Refactor testinfra docker to support parametrize

This accomplishes the same thing as the previous tests, without using testinfra docker's boilerplate example, which had some drawbacks: Adding @parametrize to the previous version didn't allow overriding the pytest.mark docker arg, image:tag, or cmd with a parametrized test containing different expected results associated with either the alpine/debian tag.  Isntead it'd run all the parameters against both tags...e.g. nginx and lighttpd test would run agains both alpine and docker when parametizing on the test level.

test/conftest.py

@@ -1,53 +1,55 @@
 import pytest
 import testinfra
 
-# Use testinfra to get a handy function to run commands locally
-check_output = testinfra.get_backend(
-    "local://"
-).get_module("Command").check_output
+@pytest.fixture()
+def args(request): 
+    return '-e ServerIP="192.168.100.2"'
 
+@pytest.fixture(params=['alpine', 'debian'])
+def tag(request):
+    return request.param
 
-@pytest.fixture
-def TestinfraBackend(request):
-    docker_run = "docker run -d {}".format(request.param)
-    print docker_run
+@pytest.fixture()
+def image(request, tag): 
+    return 'diginc/pi-hole:{}'.format(tag)
 
-    docker_id = check_output(docker_run)
-    check_output("docker exec %s sed -i 's/^gravity_spinup/#donotcurl/g' /usr/local/bin/gravity.sh", docker_id)
+@pytest.fixture()
+def cmd(request): 
+    return '/start.sh'
+
+DEBUG = []
+
+@pytest.fixture()
+def Docker(request, LocalCommand, args, image, cmd):
+    assert 'docker' in LocalCommand.check_output('id'), "Are you in the docker group?"
+    docker_run = "docker run -d {} {} {}".format(args, image, cmd)
+    if 'run' in DEBUG:
+        assert docker_run  == 'docker run -d -e ServerIP="192.168.100.2" diginc/pi-hole:alpine /start.sh'
+    docker_id = LocalCommand.check_output(docker_run)
+    LocalCommand.check_output("docker exec %s sed -i 's/^gravity_spinup/#donotcurl/g' /usr/local/bin/gravity.sh", docker_id)
 
     def teardown():
-        check_output("docker rm -f %s", docker_id)
+        LocalCommand.check_output("docker rm -f %s", docker_id)
     request.addfinalizer(teardown)
 
     return testinfra.get_backend("docker://" + docker_id)
 
-
-def pytest_generate_tests(metafunc):
-    if "TestinfraBackend" in metafunc.fixturenames:
-
-        mark_args = getattr(metafunc.function, "docker_args", None)
-        docker_args = []
-        if mark_args is not None:
-            docker_args = docker_args + list(mark_args.args)
-
-        mark_images = getattr(metafunc.function, "docker_images", None)
-        images = ['diginc/pi-hole:alpine', 'diginc/pi-hole:debian']
-        if mark_images is not None:
-            images = mark_images.args
-
-        mark_cmd = getattr(metafunc.function, "docker_cmd", None)
-        command = 'tail -f /dev/null'
-        if mark_cmd is not None:
-            command = " ".join(mark_cmd.args)
-
-        docker_run_args = []
-        for img in images:
-            docker_run_args.append('{} {} {}'.format(" ".join(docker_args),
-                                                  img, command))
-        if getattr(metafunc.function, "persistent", None) is not None:
-            scope = "session"
-        else:
-            scope = "function"
-
-        metafunc.parametrize(
-            "TestinfraBackend", docker_run_args, indirect=True, scope=scope)
+@pytest.fixture
+def Slow():
+    """
+    Run a slow check, check if the state is correct for `timeout` seconds.
+    """
+    import time
+    def slow(check, timeout=30):
+        timeout_at = time.time() + timeout
+        while True:
+            try:
+                assert check()
+            except AssertionError, e:
+                if timeout_at < time.time():
+                    time.sleep(1)
+                else:
+                    raise e
+            else:
+                return
+    return slow

test/test_start.py

@@ -1,12 +1,32 @@
 import pytest
+''' conftest.py provides the defaults through fixtures '''
+''' Note, testinfra builtins don't seem fully compatible with 
+        docker containers (esp. alpine) stripped down nature '''
 
-def test_ServerIP_missing_env_triggers_error(Command):
-    start = Command.run('/start.sh')
+def test_pihole_default_run_command(Docker):
+    expected_proc = '/sbin/tini -- /start.sh'
+    pgrep = 'pgrep -f "{}" | wc -l || echo 0'.format(expected_proc)
+    find_proc = Docker.run(pgrep).stdout
+    if int(find_proc) < 1:
+        print Docker.run('ps -ef')
+        print "{} : {}".format(pgrep, find_proc)
+        assert False, '{}: Couldn\'t find proc {}'.format(tag, expected_proc)
+
+@pytest.mark.parametrize('args', [ '' ])
+@pytest.mark.parametrize('cmd', [ 'tail -f /dev/null' ])
+def test_ServerIP_missing_triggers_start_error(Docker):
+    ''' When args to docker are empty start.sh exits saying ServerIP is required '''
+    start = Docker.run('/start.sh')
     error_msg = "ERROR: To function correctly you must pass an environment variables of 'ServerIP' into the docker container"
     assert start.rc == 1
     assert error_msg in start.stdout
 
-@pytest.mark.docker_args('-e ServerIP="192.168.1.2"')
-@pytest.mark.docker_cmd('/start.sh')
-def test_ServerIP_allows_normal_startup(Command):
-    assert Command.run('pgrep -f /start.sh | wc') != 0
+@pytest.mark.parametrize('tag,webserver', [
+    ( 'alpine', 'nginx' ),
+    ( 'debian', 'lighttpd' )
+])
+def test_start_launches_dns_and_a_webserver(Docker, webserver, Slow):
+    ''' after we wait for start to finish '''
+    import time
+    Socket = Docker.get_module("Socket")
+    Slow(lambda: Docker.run( 'ps -ef | grep -q "{}"'.format(webserver) ).rc == 0)