test(template.mustache): nullish coalescing operator

tests/template/test_mustache.py

@@ -1,4 +1,12 @@
-from hyprshade.template.mustache import render
+from typing import Any
+
+import pytest
+
+from hyprshade.template.mustache import NULLISH_COALESCE_LAMBDA_NAME, render
+
+
+def nc(text: str) -> str:
+    return f"{{{{#{NULLISH_COALESCE_LAMBDA_NAME}}}}}{text}{{{{/{NULLISH_COALESCE_LAMBDA_NAME}}}}}"
 
 
 def test_chevron_enabled():
@@ -15,8 +23,29 @@ def test_variable():
     assert render("Hello, {{name}}!", {"name": "world"}) == "Hello, world!"
 
 
-def test_default_variable():
-    template = "Hello, {{#name}}{{.}}{{/name}}{{^name}}world{{/name}}!"
+class TestNullishCoalesce:
+    def test_nullish_coalesce(self):
+        template = f"Hello, {nc('{{name}} ? world')}!"
+
+        assert render(template) == "Hello, world!"
+        assert render(template, {"name": "planet"}) == "Hello, planet!"
+
+    @pytest.mark.parametrize("falsy", [0, 0.0])
+    def test_falsy_values(self, falsy: Any):
+        template = f"Hello, {nc('{{name}} ? world')}!"
+
+        assert render(template, {"name": falsy}) == f"Hello, {falsy}!"
+
+    @pytest.mark.parametrize("nullish", [None, ""])
+    def test_nullish_values(self, nullish: Any):
+        template = f"Hello, {nc('{{name}} ? world')}!"
+
+        assert render(template, {"name": nullish}) == "Hello, world!"
+
+    def test_no_default_value(self):
+        with pytest.raises(ValueError, match="requires a default value"):
+            render(f"Hello, {nc('{{name}}')}!")
 
-    assert render(template, {"name": "planet"}) == "Hello, planet!"
-    assert render(template) == "Hello, world!"
+    def test_multiple_operators(self):
+        with pytest.raises(ValueError, match="must occur only once"):
+            render(f"Hello, {nc('{{name}} ? world ? planet')}!")