making use of the expected property of RuleTest

Author: forman

tests/test_testing.py

@@ -65,25 +65,47 @@ def test_raises_invalid_with_count(self):
         with pytest.raises(
             AssertionError,
             match=(
-                "Rule 'force-title': test_invalid_1:"
+                "Rule 'force-title': test_invalid_0:"
                 " expected one problem, but got no problems."
             ),
         ):
             tester.run(
                 "force-title",
                 ForceTitle,
                 invalid=[
-                    RuleTest(dataset=INVALID_DATASET_1, expected=1),
                     RuleTest(dataset=VALID_DATASET_1, expected=1),
                 ],
             )
 
-    def test_raises_invalid_with_message(self):
+    def test_raises_valid_with_count(self):
         tester = RuleTester(rules={"testing/force-title": "error"})
         with pytest.raises(
             AssertionError,
             match=(
-                "Rule 'force-title': test_invalid_1:"
+                "Rule 'force-title':"
+                " test_invalid_raises_valid_with_count:"
+                " expected one problem, but got no problems."
+            ),
+        ):
+            tester.run(
+                "force-title",
+                ForceTitle,
+                invalid=[
+                    RuleTest(
+                        dataset=VALID_DATASET_1,
+                        expected=1,
+                        name="raises_valid_with_count",
+                    ),
+                ],
+            )
+
+    def test_raises_invalid_with_matching_message(self):
+        tester = RuleTester(rules={"testing/force-title": "error"})
+        with pytest.raises(
+            AssertionError,
+            match=(
+                "Rule 'force-title':"
+                " test_invalid_raises_invalid_with_matching_message:"
                 " expected one problem, but got no problems:\n"
                 "Expected message:\n"
                 "  0: Datasets must have a title"
@@ -94,11 +116,34 @@ def test_raises_invalid_with_message(self):
                 ForceTitle,
                 invalid=[
                     RuleTest(
-                        dataset=INVALID_DATASET_1,
+                        dataset=VALID_DATASET_1,
                         expected=["Datasets must have a title"],
+                        name="raises_invalid_with_matching_message",
                     ),
+                ],
+            )
+
+    def test_raises_invalid_with_mismatching_message(self):
+        tester = RuleTester(rules={"testing/force-title": "error"})
+        with pytest.raises(
+            AssertionError,
+            match=(
+                "Rule 'force-title':"
+                " test_invalid_raises_invalid_with_mismatching_message:"
+                " got one error as expected, but encountered message mismatch:\n"
+                "Message 0:\n"
+                "  Expected: Batasets bust bave a bitle\n"
+                "  Actual: Datasets must have a title"
+            ),
+        ):
+            tester.run(
+                "force-title",
+                ForceTitle,
+                invalid=[
                     RuleTest(
-                        dataset=VALID_DATASET_1, expected=["Datasets must have a title"]
+                        dataset=INVALID_DATASET_1,
+                        expected=["Batasets bust bave a bitle"],
+                        name="raises_invalid_with_mismatching_message",
                     ),
                 ],
             )

xrlint/testing.py

@@ -222,6 +222,7 @@ def _test_rule(
                     lines.append(f"  Actual: {result_text}")
             if all_ok:
                 return None
+
         else:
             if expected_messages:
                 lines.append(
@@ -234,14 +235,18 @@ def _test_rule(
                 for i, text in enumerate(map(_get_message_text, result.messages)):
                     lines.append(f"  {i}: {text}")
 
-        actual = format_problems(result.error_count, result.warning_count)
-        expected = format_count(expected_message_count, "problem")
-        messages = "\n".join(lines)
-        messages = (":\n" + messages) if messages else "."
-        return (
-            f"Rule {rule_name!r}: {test_id}:"
-            f" expected {expected}, but got {actual}{messages}"
-        )
+        result_text = format_problems(result.error_count, result.warning_count)
+        if expected_message_count == result_message_count:
+            problem_text = (
+                f"got {result_text} as expected, but encountered message mismatch"
+            )
+        else:
+            expected_text = format_count(expected_message_count, "problem")
+            problem_text = f"expected {expected_text}, but got {result_text}"
+
+        messages_text = "\n".join(lines)
+        messages_text = (":\n" + messages_text) if messages_text else "."
+        return f"Rule {rule_name!r}: {test_id}: {problem_text}{messages_text}"
 
 
 def _format_test_id(