allow optional use of filter based on existence

1 files changed, 48 insertions, 0 deletions

diff --git a/tests/test_filters.py b/tests/test_filters.py
index efc82bc..44be6ad 100644
--- a/tests/test_filters.py
+++ b/tests/test_filters.py
@@ -6,7 +6,9 @@ import pytest
 from jinja2 import Environment
 from jinja2 import Markup
 from jinja2 import StrictUndefined
+from jinja2 import TemplateRuntimeError
 from jinja2 import UndefinedError
+from jinja2.exceptions import TemplateAssertionError
 
 
 class Magic:
@@ -774,3 +776,49 @@ class TestFilter:
         t = env.from_string("{{ s|wordwrap(20) }}")
         result = t.render(s="Hello!\nThis is Jinja saying something.")
         assert result == "Hello!\nThis is Jinja saying\nsomething."
+
+    def test_filter_undefined(self, env):
+        with pytest.raises(TemplateAssertionError, match="no filter named 'f'"):
+            env.from_string("{{ var|f }}")
+
+    def test_filter_undefined_in_if(self, env):
+        t = env.from_string("{%- if x is defined -%}{{ x|f }}{%- else -%}x{% endif %}")
+        assert t.render() == "x"
+        with pytest.raises(TemplateRuntimeError, match="no filter named 'f'"):
+            t.render(x=42)
+
+    def test_filter_undefined_in_elif(self, env):
+        t = env.from_string(
+            "{%- if x is defined -%}{{ x }}{%- elif y is defined -%}"
+            "{{ y|f }}{%- else -%}foo{%- endif -%}"
+        )
+        assert t.render() == "foo"
+        with pytest.raises(TemplateRuntimeError, match="no filter named 'f'"):
+            t.render(y=42)
+
+    def test_filter_undefined_in_else(self, env):
+        t = env.from_string(
+            "{%- if x is not defined -%}foo{%- else -%}{{ x|f }}{%- endif -%}"
+        )
+        assert t.render() == "foo"
+        with pytest.raises(TemplateRuntimeError, match="no filter named 'f'"):
+            t.render(x=42)
+
+    def test_filter_undefined_in_nested_if(self, env):
+        t = env.from_string(
+            "{%- if x is not defined -%}foo{%- else -%}{%- if y "
+            "is defined -%}{{ y|f }}{%- endif -%}{{ x }}{%- endif -%}"
+        )
+        assert t.render() == "foo"
+        assert t.render(x=42) == "42"
+        with pytest.raises(TemplateRuntimeError, match="no filter named 'f'"):
+            t.render(x=24, y=42)
+
+    def test_filter_undefined_in_condexpr(self, env):
+        t1 = env.from_string("{{ x|f if x is defined else 'foo' }}")
+        t2 = env.from_string("{{ 'foo' if x is not defined else x|f }}")
+        assert t1.render() == t2.render() == "foo"
+
+        with pytest.raises(TemplateRuntimeError, match="no filter named 'f'"):
+            t1.render(x=42)
+            t2.render(x=42)