fix: Allow subtests to xfail

This change ensures that all `makereport` hooks get called prior to
subtests transforming the constructed `TestReport` to a `SubTestReport`.
A test is added for pytest style usage and an xfailing test is added for
unittest style since the same issue affecting skip counting is present
for xfail counting.

Fixes #24

pytest_subtests.py

@@ -71,14 +71,19 @@ def _from_json(cls, reportdict):
         )
         return report
 
+    @classmethod
+    def from_test_report(cls, test_report):
+        return super()._from_json(test_report._to_json())
+
 
 def _addSubTest(self, test_case, test, exc_info):
     if exc_info is not None:
         msg = test._message if isinstance(test._message, str) else None
         call_info = make_call_info(
             ExceptionInfo(exc_info), start=0, stop=0, duration=0, when="call"
         )
-        sub_report = SubTestReport.from_item_and_call(item=self, call=call_info)
+        report = self.ihook.pytest_runtest_makereport(item=self, call=call_info)
+        sub_report = SubTestReport.from_test_report(report)
         sub_report.context = SubTestContext(msg, dict(test.params))
         self.ihook.pytest_runtest_logreport(report=sub_report)
         if check_interactive_exception(call_info, sub_report):
@@ -171,7 +176,8 @@ def test(self, msg=None, **kwargs):
         call_info = make_call_info(
             exc_info, start=start, stop=stop, duration=duration, when="call"
         )
-        sub_report = SubTestReport.from_item_and_call(item=self.item, call=call_info)
+        report = self.ihook.pytest_runtest_makereport(item=self.item, call=call_info)
+        sub_report = SubTestReport.from_test_report(report)
         sub_report.context = SubTestContext(msg, kwargs.copy())
 
         captured.update_report(sub_report)

tests/test_subtests.py

@@ -103,6 +103,27 @@ def test_foo(subtests):
         expected_lines += ["* 1 passed, 3 skipped in *"]
         result.stdout.fnmatch_lines(expected_lines)
 
+    def test_xfail(self, testdir, mode):
+        testdir.makepyfile(
+            """
+            import pytest
+            def test_foo(subtests):
+                for i in range(5):
+                    with subtests.test(msg="custom", i=i):
+                        if i % 2 == 0:
+                            pytest.xfail('even number')
+        """
+        )
+        if mode == "normal":
+            result = testdir.runpytest()
+            expected_lines = ["collected 1 item"]
+        else:
+            pytest.importorskip("xdist")
+            result = testdir.runpytest("-n1")
+            expected_lines = ["gw0 [1]"]
+        expected_lines += ["* 1 passed, 3 xfailed in *"]
+        result.stdout.fnmatch_lines(expected_lines)
+
 
 class TestSubTest:
     """
@@ -234,6 +255,35 @@ def test_foo(self):
                 ["collected 1 item", "* 3 skipped, 1 passed in *"]
             )
 
+    @pytest.mark.parametrize("runner", ["unittest", "pytest-normal", "pytest-xdist"])
+    @pytest.mark.xfail(reason="Not producing the expected results (#5)")
+    def test_xfail(self, testdir, runner):
+        p = testdir.makepyfile(
+            """
+            import pytest
+            from unittest import expectedFailure, TestCase, main
+
+            class T(TestCase):
+                @expectedFailure
+                def test_foo(self):
+                    for i in range(5):
+                        with self.subTest(msg="custom", i=i):
+                            if i % 2 == 0:
+                                raise pytest.xfail('even number')
+
+            if __name__ == '__main__':
+                main()
+        """
+        )
+        if runner == "unittest":
+            result = testdir.runpython(p)
+            result.stderr.fnmatch_lines(["Ran 1 test in *", "OK (expected failures=3)"])
+        else:
+            result = testdir.runpytest(p)
+            result.stdout.fnmatch_lines(
+                ["collected 1 item", "* 3 xfailed, 1 passed in *"]
+            )
+
 
 class TestCapture:
     def create_file(self, testdir):