Reorganize tests (#10)

Create new test scenarios and adapt scenarios of load balancing to be
parametrized, given that the tests were the same for the round robin and
least connections configuration.

Also add markers on every test case so that it's possible to run tests
for a specific feature without running every test.

README.md

@@ -8,9 +8,6 @@ load balancer.
 - Enhance HTTP parsing implementation, parse headers over 4kB, support
   chunked transfer, support all methods.
 - Enhance error handling making sure the server won't crash.
-- Write better tests cases, the ones written right now(can be found at
-  `tests` directory) only check basic things and there are only a few
-  crash scenarios.
 
 ## Features
 

pytest.ini

@@ -0,0 +1,5 @@
+[pytest]
+markers =
+    command: Test for the command server.
+    round_robin: Test ekilibri with the round robin configuration.
+    least_connections: Test ekilibri with the least connections configuration.

src/bin/server.rs

@@ -91,6 +91,10 @@ async fn main() {
 
     let config = Arc::new(config);
 
+    if config.pool_size == 0 {
+        panic!("Pool size has to be greater than zero.")
+    }
+
     let connections_counters = Arc::new(RwLock::new(Vec::with_capacity(config.servers.len())));
     for _ in &config.servers {
         connections_counters.write().await.push(AtomicU64::new(0));

tests/command_server_test.py

@@ -1,8 +1,10 @@
+import pytest
 import requests
 
 URL = "http://localhost:8081"
 
 
+@pytest.mark.command
 def test_echo_server():
     payload = "test parsing this info"
 
@@ -16,6 +18,7 @@ def test_echo_server():
     assert response.text == payload
 
 
+@pytest.mark.command
 def test_echo_server_with_content_type():
     payload = """{"key": "value"}"""
 
@@ -29,6 +32,7 @@ def test_echo_server_with_content_type():
     assert response.text == payload
 
 
+@pytest.mark.command
 def test_echo_server_with_big_body():
     payload = "test parsing this info" * 1000
 
@@ -42,6 +46,7 @@ def test_echo_server_with_big_body():
     assert response.text == payload
 
 
+@pytest.mark.command
 def test_echo_server_with_huge_body():
     payload = "test parsing this info" * 10000
 
@@ -55,12 +60,14 @@ def test_echo_server_with_huge_body():
     assert response.text == payload
 
 
+@pytest.mark.command
 def test_get_not_found():
     response = requests.get(URL + "/not-found")
     assert response.status_code == 404
     assert response.text == ""
 
 
+@pytest.mark.command
 def test_post_not_found():
     response = requests.post(URL + "/not-found", data="data")
     assert response.status_code == 404

tests/common.py

@@ -0,0 +1,25 @@
+from time import sleep
+from typing import Set
+
+import requests
+
+EKILIBRI_URL = "http://localhost:8080"
+
+
+def assert_health(n: int, status: int):
+    for _ in range(n):
+        response = requests.get(EKILIBRI_URL + "/health")
+        assert response.status_code == status
+
+
+def assert_health_multiple_status(n: int, statuses: Set[int]):
+    """Checks the response for the health endpoint validating the status code
+    could be of different values."""
+    for _ in range(n):
+        response = requests.get(EKILIBRI_URL + "/health")
+        assert response.status_code in statuses
+
+
+def wait_fail_window():
+    """Waits the fail window for ekilibri to remove the server from the healthy servers list."""
+    sleep(5)

tests/ekilibri-least-connections-timeout.toml

@@ -0,0 +1,13 @@
+servers = [
+    "127.0.0.1:8081",
+    "127.0.0.1:8082",
+    "127.0.0.1:8083"
+]
+strategy = "LeastConnections"
+max_fails = 1
+fail_window = 5
+connection_timeout = 1000
+write_timeout = 1000
+read_timeout = 1000
+health_check_path = "/sleep"
+pool_size = 10

tests/ekilibri-least-connections.toml

@@ -5,7 +5,7 @@ servers = [
 ]
 strategy = "LeastConnections"
 max_fails = 1
-fail_window = 10
+fail_window = 5
 connection_timeout = 1000
 write_timeout = 1000
 read_timeout = 1000

tests/ekilibri-round-robin-timeout.toml

@@ -4,8 +4,8 @@ servers = [
     "127.0.0.1:8083"
 ]
 strategy = "RoundRobin"
-max_fails = 5
-fail_window = 60
+max_fails = 1
+fail_window = 5
 connection_timeout = 1000
 write_timeout = 1000
 read_timeout = 1000

tests/ekilibri-round-robin.toml

@@ -5,7 +5,7 @@ servers = [
 ]
 strategy = "RoundRobin"
 max_fails = 1
-fail_window = 10
+fail_window = 5
 connection_timeout = 1000
 write_timeout = 1000
 read_timeout = 1000

tests/ekilibri_setup.py

@@ -30,7 +30,7 @@ def initialize_command_server(
 def kill_process(pid):
     if pid != -1:
         os.kill(pid, signal.SIGTERM)
-        time.sleep(0.5)
+        time.sleep(0.1)
 
 
 def setup_ekilibri_server(request, config_path: str) -> int:

tests/get_ekilibri_test.py

@@ -0,0 +1,54 @@
+import pytest
+import requests
+
+from common import EKILIBRI_URL, assert_health
+from ekilibri_setup import kill_process, setup_ekilibri_server
+
+
+@pytest.mark.parametrize(
+    "configuration",
+    [
+        pytest.param("least-connections", marks=pytest.mark.least_connections),
+        pytest.param("round-robin", marks=pytest.mark.round_robin),
+    ],
+)
+def test_multiple_get_request_to_three_servers(request, configuration):
+    pid = setup_ekilibri_server(request, f"tests/ekilibri-{configuration}.toml")
+    try:
+        assert_health(100, status=200)
+    finally:
+        kill_process(pid)
+
+
+@pytest.mark.parametrize(
+    "configuration",
+    [
+        pytest.param("least-connections", marks=pytest.mark.least_connections),
+        pytest.param("round-robin", marks=pytest.mark.round_robin),
+    ],
+)
+def test_multiple_get_request_with_timeout(request, configuration):
+    pid = setup_ekilibri_server(request, f"tests/ekilibri-{configuration}.toml")
+    try:
+        for _ in range(10):
+            response = requests.get(EKILIBRI_URL + "/sleep")
+            assert response.status_code == 504
+    finally:
+        kill_process(pid)
+
+
+@pytest.mark.parametrize(
+    "configuration",
+    [
+        pytest.param("least-connections", marks=pytest.mark.least_connections),
+        pytest.param("round-robin", marks=pytest.mark.round_robin),
+    ],
+)
+def test_get_not_found(request, configuration):
+    pid = setup_ekilibri_server(request, f"tests/ekilibri-{configuration}.toml")
+    try:
+        response = requests.get(EKILIBRI_URL + "/not-found")
+        assert response.status_code == 404
+        assert response.text == ""
+    finally:
+        kill_process(pid)

tests/health_check_test.py

@@ -0,0 +1,25 @@
+import pytest
+
+from common import assert_health, wait_fail_window
+from ekilibri_setup import kill_process, setup_ekilibri_server
+
+
+@pytest.mark.parametrize(
+    "configuration",
+    [
+        pytest.param("least-connections", marks=pytest.mark.least_connections),
+        pytest.param("round-robin", marks=pytest.mark.round_robin),
+    ],
+)
+def test_get_requests_when_the_health_check_path_is_timing_out(request, configuration):
+    pid = setup_ekilibri_server(request, f"tests/ekilibri-{configuration}-timeout.toml")
+    try:
+        # First requests should be ok, given that Ekilibri still hasn't removed
+        # the servers from healthy servers list.
+        assert_health(100, status=200)
+
+        wait_fail_window()
+
+        assert_health(10, status=502)
+    finally:
+        kill_process(pid)