Merge pull request #6174 from blueyed/ids-iter

parametrized: ids: support generator/iterator

changelog/1857.improvement.rst

@@ -0,0 +1 @@
+``pytest.mark.parametrize`` accepts integers for ``ids`` again, converting it to strings.

changelog/759.improvement.rst

@@ -0,0 +1 @@
+``pytest.mark.parametrize`` supports iterators and generators for ``ids``.

src/_pytest/mark/structures.py

@@ -2,6 +2,8 @@ import inspect
 import warnings
 from collections import namedtuple
 from collections.abc import MutableMapping
+from typing import List
+from typing import Optional
 from typing import Set
 
 import attr
@@ -144,7 +146,15 @@ class Mark:
     #: keyword arguments of the mark decorator
     kwargs = attr.ib()  # Dict[str, object]
 
-    def combined_with(self, other):
+    #: source Mark for ids with parametrize Marks
+    _param_ids_from = attr.ib(type=Optional["Mark"], default=None, repr=False)
+    #: resolved/generated ids with parametrize Marks
+    _param_ids_generated = attr.ib(type=Optional[List[str]], default=None, repr=False)
+
+    def _has_param_ids(self):
+        return "ids" in self.kwargs or len(self.args) >= 4
+
+    def combined_with(self, other: "Mark") -> "Mark":
         """
         :param other: the mark to combine with
         :type other: Mark
@@ -153,8 +163,20 @@ class Mark:
         combines by appending args and merging the mappings
         """
         assert self.name == other.name
+
+        # Remember source of ids with parametrize Marks.
+        param_ids_from = None  # type: Optional[Mark]
+        if self.name == "parametrize":
+            if other._has_param_ids():
+                param_ids_from = other
+            elif self._has_param_ids():
+                param_ids_from = self
+
         return Mark(
-            self.name, self.args + other.args, dict(self.kwargs, **other.kwargs)
+            self.name,
+            self.args + other.args,
+            dict(self.kwargs, **other.kwargs),
+            param_ids_from=param_ids_from,
         )
 
 

src/_pytest/python.py

@@ -10,6 +10,7 @@ from collections.abc import Sequence
 from functools import partial
 from textwrap import dedent
 from typing import List
+from typing import Optional
 from typing import Tuple
 
 import py
@@ -36,6 +37,7 @@ from _pytest.deprecated import FUNCARGNAMES
 from _pytest.main import FSHookProxy
 from _pytest.mark import MARK_GEN
 from _pytest.mark.structures import get_unpacked_marks
+from _pytest.mark.structures import Mark
 from _pytest.mark.structures import normalize_mark_list
 from _pytest.outcomes import fail
 from _pytest.outcomes import skip
@@ -122,7 +124,7 @@ def pytest_cmdline_main(config):
 
 def pytest_generate_tests(metafunc):
     for marker in metafunc.definition.iter_markers(name="parametrize"):
-        metafunc.parametrize(*marker.args, **marker.kwargs)
+        metafunc.parametrize(*marker.args, **marker.kwargs, _param_mark=marker)
 
 
 def pytest_configure(config):
@@ -914,7 +916,16 @@ class Metafunc:
         warnings.warn(FUNCARGNAMES, stacklevel=2)
         return self.fixturenames
 
-    def parametrize(self, argnames, argvalues, indirect=False, ids=None, scope=None):
+    def parametrize(
+        self,
+        argnames,
+        argvalues,
+        indirect=False,
+        ids=None,
+        scope=None,
+        *,
+        _param_mark: Optional[Mark] = None
+    ):
         """ Add new invocations to the underlying test function using the list
         of argvalues for the given argnames.  Parametrization is performed
         during the collection phase.  If you need to setup expensive resources
@@ -937,13 +948,22 @@ class Metafunc:
             function so that it can perform more expensive setups during the
             setup phase of a test rather than at collection time.
 
-        :arg ids: list of string ids, or a callable.
+        :arg ids: sequence of (or generator for) ids for ``argvalues``,
-            If strings, each is corresponding to the argvalues so that they are
+              or a callable to return part of the id for each argvalue.
-            part of the test id. If None is given as id of specific test, the
+
-            automatically generated id for that argument will be used.
+            With sequences (and generators like ``itertools.count()``) the
-            If callable, it should take one argument (a single argvalue) and return
+            returned ids should be of type ``string``, ``int``, ``float``,
-            a string or return None. If None, the automatically generated id for that
+            ``bool``, or ``None``.
-            argument will be used.
+            They are mapped to the corresponding index in ``argvalues``.
+            ``None`` means to use the auto-generated id.
+
+            If it is a callable it will be called for each entry in
+            ``argvalues``, and the return value is used as part of the
+            auto-generated id for the whole set (where parts are joined with
+            dashes ("-")).
+            This is useful to provide more specific ids for certain items, e.g.
+            dates.  Returning ``None`` will use an auto-generated id.
+
             If no ids are provided they will be generated automatically from
             the argvalues.
 
@@ -977,8 +997,18 @@ class Metafunc:
 
         arg_values_types = self._resolve_arg_value_types(argnames, indirect)
 
+        # Use any already (possibly) generated ids with parametrize Marks.
+        if _param_mark and _param_mark._param_ids_from:
+            generated_ids = _param_mark._param_ids_from._param_ids_generated
+            if generated_ids is not None:
+                ids = generated_ids
+
         ids = self._resolve_arg_ids(argnames, ids, parameters, item=self.definition)
 
+        # Store used (possibly generated) ids with parametrize Marks.
+        if _param_mark and _param_mark._param_ids_from and generated_ids is None:
+            object.__setattr__(_param_mark._param_ids_from, "_param_ids_generated", ids)
+
         scopenum = scope2index(
             scope, descr="parametrize() call in {}".format(self.function.__name__)
         )
@@ -1013,27 +1043,48 @@ class Metafunc:
         :rtype: List[str]
         :return: the list of ids for each argname given
         """
-        from _pytest._io.saferepr import saferepr
-
         idfn = None
         if callable(ids):
             idfn = ids
             ids = None
         if ids:
             func_name = self.function.__name__
-            if len(ids) != len(parameters):
+            ids = self._validate_ids(ids, parameters, func_name)
-                msg = "In {}: {} parameter sets specified, with different number of ids: {}"
-                fail(msg.format(func_name, len(parameters), len(ids)), pytrace=False)
-            for id_value in ids:
-                if id_value is not None and not isinstance(id_value, str):
-                    msg = "In {}: ids must be list of strings, found: {} (type: {!r})"
-                    fail(
-                        msg.format(func_name, saferepr(id_value), type(id_value)),
-                        pytrace=False,
-                    )
         ids = idmaker(argnames, parameters, idfn, ids, self.config, item=item)
         return ids
 
+    def _validate_ids(self, ids, parameters, func_name):
+        try:
+            len(ids)
+        except TypeError:
+            try:
+                it = iter(ids)
+            except TypeError:
+                raise TypeError("ids must be a callable, sequence or generator")
+            else:
+                import itertools
+
+                new_ids = list(itertools.islice(it, len(parameters)))
+        else:
+            new_ids = list(ids)
+
+        if len(new_ids) != len(parameters):
+            msg = "In {}: {} parameter sets specified, with different number of ids: {}"
+            fail(msg.format(func_name, len(parameters), len(ids)), pytrace=False)
+        for idx, id_value in enumerate(new_ids):
+            if id_value is not None:
+                if isinstance(id_value, (float, int, bool)):
+                    new_ids[idx] = str(id_value)
+                elif not isinstance(id_value, str):
+                    from _pytest._io.saferepr import saferepr
+
+                    msg = "In {}: ids must be list of string/float/int/bool, found: {} (type: {!r}) at index {}"
+                    fail(
+                        msg.format(func_name, saferepr(id_value), type(id_value), idx),
+                        pytrace=False,
+                    )
+        return new_ids
+
     def _resolve_arg_value_types(self, argnames, indirect):
         """Resolves if each parametrized argument must be considered a parameter to a fixture or a "funcarg"
         to the function, based on the ``indirect`` parameter of the parametrized() call.

testing/python/metafunc.py

@@ -9,6 +9,7 @@ from hypothesis import strategies
 import pytest
 from _pytest import fixtures
 from _pytest import python
+from _pytest.outcomes import fail
 from _pytest.python import _idval
 
 
@@ -62,6 +63,39 @@ class TestMetafunc:
         pytest.raises(ValueError, lambda: metafunc.parametrize("y", [5, 6]))
         pytest.raises(ValueError, lambda: metafunc.parametrize("y", [5, 6]))
 
+        with pytest.raises(
+            TypeError, match="^ids must be a callable, sequence or generator$"
+        ):
+            metafunc.parametrize("y", [5, 6], ids=42)
+
+    def test_parametrize_error_iterator(self):
+        def func(x):
+            raise NotImplementedError()
+
+        class Exc(Exception):
+            def __repr__(self):
+                return "Exc(from_gen)"
+
+        def gen():
+            yield 0
+            yield None
+            yield Exc()
+
+        metafunc = self.Metafunc(func)
+        metafunc.parametrize("x", [1, 2], ids=gen())
+        assert [(x.funcargs, x.id) for x in metafunc._calls] == [
+            ({"x": 1}, "0"),
+            ({"x": 2}, "2"),
+        ]
+        with pytest.raises(
+            fail.Exception,
+            match=(
+                r"In func: ids must be list of string/float/int/bool, found:"
+                r" Exc\(from_gen\) \(type: <class .*Exc'>\) at index 2"
+            ),
+        ):
+            metafunc.parametrize("x", [1, 2, 3], ids=gen())
+
     def test_parametrize_bad_scope(self, testdir):
         def func(x):
             pass
@@ -168,6 +202,26 @@ class TestMetafunc:
                 ("x", "y"), [("abc", "def"), ("ghi", "jkl")], ids=["one"]
             )
 
+    def test_parametrize_ids_iterator_without_mark(self):
+        import itertools
+
+        def func(x, y):
+            pass
+
+        it = itertools.count()
+
+        metafunc = self.Metafunc(func)
+        metafunc.parametrize("x", [1, 2], ids=it)
+        metafunc.parametrize("y", [3, 4], ids=it)
+        ids = [x.id for x in metafunc._calls]
+        assert ids == ["0-2", "0-3", "1-2", "1-3"]
+
+        metafunc = self.Metafunc(func)
+        metafunc.parametrize("x", [1, 2], ids=it)
+        metafunc.parametrize("y", [3, 4], ids=it)
+        ids = [x.id for x in metafunc._calls]
+        assert ids == ["4-6", "4-7", "5-6", "5-7"]
+
     def test_parametrize_empty_list(self):
         """#510"""
 
@@ -527,9 +581,22 @@ class TestMetafunc:
             @pytest.mark.parametrize("arg", ({1: 2}, {3, 4}), ids=ids)
             def test(arg):
                 assert arg
+
+            @pytest.mark.parametrize("arg", (1, 2.0, True), ids=ids)
+            def test_int(arg):
+                assert arg
             """
         )
-        assert testdir.runpytest().ret == 0
+        result = testdir.runpytest("-vv", "-s")
+        result.stdout.fnmatch_lines(
+            [
+                "test_parametrize_ids_returns_non_string.py::test[arg0] PASSED",
+                "test_parametrize_ids_returns_non_string.py::test[arg1] PASSED",
+                "test_parametrize_ids_returns_non_string.py::test_int[1] PASSED",
+                "test_parametrize_ids_returns_non_string.py::test_int[2.0] PASSED",
+                "test_parametrize_ids_returns_non_string.py::test_int[True] PASSED",
+            ]
+        )
 
     def test_idmaker_with_ids(self):
         from _pytest.python import idmaker
@@ -1179,12 +1246,12 @@ class TestMetafuncFunctional:
         result.stdout.fnmatch_lines(["* 1 skipped *"])
 
     def test_parametrized_ids_invalid_type(self, testdir):
-        """Tests parametrized with ids as non-strings (#1857)."""
+        """Test error with non-strings/non-ints, without generator (#1857)."""
         testdir.makepyfile(
             """
             import pytest
 
-            @pytest.mark.parametrize("x, expected", [(10, 20), (40, 80)], ids=(None, 2))
+            @pytest.mark.parametrize("x, expected", [(1, 2), (3, 4), (5, 6)], ids=(None, 2, type))
             def test_ids_numbers(x,expected):
                 assert x * 2 == expected
         """
@@ -1192,7 +1259,8 @@ class TestMetafuncFunctional:
         result = testdir.runpytest()
         result.stdout.fnmatch_lines(
             [
-                "*In test_ids_numbers: ids must be list of strings, found: 2 (type: *'int'>)*"
+                "In test_ids_numbers: ids must be list of string/float/int/bool,"
+                " found: <class 'type'> (type: <class 'type'>) at index 2"
             ]
         )
 
@@ -1773,3 +1841,39 @@ class TestMarkersWithParametrization:
         )
         result = testdir.runpytest()
         result.assert_outcomes(passed=1)
+
+    def test_parametrize_iterator(self, testdir):
+        testdir.makepyfile(
+            """
+            import itertools
+            import pytest
+
+            id_parametrize = pytest.mark.parametrize(
+                ids=("param%d" % i for i in itertools.count())
+            )
+
+            @id_parametrize('y', ['a', 'b'])
+            def test1(y):
+                pass
+
+            @id_parametrize('y', ['a', 'b'])
+            def test2(y):
+                pass
+
+            @pytest.mark.parametrize("a, b", [(1, 2), (3, 4)], ids=itertools.count())
+            def test_converted_to_str(a, b):
+                pass
+        """
+        )
+        result = testdir.runpytest("-vv", "-s")
+        result.stdout.fnmatch_lines(
+            [
+                "test_parametrize_iterator.py::test1[param0] PASSED",
+                "test_parametrize_iterator.py::test1[param1] PASSED",
+                "test_parametrize_iterator.py::test2[param0] PASSED",
+                "test_parametrize_iterator.py::test2[param1] PASSED",
+                "test_parametrize_iterator.py::test_converted_to_str[0] PASSED",
+                "test_parametrize_iterator.py::test_converted_to_str[1] PASSED",
+                "*= 6 passed in *",
+            ]
+        )