diff --git a/.gitignore b/.gitignore
index 7808c4b..140af95 100644
--- a/.gitignore
+++ b/.gitignore
@@ -26,6 +26,18 @@ pip-log.txt
 .tox
 nosetests.xml
 
+# GPG-Mailgate test files
+test/logs
+test/tmp
+test/gpg-mailgate.conf
+test/keyhome/random_seed
+
+# Emacs files
+*~
+TAGS
+TAGS-Python
+TAGS-PHP
+
 # Translations
 *.mo
 
diff --git a/GnuPG/__init__.py b/GnuPG/__init__.py
index c9bbee0..540622e 100644
--- a/GnuPG/__init__.py
+++ b/GnuPG/__init__.py
@@ -23,9 +23,20 @@ import subprocess
 import shutil
 import random
 import string
+import sys
+
+
+LINE_FINGERPRINT = 'fpr'
+LINE_USER_ID = 'uid'
+
+POS_FINGERPRINT = 9
+
+def build_command(key_home, *args, **kwargs):
+	cmd = ["gpg", '--homedir', key_home] + list(args)
+	return cmd
 
 def private_keys( keyhome ):
-	cmd = ['/usr/bin/gpg', '--homedir', keyhome, '--list-secret-keys', '--with-colons']
+	cmd = build_command(keyhome, '--list-secret-keys', '--with-colons')
 	p = subprocess.Popen( cmd, stdin=None, stdout=subprocess.PIPE, stderr=subprocess.PIPE )
 	p.wait()
 	keys = dict()
@@ -39,17 +50,24 @@ def private_keys( keyhome ):
 	return keys
 
 def public_keys( keyhome ):
-	cmd = ['/usr/bin/gpg', '--homedir', keyhome, '--list-keys', '--with-colons']
+	cmd = build_command(keyhome, '--list-keys', '--with-colons')
 	p = subprocess.Popen( cmd, stdin=None, stdout=subprocess.PIPE, stderr=subprocess.PIPE )
 	p.wait()
+
 	keys = dict()
+	fingerprint = None
+	email = None
 	for line in p.stdout.readlines():
-		if line[0:3] == 'uid' or line[0:3] == 'pub':
+		if line[0:3] == LINE_FINGERPRINT:
+			fingerprint = line.split(':')[POS_FINGERPRINT]
+		if line[0:3] == LINE_USER_ID:
 			if ('<' not in line or '>' not in line):
 				continue
 			email = line.split('<')[1].split('>')[0]
-			fingerprint = line.split(':')[4]
+		if not (fingerprint is None or email is None):
 			keys[fingerprint] = email
+			fingerprint = None
+			email = None
 	return keys
 
 # confirms a key has a given email address
@@ -64,7 +82,7 @@ def confirm_key( content, email ):
 	os.mkdir(tmpkeyhome)
 	localized_env = os.environ.copy()
 	localized_env["LANG"] = "C"
-	p = subprocess.Popen( ['/usr/bin/gpg', '--homedir', tmpkeyhome, '--import', '--batch'], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, env=localized_env )
+	p = subprocess.Popen( build_command(tmpkeyhome, '--import', '--batch'), stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, env=localized_env )
 	result = p.communicate(input=content)[1]
 	confirmed = False
 
@@ -83,7 +101,7 @@ def confirm_key( content, email ):
 
 # adds a key and ensures it has the given email address
 def add_key( keyhome, content ):
-	p = subprocess.Popen( ['/usr/bin/gpg', '--homedir', keyhome, '--import', '--batch'], stdin=subprocess.PIPE, stdout=subprocess.PIPE,stderr=subprocess.PIPE )
+	p = subprocess.Popen( build_command(keyhome, '--import', '--batch'), stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE )
 	p.communicate(input=content)
 	p.wait()
 
@@ -93,7 +111,7 @@ def delete_key( keyhome, email ):
 
 	if result[1]:
 		# delete all keys matching this email address
-		p = subprocess.Popen( ['/usr/bin/gpg', '--homedir', keyhome, '--delete-key', '--batch', '--yes', result[1]], stdin=None, stdout=subprocess.PIPE, stderr=subprocess.PIPE )
+		p = subprocess.Popen( build_command(keyhome, '--delete-key', '--batch', '--yes', result[1]), stdin=None, stdout=subprocess.PIPE, stderr=subprocess.PIPE )
 		p.wait()
 		return True
 
@@ -117,7 +135,7 @@ class GPGEncryptor:
 		return (encdata, p.returncode)
 
 	def _command(self):
-		cmd = ["/usr/bin/gpg", "--trust-model", "always", "--homedir", self._keyhome, "--batch", "--yes", "--pgp7", "--no-secmem-warning", "-a", "-e"]
+		cmd = build_command(self._keyhome, "--trust-model", "always", "--batch", "--yes", "--pgp7", "--no-secmem-warning", "-a", "-e")
 
 		# add recipients
 		for recipient in self._recipients:
@@ -145,6 +163,4 @@ class GPGDecryptor:
 		return (decdata, p.returncode)
 
 	def _command(self):
-		cmd = ["/usr/bin/gpg", "--trust-model", "always", "--homedir", self._keyhome, "--batch", "--yes", "--no-secmem-warning", "-a", "-d"]
-
-		return cmd
\ No newline at end of file
+		return build_command(self._keyhome, "--trust-model", "always", "--batch", "--yes", "--no-secmem-warning", "-a", "-d")
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..a14332a
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,32 @@
+PYTHON = python2.7
+
+.PHONY: test pre-clean clean
+
+#
+# Run a set of end-to-end tests.
+#
+# Test scenarios are described and configured by the test/e2e.ini
+# file.  Basically this is just a script that feeds GPG Mailgate with
+# known input and checks whether output meets expectations.
+#
+test: test/tmp test/logs pre-clean
+	$(PYTHON) test/e2e_test.py
+
+#
+# Run unit tests
+#
+unittest:
+	$(PYTHON) -m unittest discover -s test
+
+pre-clean:
+	rm -fv test/gpg-mailgate.conf
+	rm -f test/logs/*.log
+
+test/tmp:
+	mkdir test/tmp
+
+test/logs:
+	mkdir test/logs
+
+clean: pre-clean
+	rm -rfv test/tmp test/logs
diff --git a/doc/testing.md b/doc/testing.md
new file mode 100644
index 0000000..a462b0f
--- /dev/null
+++ b/doc/testing.md
@@ -0,0 +1,31 @@
+# Testing
+
+First tests have been set up to cover GPG Mailgate with at least basic test
+that would be easy to run.  The tests are called "end-to-end", meaning that we
+feed some input to GPG Mailgate and inspect the output.
+
+## Running tests
+
+To run tests, use command `make test` or `make unittest`.
+
+Tests produce some helpful logs, so inspect contents of `test/logs` directory
+if something goes wrong.
+
+## Key building blocks
+
+- *Test Script* (`test/e2e_test.py`) that orchestrates the other components.
+  It performs test cases described in the *Test Configuration*.  It spawns
+  *Test Mail Relay* and *GPG Mailgate* in appropriate order.
+- *Test Mail Relay* (`test/relay.py`), a simplistic mail daemon that only
+  supports the happy path.  It accepts a mail message and prints it to
+  stdandard output.
+- *Test Configuration* (`test/e2e.ini`) specifies test cases: their input,
+  expected results and helpful documentation.  It also specifies the port that
+  the *Test Mail Relay* should listen on.
+
+## Limitations
+
+Currently tests only check if the message has been encrypted, without
+verifying that the correct key has been used.  That's because we don't know
+(yet) how to have a reproducible encrypted message.  Option
+`--faked-system-time` wasn't enough to produce identical output.
diff --git a/gpg-mailgate.py b/gpg-mailgate.py
index 9830262..b39c786 100755
--- a/gpg-mailgate.py
+++ b/gpg-mailgate.py
@@ -39,9 +39,14 @@ import traceback
 from M2Crypto import BIO, Rand, SMIME, X509
 from email.mime.message import MIMEMessage
 
+# Environment variable name we read to retrieve configuration path.  This is to
+# enable non-root users to set up and run GPG Mailgate and to make the software
+# testable.
+CONFIG_PATH_ENV = "GPG_MAILGATE_CONFIG"
+
 # Read configuration from /etc/gpg-mailgate.conf
 _cfg = RawConfigParser()
-_cfg.read('/etc/gpg-mailgate.conf')
+_cfg.read(os.getenv(CONFIG_PATH_ENV, '/etc/gpg-mailgate.conf'))
 cfg = dict()
 for sect in _cfg.sections():
 	cfg[sect] = dict()
diff --git a/test/certs/.keep b/test/certs/.keep
new file mode 100644
index 0000000..e69de29
diff --git a/test/e2e.ini b/test/e2e.ini
new file mode 100644
index 0000000..2d6fb0b
--- /dev/null
+++ b/test/e2e.ini
@@ -0,0 +1,55 @@
+#
+#	gpg-mailgate
+#
+#	This file is part of the gpg-mailgate source code.
+#
+#	gpg-mailgate is free software: you can redistribute it and/or modify
+#	it under the terms of the GNU General Public License as published by
+#	the Free Software Foundation, either version 3 of the License, or
+#	(at your option) any later version.
+#
+#	gpg-mailgate source code is distributed in the hope that it will be useful,
+#	but WITHOUT ANY WARRANTY; without even the implied warranty of
+#	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+#	GNU General Public License for more details.
+#
+#	You should have received a copy of the GNU General Public License
+#	along with gpg-mailgate source code. If not, see <http://www.gnu.org/licenses/>.
+#
+
+# NOTE: We use <key>:<value> syntax, because some values contain
+# colons and that is default ConfigParser key-value separator.
+
+[relay]
+port: 2500
+script: test/relay.py
+
+[dirs]
+keys: test/keyhome
+certs: test/certs
+
+[tests]
+# Number of "test-*" sections in this file, describing test cases.
+cases: 3
+e2e_log: test/logs/e2e.log
+e2e_log_format: %(asctime)s %(pathname)s:%(lineno)d %(levelname)s [%(funcName)s] %(message)s
+e2e_log_datefmt: %Y-%m-%d %H:%M:%S
+lacre_log: test/logs/gpg-mailgate.log
+
+[case-1]
+descr: Clear text message to a user without a key
+to: carlos@disposlab
+in: test/msgin/clear2clear.msg
+out: Body of the message.
+
+[case-2]
+descr: Clear text message to a user with an RSA key
+to: alice@disposlab
+in: test/msgin/clear2rsa.msg
+out: -----BEGIN PGP MESSAGE-----
+
+[case-3]
+descr: Clear text message to a user with an Ed25519 key
+to: bob@disposlab
+in: test/msgin/clear2ed.msg
+out: -----BEGIN PGP MESSAGE-----
diff --git a/test/e2e_test.py b/test/e2e_test.py
new file mode 100644
index 0000000..d53d6d9
--- /dev/null
+++ b/test/e2e_test.py
@@ -0,0 +1,149 @@
+#!/usr/local/bin/python2
+
+#
+#	gpg-mailgate
+#
+#	This file is part of the gpg-mailgate source code.
+#
+#	gpg-mailgate is free software: you can redistribute it and/or modify
+#	it under the terms of the GNU General Public License as published by
+#	the Free Software Foundation, either version 3 of the License, or
+#	(at your option) any later version.
+#
+#	gpg-mailgate source code is distributed in the hope that it will be useful,
+#	but WITHOUT ANY WARRANTY; without even the implied warranty of
+#	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+#	GNU General Public License for more details.
+#
+#	You should have received a copy of the GNU General Public License
+#	along with gpg-mailgate source code. If not, see <http://www.gnu.org/licenses/>.
+#
+
+import os
+import sys
+
+import difflib
+
+import ConfigParser
+import logging
+
+from time import sleep
+
+RELAY_SCRIPT = "test/relay.py"
+CONFIG_FILE = "test/gpg-mailgate.conf"
+
+PYTHON_BIN = "python2.7"
+
+def build_config(config):
+    cp = ConfigParser.ConfigParser()
+
+    cp.add_section("logging")
+    cp.set("logging", "file", config["log_file"])
+    cp.set("logging", "verbose", "yes")
+
+    cp.add_section("gpg")
+    cp.set("gpg", "keyhome", config["gpg_keyhome"])
+
+    cp.add_section("smime")
+    cp.set("smime", "cert_path", config["smime_certpath"])
+
+    cp.add_section("relay")
+    cp.set("relay", "host", "localhost")
+    cp.set("relay", "port", config["port"])
+
+    cp.add_section("enc_keymap")
+    cp.set("enc_keymap", "alice@disposlab", "1CD245308F0963D038E88357973CF4D9387C44D7")
+    cp.set("enc_keymap", "bob@disposlab", "19CF4B47ECC9C47AFA84D4BD96F39FDA0E31BB67")
+
+    logging.debug("Created config with keyhome=%s, cert_path=%s and relay at port %d" %
+                  (config["gpg_keyhome"], config["smime_certpath"], config["port"]))
+    return cp
+
+def write_test_config(outfile, **config):
+    logging.debug("Generating configuration with %s" % repr(config))
+
+    out = open(outfile, "w+")
+    cp = build_config(config)
+    cp.write(out)
+    out.close()
+
+    logging.debug("Wrote configuration to %s" % outfile)
+
+def load_file(name):
+	f = open(name, 'r')
+	contents = f.read()
+	f.close()
+
+	return contents
+
+def report_result(message_file, expected, test_output):
+    status = None
+    if expected in test_output:
+        status = "Success"
+    else:
+        status = "Failure"
+
+    print message_file.ljust(30), status
+
+def execute_e2e_test(case_name, config, config_path):
+    """Read test case configuration from config and run that test case.
+
+    Parameter case_name should refer to a section in test
+    config file.  Each of these sections should contain
+    following properties: 'descr', 'to', 'in' and 'out'.
+    """
+
+    test_command = "GPG_MAILGATE_CONFIG=%s %s gpg-mailgate.py %s < %s" % (
+        config_path,
+        PYTHON_BIN,
+        config.get(case_name, "to"),
+        config.get(case_name, "in"))
+    result_command = "%s %s %d" % (PYTHON_BIN, config.get("relay", "script"), config.getint("relay", "port"))
+
+    logging.debug("Spawning relay: '%s'" % (result_command))
+    pipe = os.popen(result_command, 'r')
+
+    logging.debug("Spawning GPG-Lacre: '%s'" % (test_command))
+    msgin = os.popen(test_command, 'w')
+    msgin.write(load_file(config.get(case_name, "in")))
+    msgin.close()
+
+    testout = pipe.read()
+    pipe.close()
+
+    logging.debug("Read %d characters of test output: '%s'" % (len(testout), testout))
+
+    report_result(config.get(case_name, "in"), config.get(case_name, "out"), testout)
+
+def load_test_config():
+    cp = ConfigParser.ConfigParser()
+    cp.read("test/e2e.ini")
+
+    return cp
+
+
+config = load_test_config()
+
+logging.basicConfig(filename	= config.get("tests", "e2e_log"),
+                    # Get raw values of log and date formats because they
+                    # contain %-sequences and we don't want them to be expanded
+                    # by the ConfigParser.
+                    format		= config.get("tests", "e2e_log_format", True),
+                    datefmt		= config.get("tests", "e2e_log_datefmt", True),
+                    level		= logging.DEBUG)
+
+config_path = os.getcwd() + "/" + CONFIG_FILE
+
+write_test_config(config_path,
+                  port				= config.getint("relay", "port"),
+                  gpg_keyhome		= config.get("dirs", "keys"),
+                  smime_certpath	= config.get("dirs", "certs"),
+                  log_file			= config.get("tests", "lacre_log"))
+
+for case_no in range(1, config.getint("tests", "cases")+1):
+    case_name = "case-%d" % (case_no)
+    logging.info("Executing %s: %s", case_name, config.get(case_name, "descr"))
+
+    execute_e2e_test(case_name, config, config_path)
+
+print "See diagnostic output for details. Tests: '%s', Lacre: '%s'" % (config.get("tests", "e2e_log"), config.get("tests", "lacre_log"))
diff --git a/test/keyhome/crls.d/DIR.txt b/test/keyhome/crls.d/DIR.txt
new file mode 100644
index 0000000..2a29a47
--- /dev/null
+++ b/test/keyhome/crls.d/DIR.txt
@@ -0,0 +1 @@
+v:1:
diff --git a/test/keyhome/pubring.kbx b/test/keyhome/pubring.kbx
new file mode 100644
index 0000000..83e1be1
Binary files /dev/null and b/test/keyhome/pubring.kbx differ
diff --git a/test/keyhome/tofu.db b/test/keyhome/tofu.db
new file mode 100644
index 0000000..16104b5
Binary files /dev/null and b/test/keyhome/tofu.db differ
diff --git a/test/keyhome/trustdb.gpg b/test/keyhome/trustdb.gpg
new file mode 100644
index 0000000..7691303
Binary files /dev/null and b/test/keyhome/trustdb.gpg differ
diff --git a/test/msgin/clear2clear.msg b/test/msgin/clear2clear.msg
new file mode 100644
index 0000000..ae577d1
--- /dev/null
+++ b/test/msgin/clear2clear.msg
@@ -0,0 +1,5 @@
+From: Dave <dave@localhost>
+To: Carlos <carlos@localhost>
+Subject: Test
+
+Body of the message.
diff --git a/test/msgin/clear2ed.msg b/test/msgin/clear2ed.msg
new file mode 100644
index 0000000..63b6c66
--- /dev/null
+++ b/test/msgin/clear2ed.msg
@@ -0,0 +1,5 @@
+From: Dave <dave@localhost>
+To: Bob <bob@localhost>
+Subject: Test
+
+Body of the message.
diff --git a/test/msgin/clear2rsa.msg b/test/msgin/clear2rsa.msg
new file mode 100644
index 0000000..9dfd134
--- /dev/null
+++ b/test/msgin/clear2rsa.msg
@@ -0,0 +1,5 @@
+From: Dave <dave@localhost>
+To: Alice <alice@localhost>
+Subject: Test
+
+Body of the message.
diff --git a/test/relay.py b/test/relay.py
new file mode 100644
index 0000000..01b93d4
--- /dev/null
+++ b/test/relay.py
@@ -0,0 +1,82 @@
+#!/usr/local/bin/python2
+#
+# This quick-and-dirty script supports only the happy case of SMTP session,
+# i.e. what gpg-mailgate/gpg-lacre needs to deliver encrypted email.
+#
+# It listens on the port given as the only command-line argument and consumes a
+# message, then prints it to standard output.  The goal is to be able to
+# compare that output with expected clear-text or encrypted message body.
+#
+
+import sys
+import socket
+
+
+EXIT_UNAVAILABLE = 1
+
+BUFFER_SIZE = 4096
+EOM = "\r\n.\r\n"
+LAST_LINE = -3
+
+
+def welcome(msg):
+	return "220 %s\r\n" % (msg)
+
+def ok(msg = "OK"):
+	return "250 %s\r\n" % (msg)
+
+def bye():
+	return "251 Bye"
+
+def provide_message():
+	return "354 Enter a message, ending it with a '.' on a line by itself\r\n"
+
+def receive_and_confirm(session):
+	session.recv(BUFFER_SIZE)
+	session.sendall(ok())
+
+def serve(port):
+	s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+	try:
+		s.bind(('', port))
+		s.listen(1)
+	except socket.error, e:
+		print "Cannot connect", e
+		sys.exit(EXIT_UNAVAILABLE)
+
+	(conn, addr) = s.accept()
+	conn.sendall(welcome("TEST SERVER"))
+
+	receive_and_confirm(conn)				# Ignore HELO/EHLO
+	receive_and_confirm(conn)				# Ignore sender address
+	receive_and_confirm(conn)				# Ignore recipient address
+
+	data = conn.recv(BUFFER_SIZE)
+	conn.sendall(provide_message())
+
+	# Consume until we get <CR><LF>.<CR><LF>, the end-of-message marker.
+	message = ''
+	while not message.endswith(EOM):
+		message += conn.recv(BUFFER_SIZE)
+	conn.sendall(ok("OK, id=test"))
+
+	conn.recv(BUFFER_SIZE)
+	conn.sendall(bye())
+
+	conn.close()
+
+	# Trim EOM marker as we're only interested in the message body.
+	return message[:-len(EOM)]
+
+def error(msg):
+	print "ERROR: %s" % (msg)
+	sys.exit(1)
+
+
+if len(sys.argv) < 2:
+	error("Usage: relay.py PORT_NUMBER")
+
+port = int(sys.argv[1])
+body = serve(port)
+
+print body
diff --git a/test/test_gnupg.py b/test/test_gnupg.py
new file mode 100644
index 0000000..5712acd
--- /dev/null
+++ b/test/test_gnupg.py
@@ -0,0 +1,16 @@
+import GnuPG
+
+import unittest
+
+class GnuPGUtilitiesTest(unittest.TestCase):
+	def test_build_default_command(self):
+		cmd = GnuPG.build_command("test/keyhome")
+		self.assertEqual(cmd, ["gpg", "--homedir", "test/keyhome"])
+
+	def test_build_command_extended_with_args(self):
+		cmd = GnuPG.build_command("test/keyhome", "--foo", "--bar")
+		self.assertEqual(cmd, ["gpg", "--homedir", "test/keyhome", "--foo", "--bar"])
+
+
+if __name__ == '__main__':
+	unittest.main()