tests: Skip snapshot tests if Textual is outdated

requirements-test.txt

@@ -8,3 +8,4 @@ setuptools; python_version >= '3.12'
 pkgconfig
 pytest-textual-snapshot
 textual >= 0.43, != 0.65.2, != 0.66
+packaging

setup.py

@@ -120,6 +120,7 @@ def build_js_files(self):
     "setuptools; python_version >= '3.12'",
     "pytest-textual-snapshot",
     "textual >= 0.43, != 0.65.2, != 0.66",
+    "packaging",
 ]
 
 benchmark_requires = [

tests/conftest.py

@@ -2,6 +2,12 @@
 import sys
 
 import pytest
+from packaging import version
+
+SNAPSHOT_MINIMUM_VERSIONS = {
+    "textual": "0.73",
+    "pytest-textual-snapshot": "1.0",
+}
 
 
 @pytest.fixture
@@ -13,7 +19,48 @@ def free_port():
     return port_number
 
 
-if sys.version_info < (3, 8):
-    # Ignore unused Textual snapshots on Python 3.7
-    def pytest_configure(config):
+def _snapshot_skip_reason():
+    if sys.version_info < (3, 8):
+        # Every version available for 3.7 is too old
+        return f"snapshot tests require textual>={SNAPSHOT_MINIMUM_VERSIONS['textual']}"
+
+    from importlib import metadata  # Added in 3.8
+
+    for lib, min_ver in SNAPSHOT_MINIMUM_VERSIONS.items():
+        try:
+            ver = version.parse(metadata.version(lib))
+        except ImportError:
+            return f"snapshot tests require {lib} but it is not installed"
+
+        if ver < version.parse(min_ver):
+            return f"snapshot tests require {lib}>={min_ver} but {ver} is installed"
+
+    return None
+
+
+def pytest_configure(config):
+    if config.option.update_snapshots:
+        from importlib import metadata  # Added in 3.8
+
+        for lib, min_ver in SNAPSHOT_MINIMUM_VERSIONS.items():
+            ver = version.parse(metadata.version(lib))
+            if ver != version.parse(min_ver):
+                pytest.exit(
+                    f"snapshots must be generated with {lib}=={min_ver}"
+                    f" or SNAPSHOT_MINIMUM_VERSIONS must be updated to {ver}"
+                    f" in {__file__}"
+                )
+        return
+
+    reason = _snapshot_skip_reason()
+    if reason:
+        config.issue_config_time_warning(UserWarning(reason), stacklevel=2)
         config.option.warn_unused_snapshots = True
+
+
+def pytest_collection_modifyitems(config, items):
+    reason = _snapshot_skip_reason()
+    if reason:
+        for item in items:
+            if "snap_compare" in item.fixturenames:
+                item.add_marker(pytest.mark.skip(reason=reason))

tests/unit/test_tree_reporter.py

@@ -1,4 +1,3 @@
-import sys
 from dataclasses import dataclass
 from textwrap import dedent
 from typing import Any
@@ -1534,15 +1533,6 @@ def test_render_runs_the_app(self):
 
 @pytest.fixture
 def compare(monkeypatch, tmp_path, snap_compare):
-    # The snapshots we've generated using current versions of Textual aren't
-    # expected to match anymore on Python 3.7, as Textual dropped support for
-    # Python 3.7 in the 0.44 release. However, we'd still like to run our
-    # snapshot tests on Python 3.7, to confirm that no unexpected exceptions
-    # occur and that the app doesn't crash. So, allow `snap_compare()` to drive
-    # the application, but always return `True` on Python 3.7 as long as no
-    # exception was raised.
-    succeed_even_if_mismatched = sys.version_info < (3, 8)
-
     def compare_impl(
         allocations: Iterator[AllocationRecord],
         press: Iterable[str] = (),
@@ -1561,14 +1551,11 @@ def compare_impl(
         with monkeypatch.context() as app_patch:
             app_patch.setitem(globals(), app_global, app)
             tmp_main.write_text(f"from {__name__} import {app_global} as app")
-            return (
-                snap_compare(
-                    str(tmp_main),
-                    press=press,
-                    terminal_size=terminal_size,
-                    run_before=run_before,
-                )
-                or succeed_even_if_mismatched
+            return snap_compare(
+                str(tmp_main),
+                press=press,
+                terminal_size=terminal_size,
+                run_before=run_before,
             )
 
     yield compare_impl

tests/unit/test_tui_reporter.py

@@ -1,6 +1,5 @@
 import asyncio
 import datetime
-import sys
 from io import StringIO
 from typing import Awaitable
 from typing import Callable
@@ -103,15 +102,6 @@ def get_current_snapshot(
 def compare(monkeypatch, tmp_path, snap_compare):
     monkeypatch.setattr(memray.reporters.tui, "datetime", FakeDatetime)
 
-    # The snapshots we've generated using current versions of Textual aren't
-    # expected to match anymore on Python 3.7, as Textual dropped support for
-    # Python 3.7 in the 0.44 release. However, we'd still like to run our
-    # snapshot tests on Python 3.7, to confirm that no unexpected exceptions
-    # occur and that the app doesn't crash. So, allow `snap_compare()` to drive
-    # the application, but always return `True` on Python 3.7 as long as no
-    # exception was raised.
-    succeed_even_if_mismatched = sys.version_info < (3, 8)
-
     def compare_impl(
         cmdline_override: Optional[str] = None,
         press: Iterable[str] = (),
@@ -138,14 +128,11 @@ async def run_before_wrapper(pilot) -> None:
         with monkeypatch.context() as app_patch:
             app_patch.setitem(globals(), app_global, app)
             tmp_main.write_text(f"from {__name__} import {app_global} as app")
-            return (
-                snap_compare(
-                    str(tmp_main),
-                    press=press,
-                    terminal_size=terminal_size,
-                    run_before=run_before_wrapper,
-                )
-                or succeed_even_if_mismatched
+            return snap_compare(
+                str(tmp_main),
+                press=press,
+                terminal_size=terminal_size,
+                run_before=run_before_wrapper,
             )
 
     yield compare_impl