Don't use internal templates anymore.

Blag will throw an error if a template is not found locally. The error
message contains an explanation for the user on where to get the missing
templates.

Quickstart will generate templates for the user in the working
directory.

Updated tests appropriately.

tests/conftest.py

@@ -8,18 +8,18 @@ import os
 import pytest
 from jinja2 import Environment, Template
 
-from blag import blag
+from blag import blag, quickstart
 
 
 @pytest.fixture
-def environment() -> Iterator[Environment]:
+def environment(cleandir: str) -> Iterator[Environment]:
     site = {
         'base_url': 'site base_url',
         'title': 'site title',
         'description': 'site description',
         'author': 'site author',
     }
-    env = blag.environment_factory(globals_=dict(site=site))
+    env = blag.environment_factory('templates', globals_=dict(site=site))
     yield env
 
 
@@ -50,7 +50,7 @@ def tag_template(environment: Environment) -> Iterator[Template]:
 
 @pytest.fixture
 def cleandir() -> Iterator[str]:
-    """Create a temporary workind directory and cwd."""
+    """Create a temporary working directory and cwd."""
     config = """
 [main]
 base_url = https://example.com/
@@ -60,13 +60,14 @@ author = a. u. thor
     """
 
     with TemporaryDirectory() as dir:
-        for d in 'content', 'build', 'static', 'templates':
+        for d in 'content', 'build', 'static':
             os.mkdir(f'{dir}/{d}')
         with open(f'{dir}/config.ini', 'w') as fh:
             fh.write(config)
         # change directory
         old_cwd = os.getcwd()
         os.chdir(dir)
+        quickstart.copy_templates()
         yield dir
         # and change back afterwards
         os.chdir(old_cwd)

tests/test_blag.py

@@ -179,9 +179,9 @@ author = a. u. thor
         assert config_parsed['base_url'] == 'https://example.com/'
 
 
-def test_environment_factory() -> None:
+def test_environment_factory(cleandir: str) -> None:
     globals_: dict[str, object] = {'foo': 'bar', 'test': 'me'}
-    env = blag.environment_factory(globals_=globals_)
+    env = blag.environment_factory("templates", globals_=globals_)
     assert env.globals['foo'] == 'bar'
     assert env.globals['test'] == 'me'
 
@@ -299,6 +299,22 @@ foo bar
     assert os.path.exists(f'{args.output_dir}/tags/bar.html')
 
 
+@pytest.mark.parametrize(
+    'template',
+    [
+        'page.html',
+        'article.html',
+        'archive.html',
+        'tags.html',
+        'tag.html',
+    ]
+)
+def test_missing_template_raises(template: str, args: Namespace) -> None:
+    os.remove(f'templates/{template}')
+    with pytest.raises(SystemExit):
+        blag.build(args)
+
+
 def test_main(cleandir: str) -> None:
     blag.main(['build'])