add docs and tests for unresolved param variables (#78)

Author: joshuadavidthomas

docs/params.md

@@ -192,7 +192,8 @@ Both attributes and properties support literal (quoted) and dynamic (unquoted) v
 The rules for value resolution are:
 
 - Quoted values (`"value"` or `'value'`) are treated as literal strings
-- Unquoted values are resolved from the template context
+- Unquoted values are first attempted to be resolved from the template context
+    - If resolution fails, the literal value is used as a fallback
 - Boolean values can be passed directly (`disabled=True`) or as strings (`disabled="True"`)
 - Both attributes and properties follow these same resolution rules
 
@@ -238,6 +239,20 @@ Renders as:
 <button class="btn-secondary" variant="small" disabled>Click me</button>
 ```
 
+If an unquoted value cannot be resolved from the context, it falls back to using the literal string:
+
+```htmldjango
+{% bird button class=undefined_class %}
+    Click me
+{% endbird %}
+```
+
+With empty context, renders as:
+
+```html
+<button class="undefined_class">Click me</button>
+```
+
 You can also access nested attributes using dot notation:
 
 ```htmldjango

tests/templatetags/test_bird.py

@@ -202,6 +202,24 @@ def test_rendered_name(
                 {"btn": {"class": "btn-success"}},
                 '<button class="btn.class">Click me</button>',
             ),
+            (
+                "<button {{ attrs }}>Click me</button>",
+                "{% bird button class=undefined_class %}Click me{% endbird %}",
+                {},
+                '<button class="undefined_class">Click me</button>',
+            ),
+            (
+                "<button {{ attrs }}>Click me</button>",
+                "{% bird button class=missing.attr %}Click me{% endbird %}",
+                {},
+                '<button class="missing.attr">Click me</button>',
+            ),
+            (
+                "<button {{ attrs }}>Click me</button>",
+                "{% bird button class=user.preferences.theme %}Click me{% endbird %}",
+                {"user": {"preferences": {}}},
+                '<button class="user.preferences.theme">Click me</button>',
+            ),
         ],
     )
     def test_rendered_attrs(
@@ -380,6 +398,30 @@ def get_template_libraries(self, libraries):
                 {"active_class": "active"},
                 "<button class='active'>Click me</button>",
             ),
+            (
+                "{% bird:prop class %}<button class='{{ props.class }}'>{{ slot }}</button>",
+                "{% bird button class=undefined_class %}Click me{% endbird %}",
+                {},
+                "<button class='undefined_class'>Click me</button>",
+            ),
+            (
+                "{% bird:prop class %}<button class='{{ props.class }}'>{{ slot }}</button>",
+                "{% bird button class=missing.attr %}Click me{% endbird %}",
+                {},
+                "<button class='missing.attr'>Click me</button>",
+            ),
+            (
+                "{% bird:prop class %}<button class='{{ props.class }}'>{{ slot }}</button>",
+                "{% bird button class=user.preferences.theme %}Click me{% endbird %}",
+                {"user": {"preferences": {}}},
+                "<button class='user.preferences.theme'>Click me</button>",
+            ),
+            (
+                "{% bird:prop class='fallback' %}<button class='{{ props.class }}'>{{ slot }}</button>",
+                "{% bird button class=undefined_class %}Click me{% endbird %}",
+                {},
+                "<button class='undefined_class'>Click me</button>",
+            ),
         ],
     )
     def test_with_props(

tests/test_params.py

@@ -18,6 +18,9 @@ class TestValue:
             (Value(None), {}, None),
             (Value("True"), {}, True),
             (Value("False"), {}, None),
+            (Value("undefined", quoted=False), {}, "undefined"),
+            (Value("foo.bar", quoted=False), {}, "foo.bar"),
+            (Value("foo.bar", quoted=False), {"foo": {}}, "foo.bar"),
         ],
     )
     def test_resolve(self, value, context, expected):
@@ -46,6 +49,21 @@ class TestParam:
                 {"item": {"name": "value"}},
                 'class="item.name"',
             ),
+            (
+                Param(name="class", value=Value("undefined", quoted=False)),
+                {},
+                'class="undefined"',
+            ),
+            (
+                Param(name="class", value=Value("foo.bar", quoted=False)),
+                {},
+                'class="foo.bar"',
+            ),
+            (
+                Param(name="class", value=Value("foo.bar", quoted=False)),
+                {"foo": {}},
+                'class="foo.bar"',
+            ),
         ],
     )
     def test_render_attr(self, param, context, expected):
@@ -79,6 +97,21 @@ def test_render_attr(self, param, context, expected):
                 {"user": {"name": "Alice"}},
                 "user.name",
             ),
+            (
+                Param(name="class", value=Value("undefined", quoted=False)),
+                {},
+                "undefined",
+            ),
+            (
+                Param(name="data", value=Value("user.name", quoted=False)),
+                {},
+                "user.name",
+            ),
+            (
+                Param(name="data", value=Value("user.name", quoted=False)),
+                {"user": {}},
+                "user.name",
+            ),
         ],
     )
     def test_render_prop(self, param, context, expected):
@@ -144,6 +177,24 @@ class TestParams:
                 {"class": "dynamic"},
                 [],
             ),
+            (
+                Params(
+                    attrs=[Param(name="class", value=Value("undefined", quoted=False))]
+                ),
+                [PropNode(name="class", default=None, attrs=[])],
+                {},
+                {"class": "undefined"},
+                [],
+            ),
+            (
+                Params(
+                    attrs=[Param(name="class", value=Value("user.name", quoted=False))]
+                ),
+                [PropNode(name="class", default=None, attrs=[])],
+                {},
+                {"class": "user.name"},
+                [],
+            ),
         ],
     )
     def test_render_props(
@@ -186,6 +237,27 @@ def test_render_props(
                 {"var": "dynamic"},
                 'class="dynamic"',
             ),
+            (
+                Params(
+                    attrs=[Param(name="class", value=Value("undefined", quoted=False))]
+                ),
+                {},
+                'class="undefined"',
+            ),
+            (
+                Params(
+                    attrs=[Param(name="class", value=Value("user.name", quoted=False))]
+                ),
+                {},
+                'class="user.name"',
+            ),
+            (
+                Params(
+                    attrs=[Param(name="class", value=Value("user.name", quoted=False))]
+                ),
+                {"user": {}},
+                'class="user.name"',
+            ),
         ],
     )
     def test_render_attrs(self, params, context, expected):