pytester: quick fix error introduced in #5990

- added a test to check this condition

Signed-off-by: Alexandre Mulatinho <alex@mulatinho.net>

changelog/6532.bugfix.rst

@@ -0,0 +1 @@
+Fix problem with ``testdir`` not recognizing errors correctly in runs with a single test.

src/_pytest/pytester.py

@@ -456,7 +456,7 @@ class RunResult:
             "passed": d.get("passed", 0),
             "skipped": d.get("skipped", 0),
             "failed": d.get("failed", 0),
-            "error": d.get("error", 0),
+            "error": d.get("error", 0) + d.get("errors", 0),
             "xpassed": d.get("xpassed", 0),
             "xfailed": d.get("xfailed", 0),
         }

testing/test_pytester.py

@@ -682,3 +682,23 @@ def test_run_result_repr():
         repr(r) == "<RunResult ret=99 len(stdout.lines)=3"
         " len(stderr.lines)=4 duration=0.50s>"
     )
+
+
+def test_run_pytester_with_single_test(testdir):
+    testcode = """
+        import pytest
+
+        @pytest.fixture
+        def bad_fixture():
+            raise Exception("bad")
+
+        def test_error1(bad_fixture):
+            pass
+
+        def test_error2(bad_fixture):
+            pass
+    """
+
+    testdir.makepyfile(testcode)
+    result = testdir.runpytest()
+    result.assert_outcomes(error=2)