tests: add more tests of package traversal (#906)

This PR adds tests (including some xfailed ones) demonstrated patterns
of package/subpackage access via import and importlib that are expected
to work correctly for both normal and editable installs. Related to
#807.

---------

Signed-off-by: Cristian Le <[email protected]>
Co-authored-by: Cristian Le <[email protected]>

Author: vyasr

tests/packages/importlib_editable/CMakeLists.txt

@@ -0,0 +1,13 @@
+cmake_minimum_required(VERSION 3.15...3.26)
+project(${SKBUILD_PROJECT_NAME} LANGUAGES C)
+
+find_package(
+  Python
+  COMPONENTS Interpreter Development.Module
+  REQUIRED)
+
+python_add_library(emod MODULE emod.c WITH_SOABI)
+install(TARGETS emod DESTINATION .)
+install(FILES "${CMAKE_CURRENT_SOURCE_DIR}/pmod.py" DESTINATION .)
+
+add_subdirectory(pkg)

tests/packages/importlib_editable/emod.c

@@ -0,0 +1,25 @@
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+
+float square(float x) { return x * x; }
+
+static PyObject *square_wrapper(PyObject *self, PyObject *args) {
+  float input, result;
+  if (!PyArg_ParseTuple(args, "f", &input)) {
+    return NULL;
+  }
+  result = square(input);
+  return PyFloat_FromDouble(result);
+}
+
+static PyMethodDef emod_methods[] = {
+    {"square", square_wrapper, METH_VARARGS, "Square function"},
+    {NULL, NULL, 0, NULL}};
+
+static struct PyModuleDef emod_module = {PyModuleDef_HEAD_INIT, "emod",
+                                             NULL, -1, emod_methods};
+
+/* name here must match extension name, with PyInit_ prefix */
+PyMODINIT_FUNC PyInit_emod(void) {
+  return PyModule_Create(&emod_module);
+}

tests/packages/importlib_editable/emod.pyi

@@ -0,0 +1 @@
+def square(x: float) -> float: ...

tests/packages/importlib_editable/pkg/CMakeLists.txt

@@ -0,0 +1,8 @@
+python_add_library(emod_a MODULE emod_a.c WITH_SOABI)
+
+install(TARGETS emod_a DESTINATION pkg/)
+file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/testfile" "This is the file")
+install(FILES "${CMAKE_CURRENT_BINARY_DIR}/testfile" DESTINATION pkg/)
+
+add_subdirectory(sub_a)
+add_subdirectory(sub_b)

tests/packages/importlib_editable/pkg/__init__.py

@@ -0,0 +1,32 @@
+# Don't let ruff sort imports in this file, we want to keep them with the comments as is
+# for clarity.
+# ruff: noqa: I001, F401
+# mypy: ignore-errors
+
+# Level zero import global modules
+from pmod import square as psquare
+from emod import square as esquare
+
+# Level one pure modules
+from .pmod_a import square as psquare_a
+
+# Level one extension modules
+from .emod_a import square as esquare_a
+
+# Level one subpackages
+from . import sub_a
+
+# Level two pure modules
+from .sub_a.pmod_b import square as psquare_b
+
+# Level two extension modules
+from .sub_a.emod_b import square as esquare_b
+
+# Level two subpackages
+from .sub_b import sub_c
+
+# Level three pure modules
+from .sub_b.sub_c.pmod_d import square as psquare_d
+
+# Level three extension modules
+from .sub_b.sub_c.emod_d import square as esquare_d

tests/packages/importlib_editable/pkg/emod_a.c

@@ -0,0 +1,25 @@
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+
+float square(float x) { return x * x; }
+
+static PyObject *square_wrapper(PyObject *self, PyObject *args) {
+  float input, result;
+  if (!PyArg_ParseTuple(args, "f", &input)) {
+    return NULL;
+  }
+  result = square(input);
+  return PyFloat_FromDouble(result);
+}
+
+static PyMethodDef emod_a_methods[] = {
+    {"square", square_wrapper, METH_VARARGS, "Square function"},
+    {NULL, NULL, 0, NULL}};
+
+static struct PyModuleDef emod_a_module = {PyModuleDef_HEAD_INIT, "emod_a",
+                                             NULL, -1, emod_a_methods};
+
+/* name here must match extension name, with PyInit_ prefix */
+PyMODINIT_FUNC PyInit_emod_a(void) {
+  return PyModule_Create(&emod_a_module);
+}

tests/packages/importlib_editable/pkg/emod_a.pyi

@@ -0,0 +1 @@
+def square(x: float) -> float: ...

tests/packages/importlib_editable/pkg/pmod_a.py

@@ -0,0 +1,9 @@
+# ruff: noqa: I001, F401
+# mypy: ignore-errors
+
+# Level one import sibling
+from .emod_a import square as esquare
+
+
+def square(x):
+    return x * x

tests/packages/importlib_editable/pkg/sub_a/CMakeLists.txt

@@ -0,0 +1,5 @@
+python_add_library(emod_b MODULE emod_b.c WITH_SOABI)
+
+install(TARGETS emod_b DESTINATION pkg/sub_a)
+file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/testfile" "This is the file")
+install(FILES "${CMAKE_CURRENT_BINARY_DIR}/testfile" DESTINATION pkg/sub_a)

tests/packages/importlib_editable/pkg/sub_a/__init__.py

@@ -0,0 +1,15 @@
+# ruff: noqa: I001, F401
+# mypy: ignore-errors
+
+from .pmod_b import square as psquare
+from .emod_b import square as esquare
+
+# Level one import cousin
+from .. import sub_b
+from ..sub_b.pmod_c import square as psquare_c
+from ..sub_b.emod_c import square as esquare_c
+
+# Level one import distant cousin
+from ..sub_b import sub_c
+from ..sub_b.sub_c.pmod_d import square as psquare_d
+from ..sub_b.sub_c.emod_d import square as esquare_d