Added error handling instruction append, added additional test cases, corrected JinJa2 template, and regenerated test cases.

Author: BethanyG

exercises/practice/minesweeper/.docs/instructions.append.md

@@ -1,4 +1,14 @@
-# Implementation Notes
-The board function must validate its input and raise a
-ValueError with a *meaningful* error message if the
-input turns out to be malformed.
+# Instructions append
+
+## Exception messages
+
+Sometimes it is necessary to [raise an exception](https://docs.python.org/3/tutorial/errors.html#raising-exceptions). When you do this, you should always include a **meaningful error message** to indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. For situations where you know that the error source will be a certain type, you can choose to raise one of the [built in error types](https://docs.python.org/3/library/exceptions.html#base-classes), but should still include a meaningful message.
+
+This particular exercise requires that you use the [raise statement](https://docs.python.org/3/reference/simple_stmts.html#the-raise-statement) to "throw" a `ValueError` when the `board()` function receives malformed input. The tests will only pass if you both `raise` the `exception` and include a message with it.
+
+To raise a `ValueError` with a message, write the message as an argument to the `exception` type:
+
+```python
+# when the board receives malformed input
+raise ValueError("The board is invalid with current input.")
+```

exercises/practice/minesweeper/.meta/additional_tests.json

@@ -38,15 +38,15 @@
           "  "
 	      ]
       },
-      "expected": {"error": "The minefield must have a consistent length"}
+      "expected": {"error": "The board is invalid with current input."}
     },
     {
       "description": "invalid char",
       "property": "annotate",
       "input": {
         "minefield": ["X  * "]
       },
-      "expected": {"error": "The minefield contains an invalid character"}
+      "expected": {"error": "The board is invalid with current input."}
 
     }
   ]

exercises/practice/minesweeper/.meta/example.py

@@ -1,5 +1,5 @@
 def annotate(minefield):
-    if(minefield == []):
+    if not minefield:
         return []
     verify_board(minefield)
     row_len = len(minefield[0])
@@ -30,11 +30,11 @@ def verify_board(minefield):
     # Rows with different lengths
     row_len = len(minefield[0])
     if not all(len(row) == row_len for row in minefield):
-        raise ValueError("Invalid board")
+        raise ValueError("The board is invalid with current input.")
 
     # Unknown character in board
     character_set = set()
     for row in minefield:
         character_set.update(row)
     if character_set - set(' *'):
-        raise ValueError("Invalid board")
+        raise ValueError("The board is invalid with current input.")

exercises/practice/minesweeper/.meta/template.j2

@@ -14,10 +14,11 @@ class {{ exercise | camel_case }}Test(unittest.TestCase):
     {% for case in additional_cases -%}
     def test_{{ case["description"] | to_snake }}(self):
         {%- if case is error_case %}
-        with self.assertRaisesWithMessage(ValueError):
+        with self.assertRaises(ValueError) as err:
             {{ test_call(case) }}
+        self.assertEqual(type(err.exception), ValueError)
+        self.assertEqual(err.exception.args[0], "{{ case["expected"]["error"] }}")
         {%- else %}
         self.assertEqual({{- test_call(case) }}, {{ case["expected"] }})
         {%- endif %}
     {% endfor %}
-{{ macros.footer(True) }}

exercises/practice/minesweeper/minesweeper_test.py

@@ -58,17 +58,17 @@ def test_annotate_9(self):
         )
 
     def test_different_len(self):
-        with self.assertRaisesWithMessage(ValueError):
+        with self.assertRaises(ValueError) as err:
             annotate([" ", "*  ", "  "])
+        self.assertEqual(type(err.exception), ValueError)
+        self.assertEqual(
+            err.exception.args[0], "The board is invalid with current input."
+        )
 
     def test_invalid_char(self):
-        with self.assertRaisesWithMessage(ValueError):
+        with self.assertRaises(ValueError) as err:
             annotate(["X  * "])
-
-    # Utility functions
-    def assertRaisesWithMessage(self, exception):
-        return self.assertRaisesRegex(exception, r".+")
-
-
-if __name__ == "__main__":
-    unittest.main()
+        self.assertEqual(type(err.exception), ValueError)
+        self.assertEqual(
+            err.exception.args[0], "The board is invalid with current input."
+        )