Improve psydac test command (#567)

### Main changes

- Allow selecting a specific test function in a module by passing `--mod
test_<MODULE>::test_<FUNCTION>`
- Pass `--dist loadgroup` to group test execution by the `xdist_group`
mark (see the documentation of
[pytest-xdist](https://pytest-xdist.readthedocs.io/en/stable/distribution.html#running-tests-across-multiple-cpus)),
which allows running non-thread-safe tests sequentially on a single
runner
- Remove local `.pytest_cache` folder before running tests
- Move `pytest.ini` to package root, so it can be used after
installation
- If not present, copy `pytest.ini` to local working directory before
running tests

### Additional changes

- Fix the parallel creation of the folder `__psydac__` in
`psydac.api.fem_bilinear_form`: only root process creates it

Author: yguclu

psydac/api/fem_bilinear_form.py

@@ -1440,12 +1440,12 @@ def make_file(self, temps, ordered_stmts, field_derivatives, max_logical_derivat
         assembly_code += '\n    return\n'
 
         #------------------------- MAKE FILE -------------------------
-        import os
-        if not os.path.isdir('__psydac__'):
-            os.makedirs('__psydac__')
 
         # Root process writes the assembly code to a file
         if comm is None or comm.rank == 0:
+            import os
+            if not os.path.isdir('__psydac__'):
+                os.makedirs('__psydac__')
             filename = f'__psydac__/assemble_{file_id}.py'
             f = open(filename, 'w')
             f.writelines(assembly_code)
@@ -1996,26 +1996,23 @@ def construct_arguments_generate_assembly_file(self):
         assembly_backend = self.backend
         if self._pyccelize_test_trial_computation and assembly_backend['name'] == 'pyccel':
 
-            import os
-            if not os.path.isdir('__psydac__'):
-                os.makedirs('__psydac__')
-
             comm = self.comm
 
-            if comm is not None and comm.size > 1:
-                if comm.rank == 0:
-                    filename = '__psydac__/test_trial_computation.py'
-                    code = self.test_trial_template
-                    f = open(filename, 'w')
-                    f.writelines(code)
-                    f.close()
-            else:
+            # Root process writes the assembly code to a file
+            if comm is None or comm.rank == 0:
+                import os
+                if not os.path.isdir('__psydac__'):
+                    os.makedirs('__psydac__')
                 filename = '__psydac__/test_trial_computation.py'
                 code = self.test_trial_template
                 f = open(filename, 'w')
                 f.writelines(code)
                 f.close()
 
+            # Parallel case: wait for the file to be closed before proceeding
+            if comm is not None and comm.size > 1:
+                _ = comm.bcast(None, root=0)
+
             base_dirpath = os.getcwd()
             sys.path.insert(0, base_dirpath)
 

psydac/cmd/psydac_test.py

@@ -72,17 +72,37 @@ def psydac_test(*, mod, mpi, petsc, verbose, exitfirst):
         elif submods[0] != 'psydac':
             exit_with_error_message("module name must start with 'psydac'")
         try:
+            modname = mod.split('::')[0]
             import importlib
-            importlib.import_module(mod)
+            importlib.import_module(modname)
         except ImportError:
-            exit_with_error_message(f"module '{mod}' not found")
+            exit_with_error_message(f"module '{modname}' not found")
 
     # Import modules here to speed up parser
     import os
     import shutil
     import subprocess
     import time
 
+    # Clear Pytest cache from the current working directory
+    cache_dir = '.pytest_cache'
+    if os.path.isdir(cache_dir):
+        print(f'Removing existing Pytest cache directory: {cache_dir}\n', flush=True)
+        shutil.rmtree(cache_dir)
+
+    # If no pytest.ini file exists in the current working directory, copy it
+    # from the parent directory of this script (which is installed with PSYDAC)
+    if not os.path.isfile('pytest.ini'):
+        script_dir = os.path.dirname(os.path.abspath(__file__))
+        parent_dir = os.path.dirname(script_dir)
+        pytest_ini = os.path.join(parent_dir, 'pytest.ini')
+        if not os.path.isfile(pytest_ini):
+            exit_with_error_message(f'could not find pytest.ini file in {parent_dir}')
+        else:
+            print(f'Copying pytest.ini from: {parent_dir}\n', flush=True)
+            shutil.copy(pytest_ini, os.getcwd())
+
+    # Build the list of flags for pytest
     flags = []
 
     # Set up MPI execution command, if needed
@@ -112,7 +132,7 @@ def psydac_test(*, mod, mpi, petsc, verbose, exitfirst):
 
     else:
         mpi_exe = []
-        flags.extend(['-n', 'auto'])
+        flags.extend(['-n', 'auto', '--dist', 'loadgroup'])  # for pytest-xdist
 
     # If PETSc tests are requested, check that petsc4py is installed
     if petsc: