#3724: Custom Jinja2Test for missing site file

esmvaltool/utils/recipe_test_workflow/Jinja2Tests/file_exists.py

@@ -0,0 +1,6 @@
+from pathlib import Path
+
+def file_exists(file_path):
+    run_directory = Path.cwd()
+    site_recipes_file_path = run_directory / file_path
+    return site_recipes_file_path.is_file()

esmvaltool/utils/recipe_test_workflow/flow.cylc

@@ -2,22 +2,28 @@
 {{ assert(SITE != "", "SITE must be set to something other than an empty string") }}
 
 {% set SITE_RECIPES_FILE = "site/" ~ SITE ~ "-recipes.cylc" %}
+{% set MISSING_FILE_MSG =
+    "'" ~ SITE_RECIPES_FILE ~ "' is required for the Recipe Test Workflow and was not "
+    "found - the 'How to add a recipe to the RTW' documentation provides more "
+    "information"%}
+{% set UNDEFINED_VARIABLE_MSG =
+    "variable must be set in your '" ~ SITE_RECIPES_FILE ~ "'- the 'How to add a recipe "
+    "to the RTW' documentation provides more information."%}
 
-# --- Leave a blank line below for a clean error message ---
+# Assert 'site/<site>-recipes.cylc' exists and assert FAST_RECIPES and MEDIUM_RECIPES
+# are imported from it. Produce readable errors if not.
+# --- Text in the three lines above an assert appears in the Jinja2 error ---
 
-# If you see `<-- TemplateNotFound` error below, a `<site>-recipes.cylc` file is missing from the `site` directory.
-# Refer to the the 'How to add a recipe to the RTW' documentation for more information.
-{% include SITE_RECIPES_FILE %}
 
+
+{{ assert(SITE_RECIPES_FILE is file_exists, MISSING_FILE_MSG) }}
 {% from SITE_RECIPES_FILE import FAST_RECIPES, MEDIUM_RECIPES %}
+# --- Text in the three lines above an assert appears in the Jinja2 error ---
+
 
-{% set ERROR_MSG =
-    "is undefined and must be set in '" ~ SITE_RECIPES_FILE ~ "' - the 'How to "
-    "add a recipe to the RTW' documentation provides more information."
-%}
 
-{{ assert(FAST_RECIPES is defined, "FAST_RECIPES " ~ ERROR_MSG)}}
-{{ assert(MEDIUM_RECIPES is defined, "MEDIUM_RECIPES " ~ ERROR_MSG)}}
+{{ assert(FAST_RECIPES is defined, "The FAST_RECIPES " ~ UNDEFINED_VARIABLE_MSG) }}
+{{ assert(MEDIUM_RECIPES is defined, "The MEDIUM_RECIPES " ~ UNDEFINED_VARIABLE_MSG) }}
 
 [scheduler]
     UTC mode = True