cachekey.py: Move source tests for cache keys in sourcetests

This now expectes plugin authors to provide the elements and expected
cache keys for their sources.

2 files changed, 85 insertions, 0 deletions

diff --git a/src/buildstream/testing/_sourcetests/cachekey.py b/src/buildstream/testing/_sourcetests/cachekey.py
new file mode 100644
index 000000000..3c8724476
--- /dev/null
+++ b/src/buildstream/testing/_sourcetests/cachekey.py
@@ -0,0 +1,73 @@
+#
+#  Copyright (C) 2019 Bloomberg Finance LP
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU Lesser General Public
+#  License as published by the Free Software Foundation; either
+#  version 2 of the License, or (at your option) any later version.
+#
+#  This library is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+#  Lesser General Public License for more details.
+#
+#  You should have received a copy of the GNU Lesser General Public
+#  License along with this library. If not, see <http://www.gnu.org/licenses/>.
+#
+
+# Pylint doesn't play well with fixtures and dependency injection from pytest
+# pylint: disable=redefined-outer-name
+
+import os
+import pytest
+
+from buildstream import _yaml
+from .. import cli  # pylint: disable=unused-import
+from .. import create_repo
+from .._utils.site import IS_LINUX, MACHINE_ARCH
+from .utils import kind  # pylint: disable=unused-import
+
+
+# Project directory
+TOP_DIR = os.path.dirname(os.path.realpath(__file__))
+DATA_DIR = os.path.join(TOP_DIR, "project")
+
+
+@pytest.mark.skipif(MACHINE_ARCH != "x86-64", reason="Cache keys depend on architecture")
+@pytest.mark.skipif(not IS_LINUX, reason="Only available on linux")
+@pytest.mark.datafiles(DATA_DIR)
+def test_cache_key(cli, tmpdir, datafiles, kind):
+    project = str(datafiles)
+    elements_path = os.path.join(project, "elements")
+
+    # Create our repo object of the given source type with
+    # the bin files, and then collect the initial ref.
+    #
+    repo = create_repo(kind, str(tmpdir))
+
+    test_elements = repo.get_element_and_keys_for_cache_key_stability_test()
+
+    expected_cache_keys = {}
+
+    for index, (element, cache_key) in enumerate(test_elements):
+        element_name = "{}-{}.bst".format(kind, index)
+        _yaml.roundtrip_dump(element, os.path.join(elements_path, element_name))
+        expected_cache_keys[element_name] = cache_key
+
+    result = cli.run(
+        project=project,
+        silent=True,
+        args=["show", "--format", "%{name}::{%full-key}", *expected_cache_keys.keys()]
+    )
+    result.assert_success()
+    cache_keys = {
+        [l.split("::") for l in result.output.splitlines()]
+    }
+
+    error_msg = """\
+A cache key needs an update, some keys have changes.
+You will need to update the `repo` for {} and change the key
+it returns.
+""".format(kind)
+
+    assert expected_cache_keys == cache_keys, error_msg
diff --git a/src/buildstream/testing/repo.py b/src/buildstream/testing/repo.py
index 1b46ec806..a190429ed 100644
--- a/src/buildstream/testing/repo.py
+++ b/src/buildstream/testing/repo.py
@@ -23,6 +23,7 @@ Repo - Utility class for testing source plugins
 """
 import os
 import shutil
+from typing import Dict, List, Tuple
 
 
 class Repo:
@@ -108,3 +109,14 @@ class Repo:
         repo_type = type(self)
         new_repo = repo_type(dest, subdir)
         return new_repo
+
+    def get_element_and_keys_for_cache_key_stability_test(self) -> List[Tuple[Dict, str]]:
+        """Get a list of element content files and their expected cache key.
+
+        This should return a list of BuildStream elements together with the
+        cache key they are expected to have.
+
+        This ensures that sources don't unintentionally break their cache keys
+        and that BuildStream itself doesn't either.
+        """
+        raise NotImplementedError("Element cache keys tests should be implemented")