_remote: Ensure checks done in the subclasses are propagated

Currently, the `BaseRemote` would call `_check()` on the children, which
states that errors should be sent back as a string. However,
`BaseRemote` doesn't check the return of `_check()`.

This changes the contract so that subclasses throw `RemoteError`
themselves.

This also fixes the `ArtifactShare` and add a test.

1 files changed, 55 insertions, 0 deletions

diff --git a/tests/artifactcache/capabilities.py b/tests/artifactcache/capabilities.py
new file mode 100644
index 000000000..a28516aea
--- /dev/null
+++ b/tests/artifactcache/capabilities.py
@@ -0,0 +1,55 @@
+# Pylint doesn't play well with fixtures and dependency injection from pytest
+# pylint: disable=redefined-outer-name
+
+import os
+
+import pytest
+from buildstream._project import Project
+
+from buildstream import _yaml
+from buildstream.testing.runcli import cli  # pylint: disable=unused-import
+from tests.testutils import dummy_context
+
+from tests.testutils.artifactshare import create_dummy_artifact_share
+
+
+DATA_DIR = os.path.join(
+    os.path.dirname(os.path.realpath(__file__)),
+    "project",
+)
+
+
+@pytest.mark.datafiles(DATA_DIR)
+def test_artifact_cache_with_missing_capabilities_is_skipped(cli, tmpdir, datafiles):
+    project_dir = str(datafiles)
+
+    # Set up an artifact cache.
+    with create_dummy_artifact_share() as share:
+        # Configure artifact share
+        cache_dir = os.path.join(str(tmpdir), 'cache')
+        user_config_file = str(tmpdir.join('buildstream.conf'))
+        user_config = {
+            'scheduler': {
+                'pushers': 1
+            },
+            'artifacts': {
+                'url': share.repo,
+                'push': True,
+            },
+            'cachedir': cache_dir
+        }
+        _yaml.roundtrip_dump(user_config, file=user_config_file)
+
+        with dummy_context(config=user_config_file) as context:
+            # Load the project
+            project = Project(project_dir, context)
+            project.ensure_fully_loaded()
+
+            # Create a local artifact cache handle
+            artifactcache = context.artifactcache
+
+            # Manually setup the CAS remote
+            artifactcache.setup_remotes(use_config=True)
+
+            assert not artifactcache.has_fetch_remotes(), \
+                "System didn't realize the artifact cache didn't support BuildStream"