Suppress a report output when verbosity = 0. (#2774)

* Suppress a report output when verbosity = 0.

* Use os.linesep

docs/changelog/2697.feature.rst

@@ -0,0 +1 @@
+Suppress a report output when verbosity = 0.

src/tox/session/cmd/run/common.py

@@ -165,9 +165,10 @@ def __call__(
         )
 
 
-def report(start: float, runs: list[ToxEnvRunResult], is_colored: bool) -> int:
+def report(start: float, runs: list[ToxEnvRunResult], is_colored: bool, verbosity: int) -> int:
     def _print(color_: int, message: str) -> None:
-        print(f"{color_ if is_colored else ''}{message}{Fore.RESET if is_colored else ''}")
+        if verbosity:
+            print(f"{color_ if is_colored else ''}{message}{Fore.RESET if is_colored else ''}")
 
     successful, skipped = [], []
     for run in runs:
@@ -250,7 +251,12 @@ def execute(state: State, max_workers: int | None, has_spinner: bool, live: bool
         # write the journal
         write_journal(getattr(state.conf.options, "result_json", None), state._journal)
         # report the outcome
-        exit_code = report(state.conf.options.start, ordered_results, state.conf.options.is_colored)
+        exit_code = report(
+            state.conf.options.start,
+            ordered_results,
+            state.conf.options.is_colored,
+            state.conf.options.verbosity,
+        )
         if has_previous:
             signal(SIGINT, previous)
     return exit_code

tests/session/cmd/run/test_common.py

@@ -1,11 +1,13 @@
 from __future__ import annotations
 
+import os
 import re
 from argparse import ArgumentError, ArgumentParser, Namespace
 from pathlib import Path
 
 import pytest
 
+from tox.pytest import ToxProjectCreator
 from tox.session.cmd.run.common import InstallPackageAction, SkipMissingInterpreterAction
 
 
@@ -50,3 +52,11 @@ def test_install_pkg_empty() -> None:
     argument_parser = ArgumentParser()
     with pytest.raises(ArgumentError, match=re.escape("argument --install-pkg: cannot be empty")):
         InstallPackageAction(option_strings=["--install-pkg"], dest="into")(argument_parser, Namespace(), "")
+
+
+def test_empty_report(tox_project: ToxProjectCreator) -> None:
+    proj = tox_project({"tox.ini": ""})
+    outcome = proj.run("exec", "-qq", "--", "python", "-c", "print('foo')")
+
+    outcome.assert_success()
+    outcome.assert_out_err(f"foo{os.linesep}", "")