Mock storage space checks for tests.BenjaminSchubert/fix-quota-tests

Fix #530

- Extract free space computation in a function for easier
mocking
- Mock space computation during cache quota tests
- Mock cache size during cachque quota tests
- Add two more tests when the configuration would require
to much storage space

4 files changed, 59 insertions, 57 deletions

diff --git a/buildstream/_artifactcache/artifactcache.py b/buildstream/_artifactcache/artifactcache.py
index 7771851ae..b4b8df320 100644
--- a/buildstream/_artifactcache/artifactcache.py
+++ b/buildstream/_artifactcache/artifactcache.py
@@ -874,9 +874,7 @@ class ArtifactCache():
                             "\nValid values are, for example: 800M 10G 1T 50%\n"
                             .format(str(e))) from e
 
-        stat = os.statvfs(artifactdir_volume)
-        available_space = (stat.f_bsize * stat.f_bavail)
-
+        available_space, total_size = self._get_volume_space_info_for(artifactdir_volume)
         cache_size = self.get_cache_size()
 
         # Ensure system has enough storage for the cache_quota
@@ -893,7 +891,7 @@ class ArtifactCache():
                             "BuildStream requires a minimum cache quota of 2G.")
         elif cache_quota > cache_size + available_space:  # Check maximum
             if '%' in self.context.config_cache_quota:
-                available = (available_space / (stat.f_blocks * stat.f_bsize)) * 100
+                available = (available_space / total_size) * 100
                 available = '{}% of total disk space'.format(round(available, 1))
             else:
                 available = utils._pretty_size(available_space)
@@ -919,6 +917,20 @@ class ArtifactCache():
         self._cache_quota = cache_quota - headroom
         self._cache_lower_threshold = self._cache_quota / 2
 
+    # _get_volume_space_info_for
+    #
+    # Get the available space and total space for the given volume
+    #
+    # Args:
+    #     volume: volume for which to get the size
+    #
+    # Returns:
+    #     A tuple containing first the availabe number of bytes on the requested
+    #     volume, then the total number of bytes of the volume.
+    def _get_volume_space_info_for(self, volume):
+        stat = os.statvfs(volume)
+        return stat.f_bsize * stat.f_bavail, stat.f_bsize * stat.f_blocks
+
 
 # _configured_remote_artifact_cache_specs():
 #
diff --git a/tests/artifactcache/expiry.py b/tests/artifactcache/expiry.py
index 0ac86b91f..05cbe3209 100644
--- a/tests/artifactcache/expiry.py
+++ b/tests/artifactcache/expiry.py
@@ -18,6 +18,7 @@
 #
 
 import os
+from unittest import mock
 
 import pytest
 
@@ -311,6 +312,8 @@ def test_never_delete_required_track(cli, datafiles, tmpdir):
     ("0", True),
     ("-1", False),
     ("pony", False),
+    ("7K", False),
+    ("70%", False),
     ("200%", False)
 ])
 @pytest.mark.datafiles(DATA_DIR)
@@ -324,7 +327,35 @@ def test_invalid_cache_quota(cli, datafiles, tmpdir, quota, success):
         }
     })
 
-    res = cli.run(project=project, args=['workspace', 'list'])
+    # We patch how we get space information
+    # Ideally we would instead create a FUSE device on which we control
+    # everything.
+    # If the value is a percentage, we fix the current values to take into
+    # account the block size, since this is important in how we compute the size
+
+    if quota.endswith("%"):  # We set the used space at 60% of total space
+        stats = os.statvfs(".")
+        free_space = 0.6 * stats.f_bsize * stats.f_blocks
+        total_space = stats.f_bsize * stats.f_blocks
+    else:
+        free_space = 6000
+        total_space = 10000
+
+    volume_space_patch = mock.patch(
+        "buildstream._artifactcache.artifactcache.ArtifactCache._get_volume_space_info_for",
+        autospec=True,
+        return_value=(free_space, total_space),
+    )
+
+    cache_size_patch = mock.patch(
+        "buildstream._artifactcache.artifactcache.ArtifactCache.get_cache_size",
+        autospec=True,
+        return_value=0,
+    )
+
+    with volume_space_patch, cache_size_patch:
+        res = cli.run(project=project, args=['workspace', 'list'])
+
     if success:
         res.assert_success()
     else:
diff --git a/tests/testutils/mock_os.py b/tests/testutils/mock_os.py
deleted file mode 100644
index 109593b16..000000000
--- a/tests/testutils/mock_os.py
+++ /dev/null
@@ -1,44 +0,0 @@
-from contextlib import contextmanager
-import os
-
-
-# MockAttributeResult
-#
-# A class to take a dictionary of kwargs and make them accessible via
-# attributes of the object.
-#
-class MockAttributeResult(dict):
-    __getattr__ = dict.get
-
-
-# mock_statvfs():
-#
-# Gets a function which mocks statvfs and returns a statvfs result with the kwargs accessible.
-#
-# Returns:
-#    func(path) -> object: object will have all the kwargs accessible via object.kwarg
-#
-# Example:
-#    statvfs = mock_statvfs(f_blocks=10)
-#    result = statvfs("regardless/of/path")
-#    assert result.f_blocks == 10 # True
-def mock_statvfs(**kwargs):
-    def statvfs(path):
-        return MockAttributeResult(kwargs)
-    return statvfs
-
-
-# monkey_patch()
-#
-# with monkey_patch("statvfs", custom_statvfs):
-#    assert os.statvfs == custom_statvfs # True
-# assert os.statvfs == custom_statvfs # False
-#
-@contextmanager
-def monkey_patch(to_patch, patched_func):
-    orig = getattr(os, to_patch)
-    setattr(os, to_patch, patched_func)
-    try:
-        yield
-    finally:
-        setattr(os, to_patch, orig)
diff --git a/tests/utils/misc.py b/tests/utils/misc.py
index 7df08aec5..4ab29ad38 100644
--- a/tests/utils/misc.py
+++ b/tests/utils/misc.py
@@ -1,9 +1,9 @@
+import os
+from unittest import mock
+
 from buildstream import _yaml
-from ..testutils import mock_os
-from ..testutils.runcli import cli
 
-import os
-import pytest
+from ..testutils.runcli import cli
 
 
 KiB = 1024
@@ -13,7 +13,6 @@ TiB = (GiB * 1024)
 
 
 def test_parse_size_over_1024T(cli, tmpdir):
-    BLOCK_SIZE = 4096
     cli.configure({
         'cache': {
             'quota': 2048 * TiB
@@ -23,9 +22,13 @@ def test_parse_size_over_1024T(cli, tmpdir):
     os.makedirs(str(project))
     _yaml.dump({'name': 'main'}, str(project.join("project.conf")))
 
-    bavail = (1025 * TiB) / BLOCK_SIZE
-    patched_statvfs = mock_os.mock_statvfs(f_bavail=bavail, f_bsize=BLOCK_SIZE)
-    with mock_os.monkey_patch("statvfs", patched_statvfs):
+    volume_space_patch = mock.patch(
+        "buildstream._artifactcache.artifactcache.ArtifactCache._get_volume_space_info_for",
+        autospec=True,
+        return_value=(1025 * TiB, 1025 * TiB)
+    )
+
+    with volume_space_patch:
         result = cli.run(project, args=["build", "file.bst"])
         failure_msg = 'Your system does not have enough available space to support the cache quota specified.'
         assert failure_msg in result.stderr