Introduce a test for the development server. Fix #3718.

getnikola · Jan 1, 2024 · 66d8a5a · 66d8a5a
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diff --git a/tests/data/dev_server_sample_output_folder/index.html b/tests/data/dev_server_sample_output_folder/index.html
@@ -0,0 +1,9 @@
+<html>
+    <head>
+        <title>Dev server test fixture</title>
+    </head>
+    <body>
+        <h1>This is a dummy file for the dev server to serve</h1>
+        <p>...during the tests ✔.</p>
+    </body>
+</html>
diff --git a/tests/integration/test_dev_server.py b/tests/integration/test_dev_server.py
@@ -0,0 +1,156 @@
+import asyncio
+import nikola.plugins.command.auto as auto
+from nikola.utils import get_logger
+import pytest
+import pathlib
+import socket
+from typing import Optional
+import urllib.request
+
+from ..helper import FakeSite
+
+SERVER_ADDRESS = "localhost"
+TEST_MAX_DURATION = 10  # Watchdog: Give up the test if it did not succeed during this time span.
+SERVER_STARTUP_TIME = 0.1  # Max time, in seconds, we expect the server to need to come up.
+
+# Folder that has the fixture file we expect the server to serve:
+OUTPUT_FOLDER = pathlib.Path.cwd() / "tests" / "data" / "dev_server_sample_output_folder"
+
+LOGGER = get_logger("test_dev_server")
+
+
+def find_unused_port() -> int:
+    """Ask the OS for a currently unused port number.
+
+    (More precisely, a port that can be used for a TCP server servicing SERVER_ADDRESS.)
+    We use a method here rather than a fixture to minimize side effects of failing tests.
+    """
+    s = socket.socket()
+    try:
+        ANY_PORT = 0
+        s.bind((SERVER_ADDRESS, ANY_PORT))
+        address, port = s.getsockname()
+        LOGGER.info("Trying to set up dev server on http://%s:%i/", address, port)
+        return port
+    finally:
+        s.close()
+
+
+def test_serves_root_dir(site, expected_text) -> None:
+    command_auto = auto.CommandAuto()
+    command_auto.set_site(site)
+    options = {
+        "browser": False,
+        "ipv6": False,
+        "address": SERVER_ADDRESS,
+        "port": find_unused_port(),
+        "db-file": "/dev/null",
+        "backend": "No backend",
+        "no-server": False
+    }
+
+    # We start an event loop, run the test in an executor,
+    # and wait for the event loop to terminate.
+    # These variables help to transport the test result to
+    # the main thread outside the event loop:
+    test_was_successful = False
+    test_problem_description = "Async test setup apparently broken"
+    test_inner_error: Optional[BaseException] = None
+
+    async def grab_loop_and_run_test() -> None:
+        loop = asyncio.get_running_loop()
+        watchdog_handle = loop.call_later(TEST_MAX_DURATION, lambda: loop.stop())
+        nonlocal test_problem_description
+        test_problem_description = f"Test did not complete within {TEST_MAX_DURATION} seconds."
+
+        def run_test() -> None:
+            nonlocal test_was_successful, test_problem_description, test_inner_error
+            try:
+                server_base_uri = f"http://{options['address']}:{options['port']}/"
+
+                # First subtest: Does the dev server serve the fixture HTML file as expected?
+                with urllib.request.urlopen(server_base_uri) as res:
+                    assert res.status == 200, f"dev server access failed: {res.status} {res.reason}"
+                    content_type = res.getheader("Content-Type")
+                    assert "text/html; charset=utf-8" == content_type
+                    html = str(res.read(), encoding="utf-8")
+                    assert expected_text in html
+
+                # Second subtest: Does the dev server serve something for the livereload JS?
+                with urllib.request.urlopen(f"{server_base_uri}livereload.js?snipver=1") as res_js:
+                    assert res_js.status == 200, \
+                        f"dev server access to livereload failed: {res_js.status} {res_js.reason}"
+                    content_type_js = res_js.getheader("Content-Type")
+                    assert "text/javascript" in content_type_js or \
+                           "application/javascript" in content_type_js  # Seen under Python 3.9, deprecated.
+                    res_js.read()
+
+                test_was_successful = True
+                test_problem_description = "No problem. All is well."
+            except AssertionError as ae:
+                test_inner_error = ae
+            finally:
+                LOGGER.info("Test completed, %s: %s",
+                            "successfully" if test_was_successful else "failing",
+                            test_problem_description)
+                loop.call_soon_threadsafe(lambda: watchdog_handle.cancel())
+
+                # We give the outer grab_loop_and_run_test a chance to complete
+                # before burning the bridge:
+                loop.call_soon_threadsafe(lambda: loop.call_later(0.05, lambda: loop.stop()))
+        await loop.run_in_executor(None, run_test)
+
+    # We defeat the nikola site building functionality, so this does not actually get called.
+    # But the setup code sets this up and needs a command list for that.
+    command_auto.nikola_cmd = ["echo"]
+
+    # Defeat the site building functionality, and instead insert the test:
+    command_auto.run_initial_rebuild = grab_loop_and_run_test
+
+    # Start the development server
+    # which under the hood runs our test when trying to build the site:
+    command_auto.execute(options=options)
+
+    # Verify the test succeeded:
+    if test_inner_error is not None:
+        raise test_inner_error
+    assert test_was_successful, test_problem_description
+
+
+class MyFakeSite(FakeSite):
+    def __init__(self, config, configuration_filename):
+        self.configured = True
+        self.debug = True
+        self.THEMES = []
+        self._plugin_places = []
+        self.registered_auto_watched_folders = set()
+        self.config = config
+        self.configuration_filename = configuration_filename
+
+
+@pytest.fixture(scope="module")
+def site() -> MyFakeSite:
+    assert OUTPUT_FOLDER.is_dir(), \
+        f"Could not find dev server test fixture {OUTPUT_FOLDER.as_posix()}"
+
+    config = {
+        "post_pages": [],
+        "FILES_FOLDERS": [],
+        "GALLERY_FOLDERS": [],
+        "LISTINGS_FOLDERS": [],
+        "IMAGE_FOLDERS": [],
+        "OUTPUT_FOLDER": OUTPUT_FOLDER.as_posix(),
+    }
+    return MyFakeSite(config, "conf.py")
+
+
+@pytest.fixture(scope="module")
+def expected_text():
+    """Read the index.html file from the fixture folder and return most of it.
+
+    For life reload, the server will fiddle with HTML <head>,
+    so this only returns everything after the opening <body> tag.
+    """
+    with open(OUTPUT_FOLDER / "index.html") as html_file:
+        all_html = html_file.read()
+        return all_html[all_html.find("<body>"):]