add tests for config, fix failing test on Site

omicron/ssg/cli.py

@@ -2,7 +2,8 @@ import argparse
 import logging
 import sys
 from omicron.ssg.output import OutputError
-from omicron.ssg.site import ConfigError, Site
+from omicron.ssg.site import Site
+from omicron.ssg.config import ConfigError
 from pathlib import Path
 
 

omicron/ssg/config.py

@@ -0,0 +1,101 @@
+from dataclasses import dataclass
+from pathlib import Path
+import logging
+import yaml
+from urllib.parse import urlparse
+
+log = logging.getLogger(__name__)
+
+
+class ConfigError(RuntimeError):
+    pass
+
+
+DEFAULT_ITEMS_PER_PAGE = 20
+
+
+@dataclass
+class SiteConfig:
+    name: str
+    origin: str
+    base_dir: Path
+    items_per_page: int
+    template: str
+
+    @staticmethod
+    def parse_base_url(value: str | None) -> tuple[str, Path]:
+        if not value:
+            return ("", Path("/"))
+        try:
+            parsed = urlparse(value)
+        except ValueError as e:
+            raise ConfigError("invalid url format in base_url") from e
+        if parsed.scheme and parsed.netloc:
+            origin = f"{parsed.scheme}://{parsed.netloc}"
+        elif parsed.netloc:
+            origin = f"//{parsed.netloc}"
+        else:
+            origin = ""
+
+        if parsed.path:
+            path = Path(parsed.path)
+        else:
+            path = Path("/")
+
+        if not path.is_absolute():
+            raise ConfigError("base_url config property must not be a relative path")
+
+        return (origin, path)
+
+    @staticmethod
+    def from_file(path: Path) -> SiteConfig:
+        log.debug("Reading config file %s", path)
+        try:
+            with open(path, "r") as f:
+                config = yaml.safe_load(f)
+        except FileNotFoundError as e:
+            raise ConfigError("config file missing, not a valid ossg directory") from e
+        except yaml.YAMLError as e:
+            raise ConfigError("config file must be a valid YAML file") from e
+        if not isinstance(config, dict):
+            raise ConfigError(
+                "config file must be a YAML mapping with string keys and int/str values"
+            )
+        for k, v in config.items():
+            if type(k) != str or type(v) not in [str, int]:
+                raise ConfigError(
+                    "config file must be a YAML mapping with string keys and int/str values"
+                )
+        return SiteConfig.from_dict(config)
+
+    @staticmethod
+    def from_dict(config: dict[str, str | int]) -> SiteConfig:
+        name = config.get("name")
+        template = config.get("template")
+        base_url = config.get("base_url")
+        items_per_page = config.get("items_per_page", DEFAULT_ITEMS_PER_PAGE)
+
+        if name is None:
+            raise ConfigError("config file must contain a name property")
+        if template is None:
+            raise ConfigError("config file must contain a template property")
+        if base_url is not None and not isinstance(base_url, str):
+            raise ConfigError("base_url config property must be a string")
+        if not isinstance(name, str):
+            raise ConfigError("name config property must be a string")
+        if not isinstance(template, str):
+            raise ConfigError("template config property must be a string")
+        if not isinstance(items_per_page, int) or items_per_page < 1:
+            raise ConfigError(
+                "items_per_page config property must be a positive integer"
+            )
+
+        origin, base_dir = SiteConfig.parse_base_url(base_url)
+
+        return SiteConfig(
+            name=name,
+            origin=origin,
+            base_dir=base_dir,
+            items_per_page=items_per_page,
+            template=template,
+        )

omicron/ssg/output/directory.py

@@ -14,7 +14,7 @@ else:
 class Directory(Output):
     def __init__(self, site: Site, destination: Path):
         super().__init__(site, destination)
-        url_path = Path("/") / site.base_dir / destination
+        url_path = Path("/") / site.config.base_dir / destination
         # rebuild url because Output strips /index.html which is a valid dir
         self.url = url_path.as_posix()
 

omicron/ssg/output/feed.py

@@ -46,8 +46,9 @@ class Feed(Output):
         return Path(label) / file
 
     def write(self) -> None:
-        feed_url = f"{self.site.origin}{self.url}"
-        title = f"{self.site.name} — {self.label}" if self.label else self.site.name
+        config = self.site.config
+        feed_url = f"{config.origin}{self.url}"
+        title = f"{config.name} — {self.label}" if self.label else config.name
         updated = max(
             (c.updated or c.created for c in self.items), default=date.today()
         )
@@ -60,7 +61,7 @@ class Feed(Output):
 
         for item in self.items:
             entry = SubElement(feed, "entry")
-            item_url = f"{self.site.origin}{item.url}"
+            item_url = f"{config.origin}{item.url}"
             SubElement(entry, "title").text = item.title
             SubElement(entry, "id").text = item_url
             SubElement(entry, "link", href=item_url)

omicron/ssg/output/index.py

@@ -89,14 +89,13 @@ def make_index_pages(
 
 
 def discover_index(site: Site) -> list[Index]:
+    items_per_page = site.config.items_per_page
     outputs: list[Index] = []
-    outputs.extend(
-        make_index_pages(site, site.content, "root", None, site.items_per_page)
-    )
+    outputs.extend(make_index_pages(site, site.content, "root", None, items_per_page))
     for section, items in site.by_section.items():
         outputs.extend(
-            make_index_pages(site, items, "section", section, site.items_per_page)
+            make_index_pages(site, items, "section", section, items_per_page)
         )
     for tag, items in site.by_tag.items():
-        outputs.extend(make_index_pages(site, items, "tag", tag, site.items_per_page))
+        outputs.extend(make_index_pages(site, items, "tag", tag, items_per_page))
     return outputs

omicron/ssg/output/output.py

@@ -26,7 +26,7 @@ class Output(ABC):
             raise OutputError("destination path must be normalized")
         self.destination = destination
 
-        url = site.base_dir / destination
+        url = site.config.base_dir / destination
         if url.name == "index.html":
             url = url.parent
         self.url = url.as_posix()

omicron/ssg/output/sitemap.py

@@ -27,7 +27,7 @@ class Sitemap(Output):
                 continue
 
             url = SubElement(urlset, "url")
-            SubElement(url, "loc").text = f"{self.site.origin}{entry.url}"
+            SubElement(url, "loc").text = f"{self.site.config.origin}{entry.url}"
             if isinstance(entry, Content):
                 lastmod = entry.updated or entry.created
                 SubElement(url, "lastmod").text = lastmod.isoformat()

omicron/ssg/site.py

@@ -1,7 +1,6 @@
 import logging
 import shutil
-from typing import Any, Literal, cast
-from urllib.parse import urlparse
+from typing import Literal
 
 from omicron.ssg.output import (
     Output,
@@ -22,18 +21,14 @@ from omicron.ssg.output import (
     discover_feeds,
 )
 from omicron.ssg.markdown import highlight_style
+from omicron.ssg.config import SiteConfig, ConfigError
 
 from pathlib import Path
-import yaml
 from jinja2 import Environment, FileSystemLoader
 
 log = logging.getLogger(__name__)
 
 
-class ConfigError(RuntimeError):
-    pass
-
-
 class Site:
     def __init__(self, site: Path, drafts: bool = False):
         self.site_path = site.resolve()
@@ -47,50 +42,11 @@ class Site:
         self.by_section: dict[str, list[Content]] = {}
         self.tags_by_count: list[tuple[str, int]] = []
 
-        config = self.read_config()
-        self.name: str = config["name"]
-        self.template: str = config["template"]
-        self.items_per_page: int = int(config.get("items_per_page", 20))
-        self.origin, self.base_dir = Site.parse_base_url(config.get("base_url"))
-        self.template_path: Path = Site.resolve_template_path(self.template)
+        self.config = SiteConfig.from_file(site / "config.yml")
+        self.template_path: Path = Site.resolve_template_path(self.config.template)
         self.output_path: Path = self.site_path / "output"
         self.jinja_env = Environment(loader=FileSystemLoader(self.template_path))
 
-    def read_config(self) -> dict[str, Any]:
-        config_path = self.site_path / "config.yml"
-        log.debug("Reading config file %s", config_path)
-        try:
-            with open(config_path, "r") as f:
-                config = yaml.safe_load(f)
-        except FileNotFoundError:
-            raise ConfigError("config file missing, not a valid ossg directory")
-        if not isinstance(config, dict) or not all(isinstance(k, str) for k in config):
-            raise ConfigError("config file must be a YAML mapping with string keys")
-        if "name" not in config:
-            raise ConfigError("name value missing from config")
-        if "template" not in config:
-            raise ConfigError("template value missing from config")
-        return cast(dict[str, Any], config)
-
-    @staticmethod
-    def parse_base_url(value: str | None) -> tuple[str, Path]:
-        if not value:
-            return ("", Path("/"))
-        parsed = urlparse(value)
-        if parsed.scheme and parsed.netloc:
-            origin = f"{parsed.scheme}://{parsed.netloc}"
-        elif parsed.netloc:
-            origin = f"//{parsed.netloc}"
-        else:
-            origin = ""
-
-        if parsed.path:
-            path = Path(parsed.path)
-        else:
-            path = Path("/")
-
-        return (origin, path)
-
     @staticmethod
     def resolve_template_path(template: str) -> Path:
         path = Path(__file__).parent / "templates" / template
@@ -137,12 +93,12 @@ class Site:
         self.by_source[content.source] = content
 
     def home_url(self) -> str:
-        return self.base_dir.as_posix()
+        return self.config.base_dir.as_posix()
 
     def url_for(self, path: str) -> str:
         if Path(path).is_absolute():
             raise OutputError("path must be relative")
-        return (self.base_dir / path).as_posix()
+        return (self.config.base_dir / path).as_posix()
 
     def section_url(self, section: str) -> str:
         path = Index.build_path("section", 1, section)
@@ -204,7 +160,7 @@ class Site:
         tags_page = discover_tags(self)
         self.add_by_path(tags_page)
         self.other_outputs.append(tags_page)
-        if self.origin:
+        if self.config.origin:
             sitemap = Sitemap(self)
             self.add_by_path(sitemap)
             self.other_outputs.append(sitemap)
@@ -222,13 +178,11 @@ class Site:
         log.info("Removed %s", self.output_path)
 
     def build(self) -> None:
-        if not self.origin:
+        if not self.config.origin:
             log.warning(
                 "base_url config value is missing a domain name, "
                 "can't add canonical url to content"
             )
-        if not self.base_dir.is_absolute():
-            raise ConfigError("base_url config value must be an absolute path")
         self.discover()
         outputs: list[Output] = [*self.directories, *self.content]
         for output in sorted(outputs, key=lambda o: o.destination.as_posix()):

omicron/ssg/templates/plain/article.html

@@ -1,10 +1,10 @@
 {% extends "base.html" %}
 
-{% block title %}{{ page.title }} — {{ site.name }}{% endblock %}
+{% block title %}{{ page.title }} — {{ site.config.name }}{% endblock %}
 
 {% block breadcrumb %}
 <nav aria-label="breadcrumb">
-    <a href="{{ site.home_url() }}">{{ site.name }}</a> ›
+    <a href="{{ site.home_url() }}">{{ site.config.name }}</a> ›
     <a href="{{ site.section_url(page.section) }}">{{ page.section }}</a> ›
     {{ page.title }}
 </nav>

omicron/ssg/templates/plain/base.html

@@ -3,22 +3,22 @@
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
-    <title>{% block title %}{{ site.name }}{% endblock %}</title>
+    <title>{% block title %}{{ site.config.name }}{% endblock %}</title>
     <link rel="stylesheet" href="{{ site.url_for('assets/style.css') }}">
     <link rel="stylesheet" href="{{ site.url_for('assets/pygments.css') }}">
-    {% if site.origin %}<link rel="canonical" href="{{ site.origin }}{{ page.url }}">{% endif %}
-    {% if site.feed_url("root", None) %}<link rel="alternate" type="application/atom+xml" title="{{ site.name }}" href="{{ site.feed_url('root', None) }}">{% endif %}
+    {% if site.config.origin %}<link rel="canonical" href="{{ site.config.origin }}{{ page.url }}">{% endif %}
+    {% if site.feed_url("root", None) %}<link rel="alternate" type="application/atom+xml" title="{{ site.config.name }}" href="{{ site.feed_url('root', None) }}">{% endif %}
     {% block head %}{% endblock %}
 </head>
 <body>
     <header>
-        {% block breadcrumb %}<a href="{{ site.home_url() }}">{{ site.name }}</a>{% endblock %}
+        {% block breadcrumb %}<a href="{{ site.home_url() }}">{{ site.config.name }}</a>{% endblock %}
     </header>
     <main>
         {% block main %}{% endblock %}
     </main>
     <footer>
-        <p>{{ site.name }}</p>
+        <p>{{ site.config.name }}</p>
     </footer>
 </body>
 </html>

omicron/ssg/templates/plain/index.html

@@ -1,6 +1,6 @@
 {% extends "base.html" %}
 
-{% block title %}{% if page.label %}{{ page.label }} — {% endif %}{{ site.name }}{% if page.page_num > 1 %} — Page {{ page.page_num }}{% endif %}{% endblock %}
+{% block title %}{% if page.label %}{{ page.label }} — {% endif %}{{ site.config.name }}{% if page.page_num > 1 %} — Page {{ page.page_num }}{% endif %}{% endblock %}
 
 {% block head %}
 {% if page.page_num > 1 %}<meta name="robots" content="noindex, follow">{% endif %}
@@ -12,12 +12,12 @@
 {% block breadcrumb %}
 {% if page.kind == "section" %}
 <nav aria-label="breadcrumb">
-    <a href="{{ site.home_url() }}">{{ site.name }}</a> ›
+    <a href="{{ site.home_url() }}">{{ site.config.name }}</a> ›
     {{ page.label }}
 </nav>
 {% elif page.kind == "tag" %}
 <nav aria-label="breadcrumb">
-    <a href="{{ site.home_url() }}">{{ site.name }}</a> ›
+    <a href="{{ site.home_url() }}">{{ site.config.name }}</a> ›
     <a href="{{ site.tags_url() }}">Tags</a> ›
     {{ page.label }}
 </nav>

omicron/ssg/templates/plain/tags.html

@@ -1,10 +1,10 @@
 {% extends "base.html" %}
 
-{% block title %}Tags — {{ site.name }}{% endblock %}
+{% block title %}Tags — {{ site.config.name }}{% endblock %}
 
 {% block breadcrumb %}
 <nav aria-label="breadcrumb">
-    <a href="{{ site.home_url() }}">{{ site.name }}</a> ›
+    <a href="{{ site.home_url() }}">{{ site.config.name }}</a> ›
     Tags
 </nav>
 {% endblock %}

pyproject.toml

@@ -41,6 +41,7 @@ source = ["omicron"]
 
 [tool.coverage.report]
 show_missing = true
+exclude_also = ["@(abc\\.)?abstractmethod"]
 
 [tool.setuptools.packages.find]
 where = ["."]

tests/data/sites/draft_content/config.yml

@@ -0,0 +1,2 @@
+name: Draft Content Test
+template: plain

tests/data/sites/draft_content/content/draft.md

@@ -0,0 +1,9 @@
+---
+type: article
+section: posts
+slug: draft-post
+title: Draft
+date: 2026-08-28
+draft: true
+---
+Draft.

tests/data/sites/draft_content/content/published.md

@@ -0,0 +1,8 @@
+---
+type: article
+section: posts
+slug: published
+title: Published
+date: 2026-08-28
+---
+Published.

tests/data/sites/duplicate_slug/config.yml

@@ -0,0 +1,2 @@
+name: Duplicate Slug Test
+template: plain

tests/data/sites/duplicate_slug/content/first.md

@@ -0,0 +1,8 @@
+---
+type: article
+section: posts
+slug: hello
+title: First
+date: 2026-08-28
+---
+First.

tests/data/sites/duplicate_slug/content/second.md

@@ -0,0 +1,8 @@
+---
+type: article
+section: posts
+slug: hello
+title: Second
+date: 2026-08-28
+---
+Second.

tests/data/sites/sections/config.yml

@@ -0,0 +1,2 @@
+name: Sections Test
+template: plain

tests/data/sites/sections/content/first-note.md

@@ -0,0 +1,8 @@
+---
+type: article
+section: notes
+slug: first-note
+title: First Note
+date: 2026-08-28
+---
+First note.

tests/data/sites/sections/content/first-post.md

@@ -0,0 +1,8 @@
+---
+type: article
+section: posts
+slug: first-post
+title: First Post
+date: 2026-08-28
+---
+First post.

tests/data/sites/sections/content/second-post.md

@@ -0,0 +1,8 @@
+---
+type: article
+section: posts
+slug: second-post
+title: Second Post
+date: 2026-08-28
+---
+Second post.

tests/data/sites/tags/config.yml

@@ -0,0 +1,2 @@
+name: Tags Test
+template: plain

tests/data/sites/tags/content/no-tags.md

@@ -0,0 +1,8 @@
+---
+type: article
+section: posts
+slug: no-tags
+title: No Tags
+date: 2026-08-28
+---
+No tags.

tests/data/sites/tags/content/one-tag.md

@@ -0,0 +1,9 @@
+---
+type: article
+section: posts
+slug: one-tag
+title: One Tag
+date: 2026-08-28
+tags: [python]
+---
+One tag.

tests/data/sites/tags/content/two-tags.md

@@ -0,0 +1,9 @@
+---
+type: article
+section: posts
+slug: two-tags
+title: Two Tags
+date: 2026-08-28
+tags: [python, testing]
+---
+Two tags.

tests/data/sites/thin_site/config.yml

@@ -0,0 +1,2 @@
+name: test
+template: plain

tests/unit/conftest.py

@@ -0,0 +1,28 @@
+import shutil
+from pathlib import Path
+import pytest
+from omicron.ssg.site import Site
+
+DATA_SITES = Path(__file__).parent.parent / "data" / "sites"
+
+
+@pytest.fixture
+def site_dir(tmp_path):
+    def _make(name):
+        path = tmp_path / name
+        shutil.copytree(
+            DATA_SITES / name,
+            path,
+            ignore=shutil.ignore_patterns("output", "build.log"),
+        )
+        return path
+
+    return _make
+
+
+@pytest.fixture
+def make_site(site_dir):
+    def _make(name, **kwargs):
+        return Site(site_dir(name), **kwargs)
+
+    return _make

tests/unit/test_config.py

@@ -0,0 +1,188 @@
+from pathlib import Path
+import pytest
+from omicron.ssg.config import SiteConfig, ConfigError, DEFAULT_ITEMS_PER_PAGE
+
+
+@pytest.mark.parametrize(
+    "value, expected_origin, expected_path",
+    [
+        (None, "", Path("/")),
+        ("http://example.com/blog", "http://example.com", Path("/blog")),
+        ("http://example.com", "http://example.com", Path("/")),
+        ("//example.com/blog", "//example.com", Path("/blog")),
+        ("/blog", "", Path("/blog")),
+    ],
+)
+def test_parse_base_url(value, expected_origin, expected_path):
+    origin, path = SiteConfig.parse_base_url(value)
+    assert origin == expected_origin
+    assert path == expected_path
+
+
+@pytest.mark.parametrize(
+    "value, expected_message",
+    [
+        ("https://[::1", "invalid url format"),
+        ("relative/path", "relative path"),
+    ],
+)
+def test_parse_base_url_error(value, expected_message):
+    with pytest.raises(ConfigError, match=expected_message):
+        origin, path = SiteConfig.parse_base_url(value)
+
+
+def test_from_dict_minimal():
+    config = SiteConfig.from_dict({"name": "My Site", "template": "plain"})
+
+    assert config.name == "My Site"
+    assert config.template == "plain"
+    assert config.items_per_page == DEFAULT_ITEMS_PER_PAGE
+    assert config.origin == ""
+    assert config.base_dir == Path("/")
+
+
+def test_from_dict_full():
+    config = SiteConfig.from_dict(
+        {
+            "name": "My Site",
+            "template": "plain",
+            "base_url": "http://example.com/blog",
+            "items_per_page": 42,
+        }
+    )
+
+    assert config.name == "My Site"
+    assert config.template == "plain"
+    assert config.items_per_page == 42
+    assert config.origin == "http://example.com"
+    assert config.base_dir == Path("/blog")
+
+
+MISSING = object()
+
+
+@pytest.mark.parametrize(
+    "overrides, expected_message",
+    [
+        ({"name": MISSING}, "must contain a name property"),
+        ({"template": MISSING}, "must contain a template property"),
+        ({"name": 123}, "name config property must be a string"),
+        ({"template": 123}, "template config property must be a string"),
+        ({"base_url": 123}, "base_url config property must be a string"),
+        ({"base_url": "relative/path"}, "relative path"),
+        ({"base_url": "https://[::1"}, "invalid url format"),
+        (
+            {"items_per_page": "10"},
+            "items_per_page config property must be a positive integer",
+        ),
+        (
+            {"items_per_page": 0},
+            "items_per_page config property must be a positive integer",
+        ),
+        (
+            {"items_per_page": -1},
+            "items_per_page config property must be a positive integer",
+        ),
+    ],
+)
+def test_from_dict_error(overrides, expected_message):
+    config = {"name": "My Site", "template": "plain"}
+    for key, value in overrides.items():
+        if value is MISSING:
+            config.pop(key, None)
+        else:
+            config[key] = value
+
+    with pytest.raises(ConfigError, match=expected_message):
+        SiteConfig.from_dict(config)
+
+
+def test_from_file_minimal(tmp_path):
+    path = tmp_path / "config.yml"
+    path.write_text("name: My Site\ntemplate: plain\n")
+
+    config = SiteConfig.from_file(path)
+
+    assert config.name == "My Site"
+    assert config.template == "plain"
+    assert config.items_per_page == DEFAULT_ITEMS_PER_PAGE
+    assert config.origin == ""
+    assert config.base_dir == Path("/")
+
+
+def test_from_file_full(tmp_path):
+    path = tmp_path / "config.yml"
+    path.write_text(
+        "name: My Site\n"
+        "template: plain\n"
+        "base_url: http://example.com/blog\n"
+        "items_per_page: 42\n"
+    )
+
+    config = SiteConfig.from_file(path)
+
+    assert config.name == "My Site"
+    assert config.template == "plain"
+    assert config.items_per_page == 42
+    assert config.origin == "http://example.com"
+    assert config.base_dir == Path("/blog")
+
+
+def test_from_file_missing(tmp_path):
+    path = tmp_path / "config.yml"
+
+    with pytest.raises(ConfigError, match="config file missing"):
+        SiteConfig.from_file(path)
+
+
+@pytest.mark.parametrize(
+    "yaml_text, expected_message",
+    [
+        ("- a\n- b\n", "must be a YAML mapping"),
+        ("just a string\n", "must be a YAML mapping"),
+        ("123: value\n", "must be a YAML mapping"),
+        ("name: [1, 2]\n", "must be a YAML mapping"),
+        ("name: true\n", "must be a YAML mapping"),
+        (":\n  bad: yaml: here\n", "must be a valid YAML file"),
+        ("template: plain\n", "must contain a name property"),
+        ("name: My Site\n", "must contain a template property"),
+        (
+            "name: 123\ntemplate: plain\n",
+            "name config property must be a string",
+        ),
+        (
+            "name: My Site\ntemplate: 123\n",
+            "template config property must be a string",
+        ),
+        (
+            "name: My Site\ntemplate: plain\nbase_url: 123\n",
+            "base_url config property must be a string",
+        ),
+        (
+            "name: My Site\ntemplate: plain\nbase_url: relative/path\n",
+            "relative path",
+        ),
+        (
+            "name: My Site\ntemplate: plain\nbase_url: https://[::1\n",
+            "invalid url format",
+        ),
+        (
+            'name: My Site\ntemplate: plain\nitems_per_page: "10"\n',
+            "items_per_page config property must be a positive integer",
+        ),
+        (
+            "name: My Site\ntemplate: plain\nitems_per_page: 0\n",
+            "items_per_page config property must be a positive integer",
+        ),
+        (
+            "name: My Site\ntemplate: plain\nitems_per_page: -1\n",
+            "items_per_page config property must be a positive integer",
+        ),
+    ],
+)
+def test_from_file_error(tmp_path, yaml_text, expected_message):
+    path = tmp_path / "config.yml"
+    path.write_text(yaml_text)
+
+    with pytest.raises(ConfigError, match=expected_message):
+        SiteConfig.from_file(path)

tests/unit/test_file.py

@@ -0,0 +1,31 @@
+from pathlib import Path
+from omicron.ssg.output.file import File
+
+
+def test_write_copies_content(make_site, tmp_path):
+    site = make_site("thin_site")
+    source = tmp_path / "source.txt"
+    source.write_text("hello")
+    dest_dir = site.output_path / "assets"
+    dest_dir.mkdir(parents=True)
+
+    file = File(site, Path("assets/copy.txt"), source)
+    file.write()
+
+    dest = dest_dir / "copy.txt"
+    assert dest.read_text() == "hello"
+
+
+def test_write_overwrites_existing_destination(make_site, tmp_path):
+    site = make_site("thin_site")
+    dest = site.output_path / "copy.txt"
+    dest.parent.mkdir(parents=True, exist_ok=True)
+    dest.write_text("old")
+
+    source = tmp_path / "source.txt"
+    source.write_text("new")
+
+    file = File(site, Path("copy.txt"), source)
+    file.write()
+
+    assert dest.read_text() == "new"

tests/unit/test_output.py

@@ -0,0 +1,38 @@
+from pathlib import Path
+import pytest
+from omicron.ssg.output.file import File
+from omicron.ssg.output.output import OutputError
+
+
+def test_absolute_destination_raises(make_site, tmp_path):
+    site = make_site("thin_site")
+    with pytest.raises(OutputError):
+        File(site, Path("/copy.txt"), tmp_path / "source.txt")
+
+
+def test_non_normalized_destination_raises(make_site, tmp_path):
+    site = make_site("thin_site")
+    with pytest.raises(OutputError):
+        File(site, Path("assets/../copy.txt"), tmp_path / "source.txt")
+
+
+def test_site_raises_after_garbage_collection(make_site, tmp_path):
+    site = make_site("thin_site")
+    file = File(site, Path("copy.txt"), tmp_path / "source.txt")
+
+    del site
+
+    with pytest.raises(ReferenceError):
+        file.site
+
+
+def test_url(make_site, tmp_path):
+    site = make_site("thin_site")
+    file = File(site, Path("assets/copy.txt"), tmp_path / "source.txt")
+    assert file.url == "/assets/copy.txt"
+
+
+def test_url_strips_index_html(make_site, tmp_path):
+    site = make_site("thin_site")
+    file = File(site, Path("posts/index.html"), tmp_path / "source.txt")
+    assert file.url == "/posts"

tests/unit/test_site.py

@@ -1,19 +1,192 @@
 from pathlib import Path
 import pytest
-from omicron.ssg.site import Site
+from omicron.ssg.output import ContentError, Directory, OutputError
+from omicron.ssg.site import ConfigError, Site
 
 
-@pytest.mark.parametrize(
-    "value, expected_origin, expected_path",
-    [
-        (None, "", Path("/")),
-        ("http://example.com/blog", "http://example.com", Path("/blog")),
-        ("http://example.com", "http://example.com", Path("/")),
-        ("//example.com/blog", "//example.com", Path("/blog")),
-        ("/blog", "", Path("/blog")),
-    ],
-)
-def test_parse_base_url(value, expected_origin, expected_path):
-    origin, path = Site.parse_base_url(value)
-    assert origin == expected_origin
-    assert path == expected_path
+def test_discover_raises_on_duplicate_destination(make_site):
+    site = make_site("duplicate_slug")
+    with pytest.raises(ContentError):
+        site.discover()
+
+
+def test_discover_creates_content_directories(make_site):
+    site = make_site("main")
+    site.discover()
+
+    assert isinstance(site.by_path[Path("posts")], Directory)
+    assert isinstance(site.by_path[Path("posts/first-post")], Directory)
+
+
+def test_read_config_errors(site_dir):
+    path = site_dir("thin_site")
+    config_path = path / "config.yml"
+
+    config_path.unlink()
+    with pytest.raises(ConfigError, match="config file missing"):
+        Site(path)
+
+    config_path.write_text("- a\n- b\n")
+    with pytest.raises(ConfigError, match="YAML mapping with string keys"):
+        Site(path)
+
+    config_path.write_text("123: value\n")
+    with pytest.raises(ConfigError, match="YAML mapping with string keys"):
+        Site(path)
+
+    config_path.write_text("template: plain\n")
+    with pytest.raises(ConfigError, match="must contain a name property"):
+        Site(path)
+
+    config_path.write_text("name: test\n")
+    with pytest.raises(ConfigError, match="must contain a template property"):
+        Site(path)
+
+
+def test_site_relative_base_url(site_dir):
+    path = site_dir("thin_site")
+    (path / "config.yml").write_text("name: test\ntemplate: plain\nbase_url: blog\n")
+
+    with pytest.raises(ConfigError, match="relative path"):
+        site = Site(path)
+
+
+def test_discover_skips_drafts_by_default(make_site):
+    site = make_site("draft_content")
+    site.discover()
+
+    assert len(site.content) == 1
+    assert site.content[0].title == "Published"
+
+
+def test_discover_includes_drafts_when_enabled(make_site):
+    site = make_site("draft_content", drafts=True)
+    site.discover()
+
+    assert len(site.content) == 2
+
+
+def test_clean_removes_output_directory(make_site):
+    site = make_site("main")
+    site.build()
+    assert site.output_path.exists()
+
+    site.clean()
+    assert not site.output_path.exists()
+
+    site.clean()
+    assert not site.output_path.exists()
+
+
+def test_resolve_template_path_raises_for_missing_template():
+    with pytest.raises(ConfigError, match="not found"):
+        Site.resolve_template_path("does-not-exist")
+
+
+def test_home_url(site_dir):
+    path = site_dir("thin_site")
+    (path / "config.yml").write_text("name: test\ntemplate: plain\n")
+    assert Site(path).home_url() == "/"
+
+    (path / "config.yml").write_text(
+        "name: test\ntemplate: plain\nbase_url: http://example.com/blog\n"
+    )
+    assert Site(path).home_url() == "/blog"
+
+
+def test_url_for(site_dir):
+    path = site_dir("thin_site")
+    (path / "config.yml").write_text(
+        "name: test\ntemplate: plain\nbase_url: http://example.com/blog\n"
+    )
+
+    site = Site(path)
+    assert site.url_for("assets/style.css") == "/blog/assets/style.css"
+
+    with pytest.raises(OutputError, match="must be relative"):
+        site.url_for("/assets/style.css")
+
+
+def test_section_url(site_dir):
+    path = site_dir("sections")
+
+    site = Site(path)
+    site.discover()
+    assert site.section_url("posts") == "/posts"
+    assert site.section_url("notes") == "/notes"
+
+    (path / "config.yml").write_text("name: test\ntemplate: plain\nbase_url: /blog\n")
+    site = Site(path)
+    site.discover()
+    assert site.section_url("posts") == "/blog/posts"
+    assert site.section_url("notes") == "/blog/notes"
+
+
+def test_add_by_section(make_site):
+    site = make_site("sections")
+    site.discover()
+
+    assert set(site.by_section) == {"posts", "notes"}
+    assert {c.title for c in site.by_section["posts"]} == {"First Post", "Second Post"}
+    assert {c.title for c in site.by_section["notes"]} == {"First Note"}
+
+
+def test_feed_url(site_dir):
+    path = site_dir("tags")
+
+    (path / "config.yml").write_text(
+        "name: test\ntemplate: plain\nbase_url: http://example.com\n"
+    )
+    site = Site(path)
+    site.discover()
+    assert site.feed_url("root", None) == "/atom.xml"
+
+    (path / "config.yml").write_text("name: test\ntemplate: plain\n")
+    site = Site(path)
+    site.discover()
+    assert site.feed_url("root", None) is None
+
+
+def test_tag_url(site_dir):
+    path = site_dir("tags")
+
+    site = Site(path)
+    site.discover()
+    assert site.tag_url("python") == "/tags/python"
+
+    (path / "config.yml").write_text("name: test\ntemplate: plain\nbase_url: /blog\n")
+    site = Site(path)
+    site.discover()
+    assert site.tag_url("python") == "/blog/tags/python"
+
+
+def test_tags_url(make_site):
+    site = make_site("tags")
+    site.discover()
+
+    assert site.tags_url() == "/tags"
+
+
+def test_add_by_source(make_site):
+    site = make_site("tags")
+    site.discover()
+
+    assert site.by_source
+    for content in site.content:
+        assert site.by_source[content.source] is content
+
+
+def test_tags_by_count(make_site):
+    site = make_site("tags")
+    site.discover()
+
+    assert site.tags_by_count == [("python", 2), ("testing", 1)]
+
+
+def test_add_by_tag(make_site):
+    site = make_site("tags")
+    site.discover()
+
+    assert set(site.by_tag) == {"python", "testing"}
+    assert {c.title for c in site.by_tag["python"]} == {"One Tag", "Two Tags"}
+    assert {c.title for c in site.by_tag["testing"]} == {"Two Tags"}