datasette/tests/test_template_context.py

"""
Tests for the documented template context - the contract that custom
template authors can rely on for Datasette 1.0.
"""

import html
import json
import pathlib
from dataclasses import dataclass, field

import pytest

from datasette.app import Datasette, TEMPLATE_BASE_CONTEXT
from datasette.extras import ExtraScope
from datasette.fixtures import write_fixture_database
from datasette.template_contexts import PAGES, documented_context_keys
from datasette.views import Context


def test_documented_fields():
    @dataclass
    class DemoContext(Context):
        name: str = field(metadata={"help": "The name"})
        count: int = field(metadata={"help": "How many there are"})

    fields = DemoContext.documented_fields()
    assert [(f.name, f.type_name, f.help) for f in fields] == [
        ("name", "str", "The name"),
        ("count", "int", "How many there are"),
    ]


@pytest.mark.parametrize("klass", PAGES.values(), ids=lambda klass: klass.__name__)
def test_context_class_fields_all_have_help(klass):
    for context_field in klass.documented_fields():
        assert context_field.help, "{}.{} is missing documentation".format(
            klass.__name__, context_field.name
        )


@pytest.mark.parametrize("klass", PAGES.values(), ids=lambda klass: klass.__name__)
def test_context_class_has_docstring_and_template(klass):
    assert klass.__doc__, "{} is missing a docstring".format(klass.__name__)
    assert klass.template, "{} is missing a template".format(klass.__name__)


def test_extra_field_documentation_comes_from_the_extra_class():
    from datasette.views import extra_field
    from datasette.views.table_extras import CountExtra

    @dataclass
    class DemoContext(Context):
        extras_scope = ExtraScope.TABLE

        count: int = extra_field()
        name: str = field(metadata={"help": "The name"})

    fields = {f.name: f for f in DemoContext.documented_fields()}
    assert fields["count"].help == CountExtra.description
    assert fields["count"].from_extra
    assert fields["name"].help == "The name"
    assert not fields["name"].from_extra


def test_extra_field_must_match_a_registered_extra():
    from datasette.views import extra_field

    @dataclass
    class BadContext(Context):
        extras_scope = ExtraScope.TABLE

        not_a_real_extra: str = extra_field()

    with pytest.raises(KeyError):
        BadContext.documented_fields()


def test_extra_field_must_be_available_for_the_scope():
    from datasette.views import extra_field

    @dataclass
    class WrongScopeContext(Context):
        extras_scope = ExtraScope.ROW

        # count is a TABLE-scope extra, not available for ROW
        count: int = extra_field()

    with pytest.raises(ValueError):
        WrongScopeContext.documented_fields()


@pytest.fixture
def isolate_extra_template_vars_plugins():
    # Datasette instances created with plugins_dir (e.g. the session-scoped
    # ds_client fixture) register their plugins on the global plugin manager
    # for the rest of the process. The contract documents plugin-free
    # Datasette core, so unregister any non-default plugin that adds
    # template variables via the extra_template_vars hook
    from datasette.plugins import pm, DEFAULT_PLUGINS

    hook_plugins = {impl.plugin for impl in pm.hook.extra_template_vars.get_hookimpls()}
    removed = []
    for plugin in list(pm.get_plugins()):
        name = pm.get_name(plugin)
        if name not in DEFAULT_PLUGINS and plugin in hook_plugins:
            pm.unregister(plugin)
            removed.append((plugin, name))
    yield
    for plugin, name in removed:
        pm.register(plugin, name)


@pytest.fixture(scope="module")
def context_ds(tmp_path_factory):
    db_path = tmp_path_factory.mktemp("template-context") / "fixtures.db"
    write_fixture_database(db_path)
    ds = Datasette(
        [str(db_path)],
        settings={"num_sql_threads": 1, "template_debug": True},
        config={
            "databases": {
                "fixtures": {
                    "queries": {
                        "neighborhood_search": {
                            "sql": (
                                "select _neighborhood from facetable "
                                "where _neighborhood like '%' || :text || '%'"
                            ),
                            "title": "Search neighborhoods",
                        }
                    }
                }
            }
        },
    )
    yield ds
    for db in ds.databases.values():
        if not db.is_memory:
            db.close()


async def get_template_context(ds, path):
    sep = "&" if "?" in path else "?"
    response = await ds.client.get(path + sep + "_context=1")
    assert response.status_code == 200, path
    body = html.unescape(response.text.removeprefix("<pre>").removesuffix("</pre>"))
    return json.loads(body)


@pytest.mark.asyncio
@pytest.mark.parametrize(
    "page_name,path",
    (
        ("database", "/fixtures"),
        ("table", "/fixtures/facetable"),
        ("table", "/fixtures/facetable?_city_id__exact=1"),
        ("row", "/fixtures/facetable/1"),
        ("query", "/fixtures/-/query?sql=select+*+from+facetable"),
        ("query", "/fixtures/neighborhood_search?text=cork"),
    ),
)
async def test_template_context_matches_documented_contract(
    context_ds, isolate_extra_template_vars_plugins, page_name, path
):
    # The full contract: every key in the rendered template context is
    # documented, and every documented key is present in the context
    documented = documented_context_keys(page_name)
    actual = set(await get_template_context(context_ds, path))
    undocumented = actual - documented
    no_longer_present = documented - actual
    assert not undocumented, (
        "Undocumented keys in {} template context: {} - add them to the "
        "page's Context class".format(page_name, sorted(undocumented))
    )
    assert not no_longer_present, (
        "Documented keys missing from {} template context: {} - this would "
        "break custom templates".format(page_name, sorted(no_longer_present))
    )


def test_base_context_keys_all_have_docs():
    for name, doc in TEMPLATE_BASE_CONTEXT.items():
        assert doc, "Base context key {} is missing docs".format(name)


def test_template_context_docs_cover_every_documented_key():
    docs_path = pathlib.Path(__file__).parent.parent / "docs" / "template_context.rst"
    assert docs_path.exists(), "docs/template_context.rst is missing"
    docs = docs_path.read_text()
    for name in TEMPLATE_BASE_CONTEXT:
        assert "``{}``".format(name) in docs, name
    for page_name, klass in PAGES.items():
        title = "{} page".format(klass.__name__.removesuffix("Context"))
        assert title in docs, title
        for context_field in klass.documented_fields():
            assert "``{}``".format(context_field.name) in docs, "{} ({} page)".format(
                context_field.name, page_name
            )