[css-text] Further test coverage updates

Author: frivoal

css-text-3/Overview.bs

@@ -3816,7 +3816,11 @@ Unexpandable Text</h4>
     <p>If the inline contents of a line cannot be stretched to the full width of the line box,
       then they must be aligned as specified by the 'text-align-last' property.
       (If 'text-align-last' is ''justify'', then
-       they must be aligned as for ''center''.)
+      they must be aligned as for ''center''.)
+
+      <wpt>
+        text-align/text-align-last-empty-inline.html
+      </wpt>
 
 <h4 id="justify-cursive">
 Cursive Scripts</h4>

css-text-3/test-coverage.html

@@ -366,12 +366,12 @@ <h4 id="handling-symbols-and-punctuation">6.4.2 <a href="https://drafts.csswg.or
 
 <h4 id="unexpandable-text">6.4.3 <a href="https://drafts.csswg.org/css-text-3/#justify-limits">Unexpandable Text</a></h4>
 
-<p>No tests.
-
+<p>Basic coverage.
 <p>Missing tests:
 
 <ul>
-	<li>TBD…
+	<li>Values of text-align-last other than justify
+	<li>A broader range of non-stretchable content that just an empty span with padding
 </ul>
 
 <h4 id="cursive-scripts">6.4.4 <a href="https://drafts.csswg.org/css-text-3/#justify-cursive">Cursive Scripts</a></h4>