Allow empty title:

Allow empty title for code snippets. It may
be useful for short code fragments.

codeinclude/plugin.py

@@ -34,7 +34,14 @@
 
 
 def get_substitute(page, title, filename, lines, block, inside_block):
+    # Compute the fence header
+    lang_code = get_lang_class(filename)
+    header = lang_code
+    title = title.strip()
+    if len(title) > 0:
+        header += f' tab="{title}"'
 
+    # Select the code content
     page_parent_dir = os.path.dirname(page.file.abs_src_path)
     import_path = os.path.join(page_parent_dir, filename)
     with open(import_path) as f:
@@ -45,9 +52,9 @@ def get_substitute(page, title, filename, lines, block, inside_block):
     )
 
     dedented = textwrap.dedent(selected_content)
-    lang_code = get_lang_class(filename)
+
     return f'''
-```{lang_code} tab="{title}"
+```{header}
 {dedented}
 ```
 

tests/codeinclude/test_plugin.py

@@ -31,6 +31,17 @@
 
 """
 
+EMPTY_TITLE_MARKDOWN_EXAMPLE = """
+# hello world
+
+some text before
+<!--codeinclude-->
+[](Foo.java)
+<!--/codeinclude-->
+and some text after
+
+"""
+
 c = Config(schema=DEFAULT_SCHEMA)
 c["site_url"] = "http://example.org/"
 
@@ -85,3 +96,23 @@ def test_multi_tab_case(self):
                                   and some text after
                                   """).strip(),
                          result.strip())
+
+    def test_empty_title_case(self):
+        plugin = CodeIncludePlugin()
+        result = plugin.on_page_markdown(EMPTY_TITLE_MARKDOWN_EXAMPLE, PAGE_EXAMPLE, dict())
+
+        print(result)
+        self.assertEqual(textwrap.dedent("""
+                                  # hello world
+
+                                  some text before
+
+                                  ```java
+                                  public class Foo {
+
+                                  }
+                                  ```
+
+                                  and some text after
+                                  """).strip(),
+                         result.strip())