool/postfix/var')
+    assert directory.is_directory
+    assert directory.user == 'root'
+    assert directory.group == 'root'
+    assert directory.mode == 0o755
+
+    directory = File('/var/spool/postfix/var/run')
+    assert directory.is_directory
+    assert directory.user == 'root'
+    assert directory.group == 'root'
+    assert directory.mode == 0o755
+
+    directory = File('/var/spool/postfix/var/run/clamav')
+    assert directory.is_directory
+    assert directory.user == 'clamav'
+    assert directory.group == 'clamav'
+    assert directory.mode == 0o755
+
+
+def test_ldap_tls_truststore_file(File):
+    """
+    Tests if the LDAP TLS truststore file has been deployed correctly.
+    """
+
+    tls_file = File('/etc/ssl/certs/mail_ldap_tls_truststore.pem')
+    assert tls_file.is_file
+    assert tls_file.user == 'root'
+    assert tls_file.group == 'root'
+    assert tls_file.mode == 0o644
+    assert tls_file.content == open("tests/data/x509/ca.cert.pem", "r").read().rstrip()
+
+    tls_file = File('/var/spool/postfix/etc/ssl/certs/mail_ldap_tls_truststore.pem')
+    assert tls_file.is_file
+    assert tls_file.user == 'root'
+    assert tls_file.group == 'root'
+    assert tls_file.mode == 0o644
+    assert tls_file.content == open("tests/data/x509/ca.cert.pem", "r").read().rstrip()
+
+
+def test_mailname_file(File):
+    """
+    Tests the system mail name file permissions.
+    """
+
+    mailname = File('/etc/mailname')
+
+    assert mailname.is_file
+    assert mailname.user == 'root'
+    assert mailname.group == 'root'
+    assert mailname.mode == 0o644
+
+
+def test_postfix_ldap_configuration_files(File):
+    """
+    Tests if Postfix LDAP configuration files have been deployed correctly.
+    """
+
+    for config_file_path in ['/etc/postfix/ldap-virtual-alias-maps.cf',
+                             '/etc/postfix/ldap-virtual-mailbox-domains.cf',
+                             '/etc/postfix/ldap-virtual-mailbox-maps.cf']:
+
+        config = File(config_file_path)
+        assert config.is_file
+        assert config.user == 'root'
+        assert config.group == 'postfix'
+        assert config.mode == 0o640
+
+
+def test_postfix_ldap_configuration(Command, Sudo):
+    """
+    Tests if LDAP configuration can be used to fetch correct query results.
+    """
+
+    with Sudo():
+
+        # Test for valid domains.
+        command = Command("postmap -q domain1 ldap:/etc/postfix/ldap-virtual-mailbox-domains.cf")
+        assert command.rc == 0
+        assert command.stdout == "domain1"
+
+        command = Command("postmap -q domain2 ldap:/etc/postfix/ldap-virtual-mailbox-domains.cf")
+        assert command.rc == 0
+        assert command.stdout == "domain2"
+
+        # Test for invalid domains.
+        command = Command("postmap -q domain3 ldap:/etc/postfix/ldap-virtual-mailbox-domains.cf")
+        assert command.rc == 1
+        assert command.stdout == ""
+
+        # Test for valid mail addresses.
+        command = Command("postmap -q 'john.doe@domain1' ldap:/etc/postfix/ldap-virtual-mailbox-maps.cf")
+        assert command.rc == 0
+        assert command.stdout == 'john.doe@domain1'
+
+        command = Command("postmap -q 'jane.doe@domain2' ldap:/etc/postfix/ldap-virtual-mailbox-maps.cf")
+        assert command.rc == 0
+        assert command.stdout == 'jane.doe@domain2'
+
+        # Test for invalid mail addresses.
+        command = Command("postmap -q 'jane.doe@domain1' ldap:/etc/postfix/ldap-virtual-mailbox-maps.cf")
+        assert command.rc == 1
+        assert command.stdout == ''
+
+        command = Command("postmap -q 'john.doe@domain2' ldap:/etc/postfix/ldap-virtual-mailbox-maps.cf")
+        assert command.rc == 1
+        assert command.stdout == ''
+
+        # Test for valid mail aliases.
+        command = Command("postmap -q postmaster@domain1 ldap:/etc/postfix/ldap-virtual-alias-maps.cf")
+        assert command.rc == 0
+        assert command.stdout == "john.doe@domain1"
+
+        command = Command("postmap -q webmaster@domain2 ldap:/etc/postfix/ldap-virtual-alias-maps.cf")
+        assert command.rc == 0
+        assert command.stdout == "jane.doe@domain2"
+
+        # Test for invalid mail aliases.
+        command = Command("postmap -q postmaster@domain2 ldap:/etc/postfix/ldap-virtual-alias-maps.cf")
+        assert command.rc == 1
+        assert command.stdout == ""
+
+        command = Command("postmap -q webmaster@domain1 ldap:/etc/postfix/ldap-virtual-alias-maps.cf")
+        assert command.rc == 1
+        assert command.stdout == ""
+
+
+def test_postfix_main_cf_file(File):
+    """
+    Tests Postfix main configuration file permissions.
+    """
+
+    config = File('/etc/postfix/main.cf')
+    assert config.is_file
+    assert config.user == 'root'
+    assert config.group == 'root'
+    assert config.mode == 0o644
+
 
+def test_postfix_delivery_to_dovecot(Command, File, Sudo):
+    """
+    Tests if mail received by Postfix is properly delivered to Dovecot.
+    """
 
-def test_hosts_file(File):
-    f = File('/etc/hosts')
+    # Virtual account.
+    send = Command('swaks --suppress-data --to john.doe@domain1 --server parameters-mandatory')
+    assert send.rc == 0
+    message_id = re.search('Ok: queued as (.*)', send.stdout).group(1)
 
-    assert f.exists
-    assert f.user == 'root'
-    assert f.group == 'root'
+    with Sudo():
+        mail_log = File('/var/log/mail.log')
+        pattern = "dovecot: lda\(john.doe@domain1\): msgid=<[^.]*.%s@[^>]*>: saved mail to INBOX" % message_id
+        assert re.search(pattern, mail_log.content) is not None