tests: add test cases for abstract_delimiter

One thing not entirely obvious from the changes is that
tests/fixtures/docs/page_without_meta_early_delimiter.md
together with test_simple_build_item_length_unlimited() checks the
priority of abstract_chars_count: -1 versus abstract_delimiter.

Author: tiosgz

tests/fixtures/docs/page_without_meta_early_delimiter.md

@@ -0,0 +1,5 @@
+# Page without meta with early delimiter
+
+<!-- more -->
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

tests/fixtures/mkdocs_item_delimiter_empty.yml

@@ -0,0 +1,23 @@
+# Project information
+site_name: MkDocs RSS Plugin - TEST
+site_description: Basic setup to test against MkDocs RSS plugin
+site_author: Julien Moura (Guts)
+site_url: https://guts.github.io/mkdocs-rss-plugin
+copyright: "Guts - In Geo Veritas"
+
+# Repository
+repo_name: "guts/mkdocs-rss-plugin"
+repo_url: "https://github.com/guts/mkdocs-rss-plugin"
+
+use_directory_urls: true
+
+plugins:
+  - rss:
+      abstract_delimiter: ""
+
+theme:
+  name: readthedocs
+
+# Extensions to enhance markdown
+markdown_extensions:
+  - meta

tests/test_build.py

@@ -403,9 +403,55 @@ def test_simple_build_item_length_unlimited(self):
                     "Page without meta with short text",
                     "Blog sample",
                 ):
-                    self.assertGreaterEqual(
-                        len(feed_item.description), 150, feed_item.title
-                    )
+                    self.assertGreater(len(feed_item.description), 150, feed_item.title)
+
+    def test_simple_build_item_delimiter(self):
+        with tempfile.TemporaryDirectory() as tmpdirname:
+            cli_result = self.build_docs_setup(
+                testproject_path="docs",
+                mkdocs_yml_filepath=Path("tests/fixtures/mkdocs_minimal.yml"),
+                output_path=tmpdirname,
+                strict=True,
+            )
+            if cli_result.exception is not None:
+                e = cli_result.exception
+                logger.debug(format_exception(type(e), e, e.__traceback__))
+
+            self.assertEqual(cli_result.exit_code, 0)
+            self.assertIsNone(cli_result.exception)
+
+            # created items
+            feed_parsed = feedparser.parse(Path(tmpdirname) / OUTPUT_RSS_FEED_CREATED)
+            self.assertEqual(feed_parsed.bozo, 0)
+
+            for feed_item in feed_parsed.entries:
+                if feed_item.title in ("Page without meta with early delimiter",):
+                    self.assertLess(len(feed_item.description), 50, feed_item.title)
+
+    def test_simple_build_item_delimiter_empty(self):
+        with tempfile.TemporaryDirectory() as tmpdirname:
+            cli_result = self.build_docs_setup(
+                testproject_path="docs",
+                mkdocs_yml_filepath=Path(
+                    "tests/fixtures/mkdocs_item_delimiter_empty.yml"
+                ),
+                output_path=tmpdirname,
+                strict=True,
+            )
+            if cli_result.exception is not None:
+                e = cli_result.exception
+                logger.debug(format_exception(type(e), e, e.__traceback__))
+
+            self.assertEqual(cli_result.exit_code, 0)
+            self.assertIsNone(cli_result.exception)
+
+            # created items
+            feed_parsed = feedparser.parse(Path(tmpdirname) / OUTPUT_RSS_FEED_CREATED)
+            self.assertEqual(feed_parsed.bozo, 0)
+
+            for feed_item in feed_parsed.entries:
+                if feed_item.title in ("Page without meta with early delimiter",):
+                    self.assertGreater(len(feed_item.description), 150, feed_item.title)
 
     def test_simple_build_locale_with_territory(self):
         with tempfile.TemporaryDirectory() as tmpdirname: