[ci] Fix python_package_basic tests error: pep517.wrappers.BackendUnavailable

opacam · opacam · commit f74d4f34d1f7 · 2019-05-19T11:24:09.000+02:00
This error is raised when we try to get the metadata from a package and this happens because we forgot to first install the build requirements from the `pyproject.toml` file
diff --git a/pythonforandroid/pythonpackage.py b/pythonforandroid/pythonpackage.py
@@ -436,10 +436,11 @@ def _extract_metainfo_files_from_package_unsafe(
                 os.path.join(output_path, 'pyproject.toml')
             )
 
-            # Get build backend from pyproject.toml:
+            # Get build backend and requirements from pyproject.toml:
             with open(os.path.join(path, 'pyproject.toml')) as f:
                 build_sys = pytoml.load(f)['build-system']
                 backend = build_sys["build-backend"]
+                build_requires.extend(build_sys["requires"])
 
             # Get a virtualenv with build requirements and get all metadata:
             env = BuildEnvironment()
