[tracker-miners/sam/test-runner-fix] functional-tests: Rationalize handling of temporary directories

[Sam Thursfield <sthursfield src gnome org>]

commit 69cda40c996ab52c39fba40815b513e939946d0d
Author: Sam Thursfield <sam afuera me uk>
Date:   Sat Jan 5 15:38:27 2019 +0100

    functional-tests: Rationalize handling of temporary directories
    
    Tests were sharing a test directory, which caused issues when they were
    run in parallel by Meson.
    
    As a bonus, we now clean up the ~/tracker-tests directory on successful
    test runs.

 tests/functional-tests/300-miner-basic-ops.py      | 16 ++---
 tests/functional-tests/410-extractor-decorator.py  | 17 ++---
 .../common/utils/applicationstest.py               | 42 +++++-------
 .../functional-tests/common/utils/configuration.py | 43 +++++++++---
 tests/functional-tests/common/utils/minertest.py   | 18 +++--
 tests/functional-tests/common/utils/system.py      | 77 +++++++++++++--------
 .../functional-tests/common/utils/writebacktest.py | 78 ++++++++++------------
 7 files changed, 151 insertions(+), 140 deletions(-)
---
diff --git a/tests/functional-tests/300-miner-basic-ops.py b/tests/functional-tests/300-miner-basic-ops.py
index afcf6285b..ba8efea66 100755
--- a/tests/functional-tests/300-miner-basic-ops.py
+++ b/tests/functional-tests/300-miner-basic-ops.py
@@ -94,8 +94,8 @@ class MinerCrawlTest (CommonTrackerMinerTest):
         Copy an file from unmonitored directory to monitored directory
         and verify if data base is updated accordingly
         """
-        source = os.path.join (self.datadir, "test-no-monitored", "file0.txt")
-        dest = os.path.join (self.datadir, "test-monitored", "file0.txt")
+        source = os.path.join (self.workdir, "test-no-monitored", "file0.txt")
+        dest = os.path.join (self.workdir, "test-monitored", "file0.txt")
         shutil.copyfile (source, dest)
 
         dest_id, dest_urn = self.system.store.await_resource_inserted (NFO_DOCUMENT, self.uri(dest))
@@ -121,8 +121,8 @@ class MinerCrawlTest (CommonTrackerMinerTest):
         """
 
         # Copy from monitored to unmonitored
-        source = os.path.join (self.datadir, "test-monitored", "file1.txt")
-        dest = os.path.join (self.datadir, "test-no-monitored", "file1.txt")
+        source = os.path.join (self.workdir, "test-monitored", "file1.txt")
+        dest = os.path.join (self.workdir, "test-no-monitored", "file1.txt")
         shutil.copyfile (source, dest)
 
         time.sleep (1)
@@ -141,8 +141,8 @@ class MinerCrawlTest (CommonTrackerMinerTest):
         """
         Copy a file between monitored directories
         """
-        source = os.path.join (self.datadir, "test-monitored", "file1.txt")
-        dest = os.path.join (self.datadir, "test-monitored", "dir1", "dir2", "file-test04.txt")
+        source = os.path.join (self.workdir, "test-monitored", "file1.txt")
+        dest = os.path.join (self.workdir, "test-monitored", "dir1", "dir2", "file-test04.txt")
         shutil.copyfile (source, dest)
 
         dest_id, dest_urn = self.system.store.await_resource_inserted (NFO_DOCUMENT, self.uri(dest))
@@ -165,8 +165,8 @@ class MinerCrawlTest (CommonTrackerMinerTest):
         """
         Move a file from unmonitored to monitored directory
         """
-        source = os.path.join (self.datadir, "test-no-monitored", "file0.txt")
-        dest = os.path.join (self.datadir, "test-monitored", "dir1", "file-test05.txt")
+        source = os.path.join (self.workdir, "test-no-monitored", "file0.txt")
+        dest = os.path.join (self.workdir, "test-monitored", "dir1", "file-test05.txt")
         shutil.move (source, dest)
         dest_id, dest_urn = self.system.store.await_resource_inserted (NFO_DOCUMENT, self.uri(dest))
 
diff --git a/tests/functional-tests/410-extractor-decorator.py 
b/tests/functional-tests/410-extractor-decorator.py
index 046fd7c21..52caeb4c9 100755
--- a/tests/functional-tests/410-extractor-decorator.py
+++ b/tests/functional-tests/410-extractor-decorator.py
@@ -47,18 +47,9 @@ VALID_FILE_TITLE = 'Simply Juvenile'
 
 TRACKER_EXTRACT_FAILURE_DATA_SOURCE = 'tracker:extractor-failure-data-source'
 
-def ensure_dir_exists(dirname):
-    if not os.path.exists(dirname):
-        os.makedirs(dirname)
-
-
 class ExtractorDecoratorTest(ut.TestCase):
     def setUp(self):
-        ensure_dir_exists(cfg.TEST_MONITORED_TMP_DIR)
-
-        # It's important that this directory is NOT inside /tmp, because
-        # monitoring files in /tmp usually doesn't work.
-        self.datadir = tempfile.mkdtemp(dir=cfg.TEST_MONITORED_TMP_DIR)
+        self.datadir = cfg.create_monitored_test_dir()
 
         config = {
             cfg.DCONF_MINER_SCHEMA: {
@@ -76,9 +67,9 @@ class ExtractorDecoratorTest(ut.TestCase):
         self.system.tracker_miner_fs_testing_start()
 
     def tearDown(self):
-        self.system.tracker_miner_fs_testing_stop()
+        self.system.finish()
 
-        shutil.rmtree(self.datadir)
+        cfg.remove_monitored_test_dir(self.datadir)
 
     def test_reextraction(self):
         """Tests whether known files are still re-extracted on user request."""
@@ -110,6 +101,8 @@ class ExtractorDecoratorTest(ut.TestCase):
         assert len(title_result) == 1
         self.assertEqual(title_result[0][0], VALID_FILE_TITLE)
 
+        os.remove(file_path)
+
 
 if __name__ == '__main__':
     ut.main()
diff --git a/tests/functional-tests/common/utils/applicationstest.py 
b/tests/functional-tests/common/utils/applicationstest.py
index 72a8b84c8..046e31406 100644
--- a/tests/functional-tests/common/utils/applicationstest.py
+++ b/tests/functional-tests/common/utils/applicationstest.py
@@ -28,18 +28,6 @@ import shutil
 import os
 import time
 
-APPLICATIONS_TMP_DIR = os.path.join (cfg.TEST_MONITORED_TMP_DIR, "test-applications-monitored")
-
-index_dirs = [APPLICATIONS_TMP_DIR]
-CONF_OPTIONS = {
-    cfg.DCONF_MINER_SCHEMA: {
-        'index-recursive-directories': GLib.Variant.new_strv(index_dirs),
-        'index-single-directories': GLib.Variant.new_strv([]),
-        'index-optical-discs': GLib.Variant.new_boolean(False),
-        'index-removable-devices': GLib.Variant.new_boolean(False),
-    }
-}
-
 # Copy rate, 10KBps (1024b/100ms)
 SLOWCOPY_RATE = 1024
 
@@ -68,7 +56,7 @@ class CommonTrackerApplicationTest (ut.TestCase):
         return self.datadir
 
     def get_dest_dir (self):
-        return APPLICATIONS_TMP_DIR
+        return self.workdir
 
     def slowcopy_file_fd (self, src, fdest, rate=SLOWCOPY_RATE):
         """
@@ -94,10 +82,18 @@ class CommonTrackerApplicationTest (ut.TestCase):
 
     @classmethod
     def setUp (self):
-        # Create temp directory to monitor
-        if (os.path.exists (APPLICATIONS_TMP_DIR)):
-            shutil.rmtree (APPLICATIONS_TMP_DIR)
-        os.makedirs (APPLICATIONS_TMP_DIR)
+        self.workdir = cfg.create_monitored_test_dir()
+
+        index_dirs = [self.workdir]
+
+        CONF_OPTIONS = {
+            cfg.DCONF_MINER_SCHEMA: {
+                'index-recursive-directories': GLib.Variant.new_strv(index_dirs),
+                'index-single-directories': GLib.Variant.new_strv([]),
+                'index-optical-discs': GLib.Variant.new_boolean(False),
+                'index-removable-devices': GLib.Variant.new_boolean(False),
+            }
+        }
 
         # Use local directory if available. Installation otherwise.
         if os.path.exists (os.path.join (os.getcwd (),
@@ -109,20 +105,12 @@ class CommonTrackerApplicationTest (ut.TestCase):
                                          "tracker-tests",
                                          "test-apps-data")
 
-
         self.system = TrackerSystemAbstraction ()
         self.system.tracker_all_testing_start (CONF_OPTIONS)
-
-        # Returns when ready
         self.tracker = self.system.store
 
-        log ("Ready to go!")
-
     @classmethod
     def tearDown (self):
-        #print "Stopping the daemon in test mode (Doing nothing now)"
-        self.system.tracker_all_testing_stop ()
+        self.system.finish ()
 
-        # Remove monitored directory
-        if (os.path.exists (APPLICATIONS_TMP_DIR)):
-            shutil.rmtree (APPLICATIONS_TMP_DIR)
+        cfg.remove_monitored_test_dir(self.workdir)
diff --git a/tests/functional-tests/common/utils/configuration.py 
b/tests/functional-tests/common/utils/configuration.py
index 0c4d65610..12b187383 100644
--- a/tests/functional-tests/common/utils/configuration.py
+++ b/tests/functional-tests/common/utils/configuration.py
@@ -20,8 +20,11 @@
 
 "Constants describing Tracker D-Bus services"
 
+import errno
 import json
 import os
+import tempfile
+
 
 if 'TRACKER_FUNCTIONAL_TEST_CONFIG' not in os.environ:
     raise RuntimeError("The TRACKER_FUNCTIONAL_TEST_CONFIG environment "
@@ -86,22 +89,42 @@ TRACKER_WRITEBACK_PATH = os.path.normpath(expandvars(config['TRACKER_WRITEBACK_P
 
 DATADIR = os.path.normpath(expandvars(config['RAW_DATAROOT_DIR']))
 
-TEST_TMP_DIR = os.path.join (os.environ["HOME"], "tracker-tests")
+def generated_ttl_dir():
+    return os.path.join(TOP_BUILD_DIR, 'tests', 'functional-tests', 'ttl')
 
-TEST_MONITORED_TMP_DIR = TEST_TMP_DIR
 
-if TEST_TMP_DIR.startswith('/tmp'):
+# This path is used for test data for tests which expect filesystem monitoring
+# to work. For this reason we must avoid it being on a tmpfs filesystem. Note
+# that this MUST NOT be a hidden directory, as Tracker is hardcoded to ignore
+# those. The 'ignore-files' configuration option can be changed, but the
+# 'filter-hidden' property of TrackerIndexingTree is hardwired to be True at
+# present :/
+_TEST_MONITORED_TMP_DIR = os.path.join (os.environ["HOME"], "tracker-tests")
+if _TEST_MONITORED_TMP_DIR.startswith('/tmp'):
     if os.environ.has_key('REAL_HOME'):
-        # Note that this MUST NOT be a hidden directory, as Tracker is
-        # hardcoded to ignore those. The 'ignore-files' configuration option
-        # can be changed, but the 'filter-hidden' property of
-        # TrackerIndexingTree is hardwired to be True at present :/
-        TEST_MONITORED_TMP_DIR = os.path.join (os.environ["REAL_HOME"], "tracker-tests")
+        _TEST_MONITORED_TMP_DIR = os.path.join (os.environ["REAL_HOME"], "tracker-tests")
     else:
         print ("HOME is in the /tmp prefix - this will cause tests that rely " +
                 "on filesystem monitoring to fail as changes in that prefix are " +
                 "ignored.")
 
 
-def generated_ttl_dir():
-    return os.path.join(TOP_BUILD_DIR, 'tests', 'functional-tests', 'ttl')
+def create_monitored_test_dir():
+    '''Returns a unique tmpdir which supports filesystem monitor events.'''
+    if not os.path.exists(_TEST_MONITORED_TMP_DIR):
+        os.makedirs(_TEST_MONITORED_TMP_DIR)
+    return tempfile.mkdtemp(dir=_TEST_MONITORED_TMP_DIR)
+
+
+def remove_monitored_test_dir(path):
+    # This will fail if the directory is not empty.
+    os.rmdir(path)
+
+    # We delete the parent directory if possible, to avoid cluttering the user's
+    # home dir, but there may be other tests running in parallel so we ignore
+    # an error if there are still files present in it.
+    try:
+        os.rmdir(_TEST_MONITORED_TMP_DIR)
+    except OSError as e:
+        if e.errno == errno.ENOTEMPTY:
+            pass
diff --git a/tests/functional-tests/common/utils/minertest.py 
b/tests/functional-tests/common/utils/minertest.py
index 0a33331c6..efba55c00 100644
--- a/tests/functional-tests/common/utils/minertest.py
+++ b/tests/functional-tests/common/utils/minertest.py
@@ -43,13 +43,9 @@ def ensure_dir_exists(dirname):
 
 class CommonTrackerMinerTest (ut.TestCase):
     def setUp (self):
-        ensure_dir_exists(cfg.TEST_MONITORED_TMP_DIR)
+        self.workdir = cfg.create_monitored_test_dir()
 
-        # It's important that this directory is NOT inside /tmp, because
-        # monitoring files in /tmp usually doesn't work.
-        self.datadir = tempfile.mkdtemp(dir=cfg.TEST_MONITORED_TMP_DIR)
-
-        self.indexed_dir = os.path.join(self.datadir, 'test-monitored')
+        self.indexed_dir = os.path.join(self.workdir, 'test-monitored')
 
         # It's important that this directory exists BEFORE we start Tracker:
         # it won't monitor an indexing root for changes if it doesn't exist,
@@ -90,14 +86,15 @@ class CommonTrackerMinerTest (ut.TestCase):
             raise
 
     def tearDown (self):
+        self.system.finish ()
         self.remove_test_data ()
-        self.system.tracker_miner_fs_testing_stop ()
+        cfg.remove_monitored_test_dir(self.workdir)
 
     def path (self, filename):
-        return os.path.join (self.datadir, filename)
+        return os.path.join (self.workdir, filename)
 
     def uri (self, filename):
-        return "file://" + os.path.join (self.datadir, filename)
+        return "file://" + os.path.join (self.workdir, filename)
 
     def create_test_data (self):
         monitored_files = [
@@ -121,7 +118,8 @@ class CommonTrackerMinerTest (ut.TestCase):
 
     def remove_test_data(self):
         try:
-            shutil.rmtree(self.datadir)
+            shutil.rmtree(os.path.join(self.workdir, 'test-monitored'))
+            shutil.rmtree(os.path.join(self.workdir, 'test-no-monitored'))
         except Exception as e:
             log("Failed to remove temporary data dir: %s" % e)
 
diff --git a/tests/functional-tests/common/utils/system.py b/tests/functional-tests/common/utils/system.py
index 010b7bfa5..1fbf8b967 100644
--- a/tests/functional-tests/common/utils/system.py
+++ b/tests/functional-tests/common/utils/system.py
@@ -2,6 +2,7 @@
 import os
 import subprocess
 import shutil
+import tempfile
 import configuration as cfg
 
 from gi.repository import GObject
@@ -13,17 +14,8 @@ from dconf import DConfClient
 
 import helpers
 
-# Add this after fixing the backup/restore and ontology changes tests
-#"G_DEBUG" : "fatal_criticals",
-
-TEST_ENV_DIRS =  { "XDG_DATA_HOME" : os.path.join (cfg.TEST_TMP_DIR, "data"),
-                   "XDG_CACHE_HOME": os.path.join (cfg.TEST_TMP_DIR, "cache")}
-
 TEST_ENV_VARS = {  "LC_COLLATE": "en_GB.utf8" }
 
-EXTRA_DIRS = [os.path.join (cfg.TEST_TMP_DIR, "data", "tracker"),
-              os.path.join (cfg.TEST_TMP_DIR, "cache", "tracker")]
-
 REASONABLE_TIMEOUT = 5
 
 class UnableToBootException (Exception):
@@ -32,9 +24,22 @@ class UnableToBootException (Exception):
 
 class TrackerSystemAbstraction (object):
     def __init__(self, settings=None, ontodir=None):
+        self._basedir = None
+
+        self.extractor = None
+        self.miner_fs = None
+        self.store = None
+        self.writeback = None
+
         self.set_up_environment (settings=settings, ontodir=ontodir)
         self.store = None
 
+    def xdg_data_home(self):
+        return os.path.join(self._basedir, 'data')
+
+    def xdg_cache_home(self):
+        return os.path.join(self._basedir, 'cache')
+
     def set_up_environment (self, settings=None, ontodir=None):
         """
         Sets up the XDG_*_HOME variables and make sure the directories exist
@@ -45,30 +50,28 @@ class TrackerSystemAbstraction (object):
         GLib.Variant instance.
         """
 
-        helpers.log ("[Conf] Setting test environment...")
+        self._basedir = tempfile.mkdtemp()
 
-        for var, directory in TEST_ENV_DIRS.iteritems ():
-            helpers.log ("export %s=%s" %(var, directory))
-            self.__recreate_directory (directory)
-            os.environ [var] = directory
+        self._dirs = {
+            "XDG_DATA_HOME" : self.xdg_data_home(),
+            "XDG_CACHE_HOME": self.xdg_cache_home()
+        }
 
-        for directory in EXTRA_DIRS:
-            self.__recreate_directory (directory)
+        for var, directory in self._dirs.items():
+            os.makedirs (directory)
+            os.makedirs (os.path.join(directory, 'tracker'))
+            os.environ [var] = directory
 
         if ontodir:
-            helpers.log ("export %s=%s" % ("TRACKER_DB_ONTOLOGIES_DIR", ontodir))
             os.environ ["TRACKER_DB_ONTOLOGIES_DIR"] = ontodir
 
         for var, value in TEST_ENV_VARS.iteritems ():
-            helpers.log ("export %s=%s" %(var, value))
             os.environ [var] = value
 
         # Previous loop should have set DCONF_PROFILE to the test location
         if settings is not None:
             self._apply_settings(settings)
 
-        helpers.log ("[Conf] environment ready")
-
     def _apply_settings(self, settings):
         for schema_name, contents in settings.iteritems():
             dconf = DConfClient(schema_name)
@@ -106,29 +109,29 @@ class TrackerSystemAbstraction (object):
             raise UnableToBootException ("Unable to boot the store \n(" + str(e) + ")")
 
     def tracker_store_prepare_journal_replay (self):
-        db_location = os.path.join (TEST_ENV_DIRS ['XDG_CACHE_HOME'], "tracker", "meta.db")
+        db_location = os.path.join (self.xdg_cache_home(), "tracker", "meta.db")
         os.unlink (db_location)
 
-        lockfile = os.path.join (TEST_ENV_DIRS ['XDG_DATA_HOME'], "tracker", "data", ".ismeta.running")
+        lockfile = os.path.join (self.xdg_data_home(), "tracker", "data", ".ismeta.running")
         f = open (lockfile, 'w')
         f.write (" ")
         f.close ()
 
     def tracker_store_corrupt_dbs (self):
         for filename in ["meta.db", "meta.db-wal"]:
-            db_path = os.path.join (TEST_ENV_DIRS ['XDG_CACHE_HOME'], "tracker", filename)
+            db_path = os.path.join (self.xdg_cache_home(), "tracker", filename)
             f = open (db_path, "w")
             for i in range (0, 100):
                 f.write ("Some stupid content... hohohoho, not a sqlite file anymore!\n")
             f.close ()
 
     def tracker_store_remove_journal (self):
-        db_location = os.path.join (TEST_ENV_DIRS ['XDG_DATA_HOME'], "tracker", "data")
+        db_location = os.path.join (self.xdg_data_home(), "tracker", "data")
         shutil.rmtree (db_location)
         os.mkdir (db_location)
 
     def tracker_store_remove_dbs (self):
-        db_location = os.path.join (TEST_ENV_DIRS ['XDG_CACHE_HOME'], "tracker")
+        db_location = os.path.join (self.xdg_cache_home(), "tracker")
         shutil.rmtree (db_location)
         os.mkdir (db_location)
 
@@ -184,7 +187,23 @@ class TrackerSystemAbstraction (object):
         # This will stop all miner-fs, store and writeback
         self.tracker_writeback_testing_stop ()
 
-    def __recreate_directory (self, directory):
-        if (os.path.exists (directory)):
-            shutil.rmtree (directory)
-        os.makedirs (directory)
+    def finish (self):
+        """
+        Stop all running processes and remove all test data.
+        """
+
+        if self.writeback:
+            self.writeback.stop ()
+
+        if self.extractor:
+            self.extractor.stop ()
+
+        if self.miner_fs:
+            self.miner_fs.stop ()
+
+        if self.store:
+            self.store.stop ()
+
+        for path in self._dirs.values():
+            shutil.rmtree(path)
+        os.rmdir(self._basedir)
diff --git a/tests/functional-tests/common/utils/writebacktest.py 
b/tests/functional-tests/common/utils/writebacktest.py
index 674e0febf..c04573bee 100644
--- a/tests/functional-tests/common/utils/writebacktest.py
+++ b/tests/functional-tests/common/utils/writebacktest.py
@@ -34,24 +34,6 @@ TEST_FILE_PNG = "writeback-test-4.png"
 
 NFO_IMAGE = 'http://www.semanticdesktop.org/ontologies/2007/03/22/nfo#Image'
 
-WRITEBACK_TMP_DIR = os.path.join (cfg.TEST_MONITORED_TMP_DIR, "writeback")
-
-index_dirs = [WRITEBACK_TMP_DIR]
-CONF_OPTIONS = {
-    cfg.DCONF_MINER_SCHEMA: {
-        'index-recursive-directories': GLib.Variant.new_strv(index_dirs),
-        'index-single-directories': GLib.Variant.new_strv([]),
-        'index-optical-discs': GLib.Variant.new_boolean(False),
-        'index-removable-devices': GLib.Variant.new_boolean(False),
-    },
-    'org.freedesktop.Tracker.Store': {
-        'graphupdated-delay': GLib.Variant.new_int32(100)
-    }
-}
-
-
-def uri (filename):
-    return "file://" + os.path.join (WRITEBACK_TMP_DIR, filename)
 
 class CommonTrackerWritebackTest (ut.TestCase):
     """
@@ -67,24 +49,32 @@ class CommonTrackerWritebackTest (ut.TestCase):
             datadir = os.path.join (cfg.DATADIR, "tracker-tests",
                                     "test-writeback-data")
 
-        if not os.path.exists(WRITEBACK_TMP_DIR):
-            os.makedirs(WRITEBACK_TMP_DIR)
-        else:
-            if not os.path.isdir(WRITEBACK_TMP_DIR):
-                raise Exception("%s exists already and is not a directory" % WRITEBACK_TMP_DIR)
-
         for testfile in [TEST_FILE_JPEG, TEST_FILE_PNG,TEST_FILE_TIFF]:
             origin = os.path.join (datadir, testfile)
-            log ("Copying %s -> %s" % (origin, WRITEBACK_TMP_DIR))
-            shutil.copy (origin, WRITEBACK_TMP_DIR)
+            log ("Copying %s -> %s" % (origin, self.workdir))
+            shutil.copy (origin, self.workdir)
 
 
     def setUp(self):
-        #print "Starting the daemon in test mode"
+        self.workdir = cfg.create_monitored_test_dir()
+
+        index_dirs = [self.workdir]
+
+        CONF_OPTIONS = {
+            cfg.DCONF_MINER_SCHEMA: {
+                'index-recursive-directories': GLib.Variant.new_strv(index_dirs),
+                'index-single-directories': GLib.Variant.new_strv([]),
+                'index-optical-discs': GLib.Variant.new_boolean(False),
+                'index-removable-devices': GLib.Variant.new_boolean(False),
+            },
+            'org.freedesktop.Tracker.Store': {
+                'graphupdated-delay': GLib.Variant.new_int32(100)
+            }
+        }
+
         self.__prepare_directories ()
-        
-        self.system = TrackerSystemAbstraction ()
 
+        self.system = TrackerSystemAbstraction ()
         self.system.tracker_writeback_testing_start (CONF_OPTIONS)
 
         def await_resource_extraction(url):
@@ -101,25 +91,25 @@ class CommonTrackerWritebackTest (ut.TestCase):
         self.tracker = self.system.store
         self.extractor = self.system.extractor
 
-        # Returns when ready
-        log ("Ready to go!")
-
     def tearDown (self):
-        #print "Stopping the daemon in test mode (Doing nothing now)"
-        self.system.tracker_writeback_testing_stop ()
-        log ("Test finished")
+        self.system.finish ()
+
+        for testfile in [TEST_FILE_JPEG, TEST_FILE_PNG,TEST_FILE_TIFF]:
+            os.remove(os.path.join(self.workdir, testfile))
+
+        cfg.remove_monitored_test_dir(self.workdir)
+
+    def uri (self, filename):
+        return "file://" + os.path.join (self.workdir, filename)
 
-    @staticmethod
-    def get_test_filename_jpeg ():
-        return uri (TEST_FILE_JPEG)
+    def get_test_filename_jpeg (self):
+        return self.uri (TEST_FILE_JPEG)
 
-    @staticmethod
-    def get_test_filename_tiff ():
-        return uri (TEST_FILE_TIFF)
+    def get_test_filename_tiff (self):
+        return self.uri (TEST_FILE_TIFF)
 
-    @staticmethod
-    def get_test_filename_png ():
-        return uri (TEST_FILE_PNG)
+    def get_test_filename_png (self):
+        return self.uri (TEST_FILE_PNG)
 
     def get_mtime (self, filename):
         return os.stat(filename).st_mtime