feat: add option to truncate GitHub annotations

README.md

@@ -36,6 +36,8 @@ If your test is running in a Docker container, you have to install this plugin a
 
 If your tests are run from a subdirectory of the git repository, you have to set the `PYTEST_RUN_PATH` environment variable to the path of that directory relative to the repository root in order for GitHub to identify the files with errors correctly.
 
+To keep GitHub Actions annotations concise, pass `--github-annotation-max-length=N` to truncate annotation messages longer than `N` characters. The default value is `0`, which disables truncation.
+
 ### Warning annotations
 
 This plugin also supports warning annotations when used with Pytest 6.0+. To disable warning annotations, pass `--exclude-warning-annotations` to pytest.

plugin_test.py

@@ -4,13 +4,18 @@
 import sys
 import warnings
 from collections import Counter
+from pathlib import Path
 
 import pytest
 from packaging import version
 
-from pytest_github_actions_annotate_failures.plugin import _AnnotateWarnings
+from pytest_github_actions_annotate_failures.plugin import (
+    _AnnotateWarnings,
+    _truncate_message,
+)
 
 PYTEST_VERSION = version.parse(pytest.__version__)
+REPO_ROOT = Path(__file__).parent
 pytest_plugins = "pytester"
 
 
@@ -393,6 +398,55 @@ def test_fail():
     result.stderr.no_fnmatch_line("::*assert x += 1*")
 
 
+def test_truncate_message():
+    assert _truncate_message("abc", 0) == "abc"
+    assert _truncate_message("abc", 3) == "abc"
+    assert _truncate_message("abcdef", 5) == "ab..."
+    assert _truncate_message("abcdef", 2) == ".."
+
+
+def test_annotation_fail_with_max_length(
+    pytester: pytest.Pytester,
+    monkeypatch: pytest.MonkeyPatch,
+):
+    pytester.makepyfile(
+        """
+        import pytest
+
+        def test_fail():
+            assert False, "x" * 1000
+        """
+    )
+    monkeypatch.setenv("GITHUB_ACTIONS", "true")
+    monkeypatch.setenv("PYTHONPATH", str(REPO_ROOT))
+    result = pytester.runpytest_subprocess(
+        "-p",
+        "pytest_github_actions_annotate_failures.plugin",
+        "--github-annotation-max-length=80",
+    )
+    lines = [line for line in result.errlines if line.startswith("::error ")]
+
+    assert len(lines) == 1
+    annotation_message = lines[0].split("::", 2)[2].replace("%0A", "\n")
+    assert len(annotation_message) == 80
+    assert annotation_message.endswith("...")
+    assert "x" * 100 not in annotation_message
+
+
+def test_annotation_max_length_rejects_negative(
+    pytester: pytest.Pytester, monkeypatch: pytest.MonkeyPatch
+):
+    monkeypatch.setenv("PYTHONPATH", str(REPO_ROOT))
+    result = pytester.runpytest_subprocess(
+        "-p",
+        "pytest_github_actions_annotate_failures.plugin",
+        "--github-annotation-max-length=-1",
+    )
+    result.stderr.fnmatch_lines(
+        ["ERROR: --github-annotation-max-length must be greater than or equal to 0"]
+    )
+
+
 def test_class_method(pytester: pytest.Pytester, monkeypatch: pytest.MonkeyPatch):
     pytester.makepyfile(
         """

pytest_github_actions_annotate_failures/plugin.py

@@ -13,6 +13,8 @@
 
     from _pytest.reports import TestReport
 
+_ELLIPSIS = "..."
+
 
 # Reference:
 # https://docs.pytest.org/en/latest/writing_plugins.html#hookwrapper-executing-around-other-hooks
@@ -24,6 +26,9 @@
 
 
 class _AnnotateErrors:
+    def __init__(self, max_annotation_length: int = 0) -> None:
+        self.max_annotation_length = max_annotation_length
+
     @pytest.hookimpl(tryfirst=True)
     def pytest_runtest_logreport(self, report: TestReport):
         """Handle test reporting for all pytest versions."""
@@ -68,7 +73,7 @@ def pytest_runtest_logreport(self, report: TestReport):
                 "error",
                 compute_path(filesystempath),
                 lineno,
-                message=longrepr,
+                message=_truncate_message(longrepr, self.max_annotation_length),
             )
             print(workflow_command, file=sys.stderr)
 
@@ -96,6 +101,9 @@ def compute_path(filesystempath: str) -> str:
 
 
 class _AnnotateWarnings:
+    def __init__(self, max_annotation_length: int = 0) -> None:
+        self.max_annotation_length = max_annotation_length
+
     def pytest_warning_recorded(
         self,
         warning_message: WarningMessage,
@@ -116,7 +124,9 @@ def pytest_warning_recorded(
             "warning",
             compute_path(filesystempath),
             warning_message.lineno,
-            message=str(warning_message.message),
+            message=_truncate_message(
+                str(warning_message.message), self.max_annotation_length
+            ),
         )
         print(workflow_command, file=sys.stderr)
 
@@ -129,6 +139,16 @@ def pytest_addoption(parser):
         default=False,
         help="Exclude annotating warnings in GitHub Actions.",
     )
+    group.addoption(
+        "--github-annotation-max-length",
+        action="store",
+        default=0,
+        type=int,
+        help=(
+            "Maximum length of GitHub Actions annotation messages. "
+            "Use 0 to disable truncation."
+        ),
+    )
 
 
 def pytest_configure(config):
@@ -138,10 +158,19 @@ def pytest_configure(config):
     if config.pluginmanager.hasplugin("xdist") and hasattr(config, "workerinput"):
         return
 
+    max_annotation_length = config.option.github_annotation_max_length
+    if max_annotation_length < 0:
+        msg = "--github-annotation-max-length must be greater than or equal to 0"
+        raise pytest.UsageError(msg)
+
     if not config.option.exclude_warning_annotations:
-        config.pluginmanager.register(_AnnotateWarnings(), "annotate_warnings")
+        config.pluginmanager.register(
+            _AnnotateWarnings(max_annotation_length), "annotate_warnings"
+        )
 
-    config.pluginmanager.register(_AnnotateErrors(), "annotate_errors")
+    config.pluginmanager.register(
+        _AnnotateErrors(max_annotation_length), "annotate_errors"
+    )
 
 
 def _build_workflow_command(
@@ -176,3 +205,13 @@ def _build_workflow_command(
 
 def _escape(s: str) -> str:
     return s.replace("%", "%25").replace("\r", "%0D").replace("\n", "%0A")
+
+
+def _truncate_message(message: str, max_length: int) -> str:
+    if max_length <= 0 or len(message) <= max_length:
+        return message
+
+    if max_length <= len(_ELLIPSIS):
+        return _ELLIPSIS[:max_length]
+
+    return message[: max_length - len(_ELLIPSIS)] + _ELLIPSIS