No longer silently ignore errors in parametrize callable ids

fogo · fogo · commit cc38ce07eb03 · 2017-01-02T10:55:44.000-02:00
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
@@ -8,6 +8,9 @@ New Features
 * Added an ini option ``doctest_encoding`` to specify which encoding to use for doctest files.
   Thanks `@wheerd`_ for the PR (`#2101`_).
 
+* pytest no longer ignores errors when a callable ids raises in a parametrized
+  test. Thanks `@fogo`_ for the PR.
+
 *
 
 
@@ -39,6 +42,7 @@ Changes
 .. _@fushi: https://github.com/fushi
 .. _@mattduck: https://github.com/mattduck
 .. _@wheerd: https://github.com/wheerd
+.. _@fogo: https://github.com/fogo
 
 .. _#1512: https://github.com/pytest-dev/pytest/issues/1512
 .. _#1874: https://github.com/pytest-dev/pytest/pull/1874
diff --git a/_pytest/python.py b/_pytest/python.py
@@ -928,12 +928,9 @@ def _find_parametrized_scope(argnames, arg2fixturedefs, indirect):
 
 def _idval(val, argname, idx, idfn, config=None):
     if idfn:
-        try:
-            s = idfn(val)
-            if s:
-                return _escape_strings(s)
-        except Exception:
-            pass
+        s = idfn(val)
+        if s:
+            return _escape_strings(s)
 
     if config:
         hook_id = config.hook.pytest_make_parametrize_id(config=config, val=val)
diff --git a/testing/python/metafunc.py b/testing/python/metafunc.py
@@ -297,17 +297,41 @@ def ids(val):
     def test_idmaker_idfn_exception(self):
         from _pytest.python import idmaker
 
+        class BadIdsException(Exception):
+            pass
+
         def ids(val):
-            raise Exception("bad code")
+            raise BadIdsException("ids raised")
 
-        result = idmaker(("a", "b"), [(10.0, IndexError()),
-                                      (20, KeyError()),
-                                      ("three", [1, 2, 3]),
-        ], idfn=ids)
-        assert result == ["10.0-b0",
-                          "20-b1",
-                          "three-b2",
-                         ]
+        with pytest.raises(BadIdsException) as e:
+            idmaker(("a", "b"), [(10.0, IndexError()),
+                                          (20, KeyError()),
+                                          ("three", [1, 2, 3]),
+            ], idfn=ids)
+
+        assert str(e.value) == "ids raised"
+
+    def test_parametrize_ids_exception(self, testdir):
+        """
+        :param testdir: the instance of Testdir class, a temporary
+        test directory.
+        """
+        testdir.makepyfile("""
+                import pytest
+
+                def ids(arg):
+                    raise Exception("bad ids")
+
+                @pytest.mark.parametrize("arg", ["a", "b"], ids=ids)
+                def test_foo(arg):
+                    pass
+            """)
+        result = testdir.runpytest("--collect-only")
+        result.stdout.fnmatch_lines([
+            "*ERROR collecting test_parametrize_ids_exception.py*",
+            "test_parametrize_ids_exception.py:*: in ids",
+            "*raise Exception(\"bad ids\")",
+        ])
 
     def test_idmaker_with_ids(self):
         from _pytest.python import idmaker
