Add --no-subtest-reports CLI opt (#199)

Fixes #198.

---------

Signed-off-by: Giampaolo Rodola <g.rodola@gmail.com>
Co-authored-by: Bruno Oliveira <bruno@pytest.org>

Author: giampaolo

CHANGELOG.rst

@@ -1,6 +1,16 @@
 CHANGELOG
 =========
 
+0.14.3 (UNRELEASED)
+-------------------
+
+*XXXX-XX-XX*
+
+* Added experimental ``--no-subtest-reports`` CLI option. This disables
+  subtests output unless it's a failed subtest. (`#198`_)
+
+.. _#198: https://github.com/pytest-dev/pytest-subtests/pull/198
+
 0.14.2
 ------
 

src/pytest_subtests/plugin.py

@@ -46,6 +46,13 @@ def pytest_addoption(parser: pytest.Parser) -> None:
         default=False,
         help="Disables subtest output 'dots' in non-verbose mode (EXPERIMENTAL)",
     )
+    group.addoption(
+        "--no-subtests-reports",
+        action="store_true",
+        dest="no_subtests_reports",
+        default=False,
+        help="Disables subtest output unless it's a failed subtest (EXPERIMENTAL)",
+    )
 
 
 @attr.s
@@ -459,9 +466,12 @@ def pytest_report_teststatus(
 
     outcome = report.outcome
     description = report.sub_test_description()
+    no_output = ("", "", "")
 
     if hasattr(report, "wasxfail"):
-        if outcome == "skipped":
+        if config.option.no_subtests_reports and outcome != "skipped":
+            return no_output
+        elif outcome == "skipped":
             category = "xfailed"
             short = "y"  # x letter is used for regular xfail, y for subtest xfail
             status = "SUBXFAIL"
@@ -476,6 +486,9 @@ def pytest_report_teststatus(
             return None
         short = "" if config.option.no_subtests_shortletter else short
         return f"subtests {category}", short, f"{description} {status}"
+
+    if config.option.no_subtests_reports and outcome != "failed":
+        return no_output
     elif report.passed:
         short = "" if config.option.no_subtests_shortletter else ","
         return f"subtests {outcome}", short, f"{description} SUBPASS"

tests/test_subtests.py

@@ -156,6 +156,62 @@ def test_typing_exported(subtests: SubTests) -> None:
         expected_lines += ["* 1 passed *"]
         result.stdout.fnmatch_lines(expected_lines)
 
+    def test_no_subtests_reports(
+        self, pytester: pytest.Pytester, mode: Literal["normal", "xdist"]
+    ) -> None:
+        pytester.makepyfile(
+            """
+            import pytest
+
+            def test_foo(subtests):
+                for i in range(5):
+                    with subtests.test(msg="custom", i=i):
+                        pass
+        """
+        )
+        # Without `--no-subtests-reports`, subtests are reported normally.
+        result = pytester.runpytest("-v")
+        result.stdout.fnmatch_lines(
+            [
+                "*collected 1 item*",
+                "test_no_subtests_reports.py::test_foo * (i=0) SUBPASS*",
+                "*test_no_subtests_reports.py::test_foo PASSED*",
+                "* 1 passed, 5 subtests passed in*",
+            ]
+        )
+
+        # With `--no-subtests-reports`, passing subtests are no longer reported.
+        result = pytester.runpytest("-v", "--no-subtests-reports")
+        result.stdout.fnmatch_lines(
+            [
+                "*collected 1 item*",
+                "*test_no_subtests_reports.py::test_foo PASSED*",
+                "* 1 passed in*",
+            ]
+        )
+        result.stdout.no_fnmatch_line("*SUBPASS*")
+
+        # Rewrite the test file so the tests fail. Even with the flag, failed subtests are still reported.
+        pytester.makepyfile(
+            """
+            import pytest
+
+            def test_foo(subtests):
+                for i in range(5):
+                    with subtests.test(msg="custom", i=i):
+                        assert False
+        """
+        )
+        result = pytester.runpytest("-v", "--no-subtests-reports")
+        result.stdout.fnmatch_lines(
+            [
+                "*collected 1 item*",
+                "test_no_subtests_reports.py::test_foo * (i=0) SUBFAIL*",
+                "*test_no_subtests_reports.py::test_foo PASSED*",
+                "* 5 failed, 1 passed in*",
+            ]
+        )
+
 
 class TestSubTest:
     """