intersphinx role: new inventory parsing from role name

tests/roots/test-ext-intersphinx-role/index.rst

@@ -14,8 +14,31 @@
 - ``module10`` is only defined here, but should still not be resolved to:
   :external:py:mod:`module10`
 
-
 - a function in inv:
   :external:py:func:`module1.func`
 - a method, but with old style inventory prefix, which shouldn't work:
   :external:py:meth:`inv:Foo.bar`
+- a non-existing role:
+  :external:py:nope:`something`
+
+.. default-domain:: cpp
+
+- a type where the default domain is used to find the role:
+  :external:type:`std::uint8_t`
+- a non-existing role in default domain:
+  :external:nope:`somethingElse`
+
+- two roles in ``std`` which can be found without a default domain:
+
+  - :external:doc:`docname`
+  - :external:option:`ls -l`
+
+
+- a function with explicit inventory:
+  :external:inv+c:func:`CFunc`
+- a class with explicit non-existing inventory, which also has upper-case in name:
+  :external:invNope+cpp:class:`foo::Bar`
+
+
+- explicit title:
+  :external:cpp:type:`FoonsTitle <foons>`

tests/test_ext_intersphinx.py

@@ -552,3 +552,20 @@ def test_intersphinx_role(app, warning):
 
     assert html.format('sub/foo.html#module1.func') in content
     assert "WARNING: external py:meth reference target not found: inv:Foo.bar" in wStr
+
+    assert "WARNING: role for external cross-reference not found: py:nope" in wStr
+
+    # default domain
+    assert html.format('index.html#std_uint8_t') in content
+    assert "WARNING: role for external cross-reference not found: nope" in wStr
+
+    # std roles without domain prefix
+    assert html.format('docname.html') in content
+    assert html.format('index.html#cmdoption-ls-l') in content
+
+    # explicit inventory
+    assert html.format('cfunc.html#CFunc') in content
+    #assert "WARNING: inventory for external cross-reference not found: invNope" in wStr
+
+    # explicit title
+    assert html.format('index.html#foons') in content