🧹 Reduce duplication in snippet testing

tests/Tester.py

@@ -1,5 +1,6 @@
 import random
 import textwrap
+from dataclasses import dataclass
 import pickle
 import hashlib
 import hedy
@@ -12,6 +13,7 @@
 import inspect
 import unittest
 import utils
+import typing
 from hedy_content import ALL_KEYWORD_LANGUAGES, KEYWORDS
 
 from hedy_sourcemap import SourceRange
@@ -48,6 +50,52 @@ def __repr__(self):
         return f'Snippet({self.name})'
 
 
+@dataclass
+class YamlSnippet:
+    """A snippet found in one of the YAML files.
+
+    This is a replacement of 'Snippet' with fewer fields, only the fields that
+    are used in the snippet tests.
+
+    `yaml_path` is the path in the YAML where this snippet was found, as an
+    array of either strings or ints.
+
+    For example, in a YAML file that looks like:
+
+    ```
+    adventures:
+        1:
+            code: |
+               print hello
+    ```
+
+    The `yaml_path` would be `['adventures', 1, 'code']`.
+    """
+    filename: str
+    yaml_path: typing.List
+    code: str
+    language: str
+    level: int
+
+    def __post_init__(self):
+        # 'code' may be replaced later on when translating keywords
+        self.original_code = self.code
+        self.name = f'{self.relative_filename}-{self.yaml_path_str}'
+
+    @property
+    def relative_filename(self):
+        return os.path.relpath(self.filename, ROOT_DIR)
+
+    @property
+    def yaml_path_str(self):
+        return '.'.join(str(x) for x in self.yaml_path)
+
+    @property
+    def location(self):
+        """Returns a description of the location."""
+        return f'{self.relative_filename} at {self.yaml_path_str}'
+
+
 class SkippedMapping:
     """ Class used to test if a certain source mapping contains an exception type """
 
@@ -481,6 +529,8 @@ def indent(code, spaces_amount=2, skip_first_line=False):
 
     @staticmethod
     def translate_keywords_in_snippets(snippets):
+        """Mutates the snippets in-place."""
+
         # fill keyword dict for all keyword languages
         keyword_dict = {}
         for lang in ALL_KEYWORD_LANGUAGES:
@@ -495,20 +545,18 @@ def translate_keywords_in_snippets(snippets):
         # NOTE: .format() instead of safe_format() on purpose!
         for snippet in snippets:
             # store original code
-            snippet[1].original_code = snippet[1].code
+            snippet.original_code = snippet.code
             try:
-                if snippet[1].language in ALL_KEYWORD_LANGUAGES.keys():
-                    snippet[1].code = snippet[1].code.format(**keyword_dict[snippet[1].language])
+                if snippet.language in ALL_KEYWORD_LANGUAGES.keys():
+                    snippet.code = snippet.code.format(**keyword_dict[snippet.language])
                 else:
-                    snippet[1].code = snippet[1].code.format(**english_keywords)
+                    snippet.code = snippet.code.format(**english_keywords)
             except KeyError:
                 print("This following snippet contains an invalid placeholder...")
-                print(snippet[1].code)
+                print(snippet.code)
             except ValueError:
                 print("This following snippet contains an unclosed invalid placeholder...")
-                print(snippet[1].code)
-
-        return snippets
+                print(snippet.code)
 
     def format_test_error_md(self, E, snippet: Snippet):
         """Given a snippet and an exception, return a Markdown string describing the problem."""
@@ -538,7 +586,7 @@ def add_arrow(code):
 
         rel_file = os.path.relpath(snippet.filename, ROOT_DIR)
         message.append(f'## {rel_file}')
-        message.append(f'There was a problem in a level {snippet.level} snippet:')
+        message.append(f'There was a problem in a level {snippet.level} snippet, at {snippet.yaml_path_str}:')
 
         # Use a 'caution' admonition because it renders in red
         message.append('> [!CAUTION]')