diff --git a/test/io/config.py b/test/io/config.py
new file mode 100644
index 000000000..6cb63af14
--- /dev/null
+++ b/test/io/config.py
@@ -0,0 +1,54 @@
+import os
+import pathlib
+import shutil
+import signal
+
+import pytest
+import yaml
+
+
+BASEDIR = pathlib.Path(os.path.realpath(__file__)).parent
+CONFIGSDIR = BASEDIR / "configs"
+FIXTURES = yaml.load((BASEDIR / "fixtures.yaml").read_text(), Loader=yaml.Loader)
+POSTGREST_BIN = shutil.which("postgrest")
+SECRET = "reallyreallyreallyreallyverysafe"
+
+
+@pytest.fixture
+def dburi():
+    "Postgres database connection URI."
+    dbname = os.environ["PGDATABASE"]
+    host = os.environ["PGHOST"]
+    user = os.environ["PGUSER"]
+    return f"postgresql://?dbname={dbname}&host={host}&user={user}".encode()
+
+
+@pytest.fixture
+def baseenv():
+    "Base environment to connect to PostgreSQL"
+    return {
+        "PGDATABASE": os.environ["PGDATABASE"],
+        "PGHOST": os.environ["PGHOST"],
+        "PGUSER": os.environ["PGUSER"],
+    }
+
+
+@pytest.fixture
+def defaultenv(baseenv):
+    "Default environment for PostgREST."
+    return {
+        **baseenv,
+        "PGRST_DB_CONFIG": "true",
+        "PGRST_LOG_LEVEL": "info",
+        "PGRST_DB_POOL": "1",
+    }
+
+
+def hpctixfile():
+    "Returns an individual filename for each test, if the HPCTIXFILE environment variable is set."
+    if "HPCTIXFILE" not in os.environ:
+        return ""
+
+    tixfile = pathlib.Path(os.environ["HPCTIXFILE"])
+    test = hash(os.environ["PYTEST_CURRENT_TEST"])
+    return tixfile.with_suffix(f".{test}.tix")
diff --git a/test/io/postgrest.py b/test/io/postgrest.py
new file mode 100644
index 000000000..30a4c1ec9
--- /dev/null
+++ b/test/io/postgrest.py
@@ -0,0 +1,170 @@
+"Fixtures to run PostgREST as a server."
+
+import contextlib
+import dataclasses
+import os
+import pathlib
+import socket
+import subprocess
+import tempfile
+import time
+import urllib.parse
+
+import pytest
+import requests
+import requests_unixsocket
+
+from config import *
+
+
+class PostgrestTimedOut(Exception):
+    "Connecting to PostgREST endpoint timed out."
+
+
+class PostgrestSession(requests_unixsocket.Session):
+    "HTTP client session directed at a PostgREST endpoint."
+
+    def __init__(self, baseurl, *args, **kwargs):
+        super(PostgrestSession, self).__init__(*args, **kwargs)
+        self.baseurl = baseurl
+
+    def request(self, method, url, *args, **kwargs):
+        # Not using urllib.parse.urljoin to compose the url, as it doesn't play
+        # well with our 'http+unix://' unix domain socket urls.
+        fullurl = self.baseurl + url
+        return super(PostgrestSession, self).request(method, fullurl, *args, **kwargs)
+
+
+@dataclasses.dataclass
+class PostgrestProcess:
+    "Running PostgREST process and its corresponding main and admin endpoints."
+    admin: object
+    process: object
+    session: object
+
+
+@contextlib.contextmanager
+def run(
+    configpath=None,
+    stdin=None,
+    env=None,
+    port=None,
+    host=None,
+    no_pool_connection_available=False,
+):
+    "Run PostgREST and yield an endpoint that is ready for connections."
+
+    with tempfile.TemporaryDirectory() as tmpdir:
+        if port:
+            env["PGRST_SERVER_PORT"] = str(port)
+            env["PGRST_SERVER_HOST"] = host or "localhost"
+            baseurl = f"http://localhost:{port}"
+        else:
+            socketfile = pathlib.Path(tmpdir) / "postgrest.sock"
+            env["PGRST_SERVER_UNIX_SOCKET"] = str(socketfile)
+            baseurl = "http+unix://" + urllib.parse.quote_plus(str(socketfile))
+
+        adminport = freeport()
+        env["PGRST_ADMIN_SERVER_PORT"] = str(adminport)
+        adminurl = f"http://localhost:{adminport}"
+
+        command = [POSTGREST_BIN]
+        env["HPCTIXFILE"] = hpctixfile()
+
+        if configpath:
+            command.append(configpath)
+
+        process = subprocess.Popen(
+            command,
+            stdin=subprocess.PIPE,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.STDOUT,
+            env=env,
+        )
+
+        os.set_blocking(process.stdout.fileno(), False)
+
+        try:
+            process.stdin.write(stdin or b"")
+            process.stdin.close()
+
+            wait_until_ready(adminurl + "/ready")
+
+            process.stdout.read()
+
+            yield PostgrestProcess(
+                process=process,
+                session=PostgrestSession(baseurl),
+                admin=PostgrestSession(adminurl),
+            )
+        finally:
+            if no_pool_connection_available:
+                sleep_pool_connection(baseurl, 10)
+
+            remaining_output = process.stdout.read()
+            if remaining_output:
+                print(remaining_output.decode())
+            process.terminate()
+            try:
+                process.wait(timeout=1)
+            except:
+                process.kill()
+                process.wait()
+
+
+@pytest.fixture(scope="module")
+def metapostgrest():
+    "A shared postgrest instance to use for interacting with the database independently of the instance under test"
+    role = "meta_authenticator"
+    env = {
+        "PGDATABASE": os.environ["PGDATABASE"],
+        "PGHOST": os.environ["PGHOST"],
+        "PGUSER": role,
+        "PGRST_DB_ANON_ROLE": role,
+        "PGRST_DB_CONFIG": "true",
+        "PGRST_LOG_LEVEL": "info",
+        "PGRST_DB_POOL": "1",
+    }
+    with run(env=env) as postgrest:
+        yield postgrest
+
+
+def freeport():
+    "Find a free port on localhost."
+    with contextlib.closing(socket.socket(socket.AF_INET, socket.SOCK_STREAM)) as s:
+        s.bind(("", 0))
+        s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+        return s.getsockname()[1]
+
+
+def wait_until_ready(url):
+    "Wait for the given HTTP endpoint to return a status of 200."
+    session = requests_unixsocket.Session()
+
+    response = None
+    for _ in range(10):
+        try:
+            response = session.get(url, timeout=1)
+            if response.status_code == 200:
+                return
+        except (requests.ConnectionError, requests.ReadTimeout):
+            pass
+
+        time.sleep(0.1)
+
+    if response:
+        raise PostgrestTimedOut(f"{response.status_code}: {response.text}")
+    else:
+        raise PostgrestTimedOut()
+
+
+def sleep_pool_connection(url, seconds):
+    "Sleep a pool connection by calling an RPC that uses pg_sleep"
+    session = requests_unixsocket.Session()
+
+    # The try/except is a hack for not waiting for the response,
+    # taken from https://stackoverflow.com/a/45601591/4692662
+    try:
+        session.get(url + f"/rpc/sleep?seconds={seconds}", timeout=0.1)
+    except requests.exceptions.ReadTimeout:
+        pass
diff --git a/test/io/test_cli.py b/test/io/test_cli.py
new file mode 100644
index 000000000..ae8130f4b
--- /dev/null
+++ b/test/io/test_cli.py
@@ -0,0 +1,227 @@
+"Unit tests for Input/Ouput of PostgREST seen as a black box."
+
+import contextlib
+import dataclasses
+from datetime import datetime
+from itertools import repeat
+from operator import attrgetter
+import os
+import pathlib
+import re
+import shutil
+import signal
+import socket
+import subprocess
+import tempfile
+import threading
+import time
+import urllib.parse
+
+import jwt
+import pytest
+import requests
+import requests_unixsocket
+import yaml
+
+from config import *
+
+
+def itemgetter(*items):
+    "operator.itemgetter with None as fallback when key does not exist"
+    if len(items) == 1:
+        item = items[0]
+
+        def g(obj):
+            return obj.get(item)
+
+    else:
+
+        def g(obj):
+            return tuple(obj.get(item) for item in items)
+
+    return g
+
+
+class PostgrestError(Exception):
+    "Postgrest exited with a non-zero return code."
+
+
+def cli(args, env=None, stdin=None):
+    "Run PostgREST and return stdout."
+    env = env or {}
+
+    command = [POSTGREST_BIN] + args
+    env["HPCTIXFILE"] = hpctixfile()
+
+    process = subprocess.Popen(
+        command, env=env, stdin=subprocess.PIPE, stdout=subprocess.PIPE
+    )
+
+    process.stdin.write(stdin or b"")
+    try:
+        result = process.communicate(timeout=5)[0]
+        if process.returncode != 0:
+            raise PostgrestError()
+        return result.decode()
+    finally:
+        process.kill()
+        process.wait()
+
+
+def dumpconfig(configpath=None, env=None, stdin=None):
+    "Dump the config as parsed by PostgREST."
+    args = ["--dump-config"]
+
+    if configpath:
+        args.append(configpath)
+
+    return cli(args, env=env, stdin=stdin)
+
+
+@pytest.mark.parametrize(
+    "args,env,use_defaultenv,expect",
+    map(itemgetter("args", "env", "use_defaultenv", "expect"), FIXTURES["cli"]),
+    ids=map(itemgetter("name"), FIXTURES["cli"]),
+)
+def test_cli(args, env, use_defaultenv, expect, defaultenv):
+    """
+    When PostgREST is run with <args> arguments and <env>/<defaultenv> environment variabales
+    it should return. Exit code should be according to <expect_error>.
+    """
+    # use --dump-config by default to make sure that the postgrest process will terminate for sure
+    args = args or ["--dump-config"]
+
+    env = env or {}
+    if use_defaultenv:
+        env = {**defaultenv, **env}
+
+    if expect == "error":
+        with pytest.raises(PostgrestError):
+            print(cli(args, env=env))
+    else:
+        dump = cli(args, env=env).split("\n")
+        if expect:
+            assert expect in dump
+
+
+@pytest.mark.parametrize(
+    "expectedconfig",
+    [
+        expectedconfig
+        for expectedconfig in (CONFIGSDIR / "expected").iterdir()
+        if (CONFIGSDIR / expectedconfig.name).exists()
+    ],
+    ids=attrgetter("name"),
+)
+def test_expected_config(expectedconfig):
+    """
+    Configs as dumped by PostgREST should match an expected output.
+
+    Used to test default values, config aliases and environment variables. The
+    expected output for each file in 'configs', if available, is found in the
+    'configs/expected' directory.
+
+    """
+    expected = expectedconfig.read_text()
+    config = CONFIGSDIR / expectedconfig.name
+
+    assert dumpconfig(config) == expected
+
+
+def test_expected_config_from_environment():
+    "Config should be read directly from environment without config file."
+
+    envfile = (CONFIGSDIR / "no-defaults-env.yaml").read_text()
+    env = {k: str(v) for k, v in yaml.load(envfile, Loader=yaml.Loader).items()}
+
+    expected = (CONFIGSDIR / "expected" / "no-defaults.config").read_text()
+    assert dumpconfig(env=env) == expected
+
+
+@pytest.mark.parametrize(
+    "role, expectedconfig",
+    [
+        ("db_config_authenticator", "no-defaults-with-db.config"),
+        ("other_authenticator", "no-defaults-with-db-other-authenticator.config"),
+    ],
+)
+def test_expected_config_from_db_settings(baseenv, role, expectedconfig):
+    "Config should be overriden from database settings"
+
+    config = CONFIGSDIR / "no-defaults.config"
+
+    env = {
+        **baseenv,
+        "PGUSER": role,
+        "PGRST_DB_URI": "postgresql://",
+        "PGRST_DB_CONFIG": "true",
+    }
+
+    expected = (CONFIGSDIR / "expected" / expectedconfig).read_text()
+    assert dumpconfig(configpath=config, env=env) == expected
+
+
+@pytest.mark.parametrize(
+    "config",
+    [conf for conf in CONFIGSDIR.iterdir() if conf.suffix == ".config"],
+    ids=attrgetter("name"),
+)
+def test_stable_config(tmp_path, config, defaultenv):
+    """
+    A dumped, re-read and re-dumped config should match the dumped config.
+
+    Note: only dump vs. re-dump must be equal, as the original config file might
+    be different because of default values, whitespace, and quoting.
+
+    """
+
+    # Set environment variables that some of the configs expect. Using a
+    # complex ROLE_CLAIM_KEY to make sure quoting works.
+    env = {
+        **defaultenv,
+        "ROLE_CLAIM_KEY": '."https://www.example.com/roles"[0].value',
+        "POSTGREST_TEST_SOCKET": "/tmp/postgrest.sock",
+        "POSTGREST_TEST_PORT": "80",
+        "JWT_SECRET_FILE": "a_file",
+    }
+
+    # Some configs expect input from stdin, at least on base64.
+    stdin = b"Y29ubmVjdGlvbl9zdHJpbmc="
+
+    dumped = dumpconfig(config, env=env, stdin=stdin)
+
+    tmpconfigpath = tmp_path / "config"
+    tmpconfigpath.write_text(dumped)
+    redumped = dumpconfig(tmpconfigpath, env=env)
+
+    assert dumped == redumped
+
+
+@pytest.mark.parametrize("invalidroleclaimkey", FIXTURES["invalidroleclaimkeys"])
+def test_invalid_role_claim_key(invalidroleclaimkey, defaultenv):
+    "Given an invalid role-claim-key, Postgrest should exit with a non-zero exit code."
+    env = {
+        **defaultenv,
+        "PGRST_JWT_ROLE_CLAIM_KEY": invalidroleclaimkey,
+    }
+
+    with pytest.raises(PostgrestError):
+        dump = dumpconfig(env=env)
+        for line in dump.split("\n"):
+            if line.startswith("jwt-role-claim-key"):
+                print(line)
+
+
+@pytest.mark.parametrize("invalidopenapimodes", FIXTURES["invalidopenapimodes"])
+def test_invalid_openapi_mode(invalidopenapimodes, defaultenv):
+    "Given an invalid openapi-mode, Postgrest should exit with a non-zero exit code."
+    env = {
+        **defaultenv,
+        "PGRST_OPENAPI_MODE": invalidopenapimodes,
+    }
+
+    with pytest.raises(PostgrestError):
+        dump = dumpconfig(CONFIGSDIR / "defaults.config", env=env)
+        for line in dump.split("\n"):
+            if line.startswith("openapi-mode"):
+                print(line)
diff --git a/test/io/test_io.py b/test/io/test_io.py
index 07bd6bb0f..9b551b693 100644
--- a/test/io/test_io.py
+++ b/test/io/test_io.py
@@ -1,427 +1,18 @@
 "Unit tests for Input/Ouput of PostgREST seen as a black box."
 
-import contextlib
-import dataclasses
 from datetime import datetime
-from itertools import repeat
 from operator import attrgetter
 import os
-import pathlib
 import re
-import shutil
 import signal
 import socket
-import subprocess
-import tempfile
-import threading
 import time
-import urllib.parse
 
-import jwt
 import pytest
-import requests
-import requests_unixsocket
-import yaml
 
-
-BASEDIR = pathlib.Path(os.path.realpath(__file__)).parent
-CONFIGSDIR = BASEDIR / "configs"
-FIXTURES = yaml.load((BASEDIR / "fixtures.yaml").read_text(), Loader=yaml.Loader)
-POSTGREST_BIN = shutil.which("postgrest")
-SECRET = "reallyreallyreallyreallyverysafe"
-
-
-def itemgetter(*items):
-    "operator.itemgetter with None as fallback when key does not exist"
-    if len(items) == 1:
-        item = items[0]
-
-        def g(obj):
-            return obj.get(item)
-
-    else:
-
-        def g(obj):
-            return tuple(obj.get(item) for item in items)
-
-    return g
-
-
-class Thread(threading.Thread):
-    "Variant of threading.Thread that re-raises any exceptions when joining the thread"
-
-    def __init__(self, *args, **kwargs):
-        self._exception = None
-        super(Thread, self).__init__(*args, **kwargs)
-
-    def run(self):
-        try:
-            super(Thread, self).run()
-        except Exception as e:
-            self._exception = e
-
-    def join(self):
-        super(Thread, self).join()
-        if self._exception is not None:
-            raise self._exception
-
-
-class PostgrestTimedOut(Exception):
-    "Connecting to PostgREST endpoint timed out."
-
-
-class PostgrestError(Exception):
-    "Postgrest exited with a non-zero return code."
-
-
-class PostgrestSession(requests_unixsocket.Session):
-    "HTTP client session directed at a PostgREST endpoint."
-
-    def __init__(self, baseurl, *args, **kwargs):
-        super(PostgrestSession, self).__init__(*args, **kwargs)
-        self.baseurl = baseurl
-
-    def request(self, method, url, *args, **kwargs):
-        # Not using urllib.parse.urljoin to compose the url, as it doesn't play
-        # well with our 'http+unix://' unix domain socket urls.
-        fullurl = self.baseurl + url
-        return super(PostgrestSession, self).request(method, fullurl, *args, **kwargs)
-
-
-@dataclasses.dataclass
-class PostgrestProcess:
-    "Running PostgREST process and its corresponding main and admin endpoints."
-    admin: object
-    process: object
-    session: object
-
-
-@pytest.fixture
-def dburi():
-    "Postgres database connection URI."
-    dbname = os.environ["PGDATABASE"]
-    host = os.environ["PGHOST"]
-    user = os.environ["PGUSER"]
-    return f"postgresql://?dbname={dbname}&host={host}&user={user}".encode()
-
-
-@pytest.fixture
-def baseenv():
-    "Base environment to connect to PostgreSQL"
-    return {
-        "PGDATABASE": os.environ["PGDATABASE"],
-        "PGHOST": os.environ["PGHOST"],
-        "PGUSER": os.environ["PGUSER"],
-    }
-
-
-@pytest.fixture
-def defaultenv(baseenv):
-    "Default environment for PostgREST."
-    return {
-        **baseenv,
-        "PGRST_DB_CONFIG": "true",
-        "PGRST_LOG_LEVEL": "info",
-        "PGRST_DB_POOL": "1",
-    }
-
-
-@pytest.fixture(scope="module")
-def metapostgrest():
-    "A shared postgrest instance to use for interacting with the database independently of the instance under test"
-    role = "meta_authenticator"
-    env = {
-        "PGDATABASE": os.environ["PGDATABASE"],
-        "PGHOST": os.environ["PGHOST"],
-        "PGUSER": role,
-        "PGRST_DB_ANON_ROLE": role,
-        "PGRST_DB_CONFIG": "true",
-        "PGRST_LOG_LEVEL": "info",
-        "PGRST_DB_POOL": "1",
-    }
-    with run(env=env) as postgrest:
-        yield postgrest
-
-
-def hpctixfile():
-    "Returns an individual filename for each test, if the HPCTIXFILE environment variable is set."
-    if "HPCTIXFILE" not in os.environ:
-        return ""
-
-    tixfile = pathlib.Path(os.environ["HPCTIXFILE"])
-    test = hash(os.environ["PYTEST_CURRENT_TEST"])
-    return tixfile.with_suffix(f".{test}.tix")
-
-
-def cli(args, env=None, stdin=None):
-    "Run PostgREST and return stdout."
-    env = env or {}
-
-    command = [POSTGREST_BIN] + args
-    env["HPCTIXFILE"] = hpctixfile()
-
-    process = subprocess.Popen(
-        command, env=env, stdin=subprocess.PIPE, stdout=subprocess.PIPE
-    )
-
-    process.stdin.write(stdin or b"")
-    try:
-        result = process.communicate(timeout=5)[0]
-        if process.returncode != 0:
-            raise PostgrestError()
-        return result.decode()
-    finally:
-        process.kill()
-        process.wait()
-
-
-def dumpconfig(configpath=None, env=None, stdin=None):
-    "Dump the config as parsed by PostgREST."
-    args = ["--dump-config"]
-
-    if configpath:
-        args.append(configpath)
-
-    return cli(args, env=env, stdin=stdin)
-
-
-@contextlib.contextmanager
-def run(
-    configpath=None,
-    stdin=None,
-    env=None,
-    port=None,
-    host=None,
-    no_pool_connection_available=False,
-):
-    "Run PostgREST and yield an endpoint that is ready for connections."
-
-    with tempfile.TemporaryDirectory() as tmpdir:
-        if port:
-            env["PGRST_SERVER_PORT"] = str(port)
-            env["PGRST_SERVER_HOST"] = host or "localhost"
-            baseurl = f"http://localhost:{port}"
-        else:
-            socketfile = pathlib.Path(tmpdir) / "postgrest.sock"
-            env["PGRST_SERVER_UNIX_SOCKET"] = str(socketfile)
-            baseurl = "http+unix://" + urllib.parse.quote_plus(str(socketfile))
-
-        adminport = freeport()
-        env["PGRST_ADMIN_SERVER_PORT"] = str(adminport)
-        adminurl = f"http://localhost:{adminport}"
-
-        command = [POSTGREST_BIN]
-        env["HPCTIXFILE"] = hpctixfile()
-
-        if configpath:
-            command.append(configpath)
-
-        process = subprocess.Popen(
-            command,
-            stdin=subprocess.PIPE,
-            stdout=subprocess.PIPE,
-            stderr=subprocess.STDOUT,
-            env=env,
-        )
-
-        os.set_blocking(process.stdout.fileno(), False)
-
-        try:
-            process.stdin.write(stdin or b"")
-            process.stdin.close()
-
-            wait_until_ready(adminurl + "/ready")
-
-            process.stdout.read()
-
-            yield PostgrestProcess(
-                process=process,
-                session=PostgrestSession(baseurl),
-                admin=PostgrestSession(adminurl),
-            )
-        finally:
-            if no_pool_connection_available:
-                sleep_pool_connection(baseurl, 10)
-
-            remaining_output = process.stdout.read()
-            if remaining_output:
-                print(remaining_output.decode())
-            process.terminate()
-            try:
-                process.wait(timeout=1)
-            except:
-                process.kill()
-                process.wait()
-
-
-def freeport():
-    "Find a free port on localhost."
-    with contextlib.closing(socket.socket(socket.AF_INET, socket.SOCK_STREAM)) as s:
-        s.bind(("", 0))
-        s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-        return s.getsockname()[1]
-
-
-def wait_until_ready(url):
-    "Wait for the given HTTP endpoint to return a status of 200."
-    session = requests_unixsocket.Session()
-
-    response = None
-    for _ in range(10):
-        try:
-            response = session.get(url, timeout=1)
-            if response.status_code == 200:
-                return
-        except (requests.ConnectionError, requests.ReadTimeout):
-            pass
-
-        time.sleep(0.1)
-
-    if response:
-        raise PostgrestTimedOut(f"{response.status_code}: {response.text}")
-    else:
-        raise PostgrestTimedOut()
-
-
-def sleep_pool_connection(url, seconds):
-    "Sleep a pool connection by calling an RPC that uses pg_sleep"
-    session = requests_unixsocket.Session()
-
-    # The try/except is a hack for not waiting for the response,
-    # taken from https://stackoverflow.com/a/45601591/4692662
-    try:
-        session.get(url + f"/rpc/sleep?seconds={seconds}", timeout=0.1)
-    except requests.exceptions.ReadTimeout:
-        pass
-
-
-def authheader(token):
-    "Bearer token HTTP authorization header."
-    return {"Authorization": f"Bearer {token}"}
-
-
-def jwtauthheader(claim, secret):
-    "Authorization header with signed JWT."
-    return authheader(jwt.encode(claim, secret))
-
-
-@pytest.mark.parametrize(
-    "args,env,use_defaultenv,expect",
-    map(itemgetter("args", "env", "use_defaultenv", "expect"), FIXTURES["cli"]),
-    ids=map(itemgetter("name"), FIXTURES["cli"]),
-)
-def test_cli(args, env, use_defaultenv, expect, defaultenv):
-    """
-    When PostgREST is run with <args> arguments and <env>/<defaultenv> environment variabales
-    it should return. Exit code should be according to <expect_error>.
-    """
-    # use --dump-config by default to make sure that the postgrest process will terminate for sure
-    args = args or ["--dump-config"]
-
-    env = env or {}
-    if use_defaultenv:
-        env = {**defaultenv, **env}
-
-    if expect == "error":
-        with pytest.raises(PostgrestError):
-            print(cli(args, env=env))
-    else:
-        dump = cli(args, env=env).split("\n")
-        if expect:
-            assert expect in dump
-
-
-@pytest.mark.parametrize(
-    "expectedconfig",
-    [
-        expectedconfig
-        for expectedconfig in (CONFIGSDIR / "expected").iterdir()
-        if (CONFIGSDIR / expectedconfig.name).exists()
-    ],
-    ids=attrgetter("name"),
-)
-def test_expected_config(expectedconfig):
-    """
-    Configs as dumped by PostgREST should match an expected output.
-
-    Used to test default values, config aliases and environment variables. The
-    expected output for each file in 'configs', if available, is found in the
-    'configs/expected' directory.
-
-    """
-    expected = expectedconfig.read_text()
-    config = CONFIGSDIR / expectedconfig.name
-
-    assert dumpconfig(config) == expected
-
-
-def test_expected_config_from_environment():
-    "Config should be read directly from environment without config file."
-
-    envfile = (CONFIGSDIR / "no-defaults-env.yaml").read_text()
-    env = {k: str(v) for k, v in yaml.load(envfile, Loader=yaml.Loader).items()}
-
-    expected = (CONFIGSDIR / "expected" / "no-defaults.config").read_text()
-    assert dumpconfig(env=env) == expected
-
-
-@pytest.mark.parametrize(
-    "role, expectedconfig",
-    [
-        ("db_config_authenticator", "no-defaults-with-db.config"),
-        ("other_authenticator", "no-defaults-with-db-other-authenticator.config"),
-    ],
-)
-def test_expected_config_from_db_settings(baseenv, role, expectedconfig):
-    "Config should be overriden from database settings"
-
-    config = CONFIGSDIR / "no-defaults.config"
-
-    env = {
-        **baseenv,
-        "PGUSER": role,
-        "PGRST_DB_URI": "postgresql://",
-        "PGRST_DB_CONFIG": "true",
-    }
-
-    expected = (CONFIGSDIR / "expected" / expectedconfig).read_text()
-    assert dumpconfig(configpath=config, env=env) == expected
-
-
-@pytest.mark.parametrize(
-    "config",
-    [conf for conf in CONFIGSDIR.iterdir() if conf.suffix == ".config"],
-    ids=attrgetter("name"),
-)
-def test_stable_config(tmp_path, config, defaultenv):
-    """
-    A dumped, re-read and re-dumped config should match the dumped config.
-
-    Note: only dump vs. re-dump must be equal, as the original config file might
-    be different because of default values, whitespace, and quoting.
-
-    """
-
-    # Set environment variables that some of the configs expect. Using a
-    # complex ROLE_CLAIM_KEY to make sure quoting works.
-    env = {
-        **defaultenv,
-        "ROLE_CLAIM_KEY": '."https://www.example.com/roles"[0].value',
-        "POSTGREST_TEST_SOCKET": "/tmp/postgrest.sock",
-        "POSTGREST_TEST_PORT": "80",
-        "JWT_SECRET_FILE": "a_file",
-    }
-
-    # Some configs expect input from stdin, at least on base64.
-    stdin = b"Y29ubmVjdGlvbl9zdHJpbmc="
-
-    dumped = dumpconfig(config, env=env, stdin=stdin)
-
-    tmpconfigpath = tmp_path / "config"
-    tmpconfigpath.write_text(dumped)
-    redumped = dumpconfig(tmpconfigpath, env=env)
-
-    assert dumped == redumped
+from config import *
+from util import *
+from postgrest import *
 
 
 def test_port_connection(defaultenv):
@@ -536,36 +127,6 @@ def test_role_claim_key(roleclaim, defaultenv):
         assert response.status_code == roleclaim["expected_status"]
 
 
-@pytest.mark.parametrize("invalidroleclaimkey", FIXTURES["invalidroleclaimkeys"])
-def test_invalid_role_claim_key(invalidroleclaimkey, defaultenv):
-    "Given an invalid role-claim-key, Postgrest should exit with a non-zero exit code."
-    env = {
-        **defaultenv,
-        "PGRST_JWT_ROLE_CLAIM_KEY": invalidroleclaimkey,
-    }
-
-    with pytest.raises(PostgrestError):
-        dump = dumpconfig(env=env)
-        for line in dump.split("\n"):
-            if line.startswith("jwt-role-claim-key"):
-                print(line)
-
-
-@pytest.mark.parametrize("invalidopenapimodes", FIXTURES["invalidopenapimodes"])
-def test_invalid_openapi_mode(invalidopenapimodes, defaultenv):
-    "Given an invalid openapi-mode, Postgrest should exit with a non-zero exit code."
-    env = {
-        **defaultenv,
-        "PGRST_OPENAPI_MODE": invalidopenapimodes,
-    }
-
-    with pytest.raises(PostgrestError):
-        dump = dumpconfig(CONFIGSDIR / "defaults.config", env=env)
-        for line in dump.split("\n"):
-            if line.startswith("openapi-mode"):
-                print(line)
-
-
 def test_iat_claim(defaultenv):
     """
     A claim with an 'iat' (issued at) attribute should be successful.
diff --git a/test/io/util.py b/test/io/util.py
new file mode 100644
index 000000000..7d677c086
--- /dev/null
+++ b/test/io/util.py
@@ -0,0 +1,42 @@
+import contextlib
+import socket
+import threading
+
+import jwt
+
+
+class Thread(threading.Thread):
+    "Variant of threading.Thread that re-raises any exceptions when joining the thread"
+
+    def __init__(self, *args, **kwargs):
+        self._exception = None
+        super(Thread, self).__init__(*args, **kwargs)
+
+    def run(self):
+        try:
+            super(Thread, self).run()
+        except Exception as e:
+            self._exception = e
+
+    def join(self):
+        super(Thread, self).join()
+        if self._exception is not None:
+            raise self._exception
+
+
+def freeport():
+    "Find a free port on localhost."
+    with contextlib.closing(socket.socket(socket.AF_INET, socket.SOCK_STREAM)) as s:
+        s.bind(("", 0))
+        s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+        return s.getsockname()[1]
+
+
+def authheader(token):
+    "Bearer token HTTP authorization header."
+    return {"Authorization": f"Bearer {token}"}
+
+
+def jwtauthheader(claim, secret):
+    "Authorization header with signed JWT."
+    return authheader(jwt.encode(claim, secret))