Clean up messages and add support for loading the old list format

.test_durations

@@ -0,0 +1 @@
+{"tests/test_plugin.py::TestStoreDurations::test_it_stores": 0.08707766099999997, "tests/test_plugin.py::TestStoreDurations::test_it_does_not_store_without_flag": 0.09066593100000003, "tests/test_plugin.py::TestSplitToSuites::test_it_splits[0-1-expected_tests_per_group0]": 0.08363778099999997, "tests/test_plugin.py::TestSplitToSuites::test_it_splits[1-2-expected_tests_per_group1]": 0.12921703699999998, "tests/test_plugin.py::TestSplitToSuites::test_it_splits[2-3-expected_tests_per_group2]": 0.17863698999999988, "tests/test_plugin.py::TestSplitToSuites::test_it_splits[3-4-expected_tests_per_group3]": 0.22171246299999992, "tests/test_plugin.py::TestSplitToSuites::test_it_does_not_split_with_invalid_args": 0.15940266000000003, "tests/test_plugin.py::TestSplitToSuites::test_it_adapts_splits_based_on_new_and_deleted_tests": 0.17758088800000005, "tests/test_plugin.py::TestRaisesUsageErrors::test_returns_nonzero_when_group_but_not_splits": 0.04033764599999978}

src/pytest_split/plugin.py

@@ -1,6 +1,5 @@
 import json
 import os
-from collections import namedtuple
 from typing import TYPE_CHECKING
 
 import pytest
@@ -17,9 +16,6 @@
 # Ugly hack for freezegun compatibility: https://github.com/spulec/freezegun/issues/286
 STORE_DURATIONS_SETUP_AND_TEARDOWN_THRESHOLD = 60 * 10  # seconds
 
-TestGroup = namedtuple("TestGroup", "index, num_tests")
-TestSuite = namedtuple("TestSuite", "splits, num_tests")
-
 
 def pytest_addoption(parser: "Parser") -> None:
     """
@@ -67,7 +63,7 @@ def pytest_cmdline_main(config: "Config") -> "Optional[Union[int, ExitCode]]":
     splits = config.getoption("splits")
 
     if splits is None and group is None:
-        return 0
+        return None
 
     if splits and group is None:
         raise pytest.UsageError("argument `--group` is required")
@@ -98,7 +94,9 @@ def pytest_configure(config: "Config") -> None:
 class Base:
     def __init__(self, config: "Config") -> None:
         """
-        Load cache and configure plugin.
+        Load durations and set up a terminal writer.
+
+        This logic is shared for both the split- and cache plugin.
         """
         self.config = config
         self.writer = create_terminal_writer(self.config)
@@ -109,47 +107,32 @@ def __init__(self, config: "Config") -> None:
         except FileNotFoundError:
             self.cached_durations = {}
 
+        # This code provides backwards compatibility after we switched
+        # from saving durations in a list-of-lists to a dict format
+        # Remove this when bumping to v1
+        if isinstance(self.cached_durations, list):
+            self.cached_durations = {test_name: duration for test_name, duration in self.cached_durations}
+
 
 class PytestSplitPlugin(Base):
     def __init__(self, config: "Config"):
         super().__init__(config)
-        self._suite: TestSuite
-        self._group: TestGroup
+
         self._messages: "List[str]" = []
+
         if not self.cached_durations:
             message = self.writer.markup(
-                "\nNo test durations found. Pytest-split will "
+                "\n[pytest-split] No test durations found. Pytest-split will "
                 "split tests evenly when no durations are found. "
-                "\nYou can expect better results in consequent runs, "
+                "\n[pytest-split] You can expect better results in consequent runs, "
                 "when test timings have been documented.\n"
             )
             self.writer.line(message)
 
-    def pytest_report_collectionfinish(self, config: "Config") -> "List[str]":
-        lines = []
-        if self._messages:
-            lines += self._messages
-
-        if hasattr(self, "_suite"):
-            lines.append(
-                f"Running group {self._group.index}/{self._suite.splits}"
-                f" ({self._group.num_tests}/{self._suite.num_tests}) tests"
-            )
-
-        prefix = "[pytest-split]"
-        lines = [f"{prefix} {m}" for m in lines]
-
-        return lines
-
     @hookimpl(tryfirst=True)
     def pytest_collection_modifyitems(self, config: "Config", items: "List[nodes.Item]") -> None:
         """
-        Instruct Pytest to run the tests we've selected.
-
-        This method is called by Pytest right after Pytest internals finishes
-        collecting tests.
-
-        See https://github.com/pytest-dev/pytest/blob/main/src/_pytest/main.py#L670.
+        Collect and select the tests we want to run, and deselect the rest.
         """
         splits: int = config.option.splits
         group: int = config.option.group
@@ -159,10 +142,7 @@ def pytest_collection_modifyitems(self, config: "Config", items: "List[nodes.Ite
         items[:] = selected_tests
         config.hook.pytest_deselected(items=deselected_tests)
 
-        self._suite = TestSuite(splits, len(items))
-        self._group = TestGroup(group, end_idx - start_idx)
-
-        self.writer.line(self.writer.markup(f"\n\nRunning group {group}/{splits}\n"))
+        self.writer.line(self.writer.markup(f"\n\n[pytest-split] Running group {group}/{splits}\n"))
         return None
 
     @staticmethod
@@ -256,5 +236,7 @@ def pytest_sessionfinish(self) -> None:
         with open(self.config.option.durations_path, "w") as f:
             json.dump(self.cached_durations, f)
 
-        message = self.writer.markup("\n\nStored test durations in {}\n".format(self.config.option.durations_path))
+        message = self.writer.markup(
+            "\n\n[pytest-split] Stored test durations in {}".format(self.config.option.durations_path)
+        )
         self.writer.line(message)

tests/test_plugin.py

@@ -3,6 +3,7 @@
 import os
 
 import pytest
+from _pytest.config import ExitCode
 
 pytest_plugins = ["pytester"]
 
@@ -139,11 +140,11 @@ def test_it_does_not_split_with_invalid_args(self, example_suite, durations_path
 
         # Plugin doesn't run when splits is passed but group is missing
         result = example_suite.inline_run("--splits", "2", "--durations-path", durations_path)  # no --group
-        result.assertoutcome(passed=10)
+        assert result.ret == ExitCode.USAGE_ERROR
 
         # Plugin doesn't run when group is passed but splits is missing
         result = example_suite.inline_run("--group", "2", "--durations-path", durations_path)  # no --splits
-        result.assertoutcome(passed=10)
+        assert result.ret == ExitCode.USAGE_ERROR
 
         # Runs if they both are
         result = example_suite.inline_run("--splits", "2", "--group", "1")
@@ -221,14 +222,6 @@ def test_returns_nonzero_when_splits_below_one(self, example_suite, capsys):
 
 
 class TestHasExpectedOutput:
-    def test_does_not_print_splitting_summary_when_durations_missing(self, example_suite, capsys):
-        result = example_suite.inline_run("--splits", "1", "--group", "1")
-        assert result.ret == 0
-
-        outerr = capsys.readouterr()
-        assert "[pytest-split] Not splitting tests because the durations_report is missing" in outerr.out
-        assert "[pytest-split] Running group" not in outerr.out
-
     def test_prints_splitting_summary_when_durations_present(self, example_suite, capsys, durations_path):
         test_name = "test_prints_splitting_summary_when_durations_present"
         with open(durations_path, "w") as f:
@@ -237,26 +230,7 @@ def test_prints_splitting_summary_when_durations_present(self, example_suite, ca
         assert result.ret == 0
 
         outerr = capsys.readouterr()
-        assert "[pytest-split] Running group 1/1 (10/10) tests" in outerr.out
-
-    def test_prints_splitting_summary_when_storing_durations(self, example_suite, capsys, durations_path):
-        test_name = "test_prints_splitting_summary_when_storing_durations"
-        with open(durations_path, "w") as f:
-            json.dump([[f"{test_name}0/{test_name}.py::test_1", 0.5]], f)
-
-        result = example_suite.inline_run(
-            "--splits",
-            "1",
-            "--group",
-            "1",
-            "--durations-path",
-            durations_path,
-            "--store-durations",
-        )
-        assert result.ret == 0
-
-        outerr = capsys.readouterr()
-        assert "[pytest-split] Not splitting tests because we are storing durations" in outerr.out
+        assert "[pytest-split] Running group 1/1" in outerr.out
 
     def test_does_not_print_splitting_summary_when_no_pytest_split_arguments(self, example_suite, capsys):
         result = example_suite.inline_run()