Add pytest plugin for automatic .coco test compilation (#888)

coconut/api.py

@@ -309,6 +309,21 @@ def auto_compilation(on=True, args=None, use_cache_dir=None):
 auto_compilation()
 
 
+def install_pytest_plugin():
+    """Install Coconut's pytest plugin. Call this at the top of your conftest.py.
+
+    Injects pytest hook functions directly into the calling module's namespace,
+    which works in any conftest.py regardless of its location. This is the
+    recommended fallback when Coconut is not installed via pip (which would
+    register the plugin automatically via the pytest11 entry point).
+    """
+    import inspect
+    from coconut import pytest_plugin as _plugin
+    frame = inspect.currentframe().f_back
+    for name in ("pytest_configure", "pytest_collect_file", "pytest_ignore_collect"):
+        frame.f_globals[name] = getattr(_plugin, name)
+
+
 # -----------------------------------------------------------------------------------------------------------------------
 # ENCODING:
 # -----------------------------------------------------------------------------------------------------------------------

coconut/pytest_plugin.py

@@ -0,0 +1,122 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# -----------------------------------------------------------------------------------------------------------------------
+# INFO:
+# -----------------------------------------------------------------------------------------------------------------------
+
+"""
+Author: Adam Forest
+License: Apache 2.0
+Description: Pytest plugin for automatic Coconut compilation.
+"""
+
+# -----------------------------------------------------------------------------------------------------------------------
+# IMPORTS:
+# -----------------------------------------------------------------------------------------------------------------------
+
+from __future__ import print_function, absolute_import, unicode_literals, division
+
+from coconut.root import *  # NOQA
+
+import sys
+import io
+
+from coconut.constants import code_exts, coconut_cache_dir
+
+# -----------------------------------------------------------------------------------------------------------------------
+# HELPERS:
+# -----------------------------------------------------------------------------------------------------------------------
+
+
+class _TtyStdin(io.StringIO):
+    """Fake stdin that reports itself as a TTY.
+
+    Under pytest, stdin is captured and raises OSError on read().
+    Coconut's stdin_readable() checks isatty() to decide whether to read;
+    returning True here makes it skip the read entirely.
+    """
+    def isatty(self):
+        return True
+
+
+_pytest_importer = None
+
+
+def _get_pytest_importer():
+    """Get or create the stdin-safe CoconutImporter for use under pytest."""
+    global _pytest_importer
+    if _pytest_importer is None:
+        from coconut.api import CoconutImporter
+
+        class _PytestCoconutImporter(CoconutImporter):
+            """CoconutImporter for use under pytest.
+
+            Compiles in-place (--no-cache) so that the path returned by
+            pytest_collect_file matches what Python's import system loads,
+            avoiding __file__ mismatch errors.
+
+            Overrides find_spec to return a concrete spec pointing to the
+            in-place .py file, preventing the global coconut_importer (which
+            uses a cache dir) from intercepting imports and redirecting to a
+            different path.
+
+            Guards sys.stdin during every compile() call so pytest's stdin
+            capture does not cause OSError.
+            """
+
+            def compile(self, path, package):
+                old_stdin = sys.stdin
+                sys.stdin = _TtyStdin()
+                try:
+                    return super(_PytestCoconutImporter, self).compile(path, package)
+                finally:
+                    sys.stdin = old_stdin
+
+            def find_spec(self, fullname, path=None, target=None):
+                destpath = self.find_coconut(fullname, path)
+                if destpath is None:
+                    return None
+                from importlib.machinery import SourceFileLoader
+                from importlib.util import spec_from_loader
+                return spec_from_loader(fullname, SourceFileLoader(fullname, destpath))
+
+        # --no-cache: compile in-place next to the .coco file so the
+        # collected .py path and module.__file__ always agree.
+        _pytest_importer = _PytestCoconutImporter("--no-cache")
+    return _pytest_importer
+
+
+# -----------------------------------------------------------------------------------------------------------------------
+# HOOKS:
+# -----------------------------------------------------------------------------------------------------------------------
+
+
+def pytest_configure(config):
+    """Register the pytest-safe Coconut importer for the test session."""
+    importer = _get_pytest_importer()
+    if importer not in sys.meta_path:
+        sys.meta_path.insert(0, importer)
+
+
+def pytest_collect_file(file_path, parent):
+    """Compile .coco test files and collect the resulting in-place .py file."""
+    if file_path.suffix in code_exts and file_path.stem.startswith("test_"):
+        from pathlib import Path
+        import pytest
+        importer = _get_pytest_importer()
+        py_path = Path(importer.compile(str(file_path), package=False))
+        return pytest.Module.from_parent(parent, path=py_path)
+
+
+def pytest_ignore_collect(collection_path, config):
+    """Skip cache directories and .py files that have a .coco source alongside them."""
+    # Ignore the entire __coconut_cache__ directory tree
+    if coconut_cache_dir in collection_path.parts:
+        return True
+    # Ignore .py files whose .coco source will be compiled and collected separately
+    if collection_path.suffix == ".py" and collection_path.stem.startswith("test_"):
+        for ext in code_exts:
+            coco_sibling = collection_path.with_suffix(ext)
+            if coco_sibling.exists():
+                return True

setup.py

@@ -85,6 +85,9 @@
         "xonsh.xontribs": [
             "coconut = coconut.integrations",
         ],
+        "pytest11": [
+            "coconut = coconut.pytest_plugin",
+        ],
     },
     classifiers=list(classifiers),
     keywords=list(search_terms),