tests: Make meson be aware of the single python unit tests

Scan for the unit tests in virtual-image suite and handle them individually

tests/meson.build

@@ -26,12 +26,35 @@ if get_option('introspection')
     envs.prepend('GI_TYPELIB_PATH', join_paths(meson.build_root(), 'libfprint'))
 
     if 'virtual_image' in drivers
-        test('virtual-image',
-            find_program('virtual-image.py'),
-            args: '--verbose',
-            env: envs,
-            depends: libfprint_typelib,
-        )
+        python3 = find_program('python3')
+        unittest_inspector = find_program('unittest_inspector.py')
+        base_args = files('virtual-image.py')
+        suite = []
+
+        r = run_command(unittest_inspector, files('virtual-image.py'))
+        unit_tests = r.stdout().strip().split('\n')
+
+        if r.returncode() == 0 and unit_tests.length() > 0
+            suite += 'virtual-image'
+        else
+            unit_tests = ['virtual-image']
+        endif
+
+        foreach ut: unit_tests
+            ut_suite = suite
+            ut_args = base_args
+            if unit_tests.length() > 1
+                ut_args += ut
+                ut_suite += ut.split('.')[0]
+            endif
+            test(ut,
+                python3,
+                args: ut_args,
+                suite: ut_suite,
+                depends: libfprint_typelib,
+                env: envs,
+            )
+        endforeach
     else
         test('virtual-image',
             find_program('sh'),

tests/unittest_inspector.py

@@ -0,0 +1,46 @@
+#! /usr/bin/env python3
+# Copyright © 2020, Canonical Ltd
+#
+# 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 2.1 of the License, or (at your option) any later version.
+#
+# This program 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/>.
+# Authors:
+#       Marco Trevisan <marco.trevisan@canonical.com>
+
+import argparse
+import importlib.util
+import inspect
+import os
+import unittest
+
+def list_tests(module):
+    tests = []
+    for name, obj in inspect.getmembers(module):
+        if inspect.isclass(obj) and issubclass(obj, unittest.TestCase):
+            cases = unittest.defaultTestLoader.getTestCaseNames(obj)
+            tests += [ (obj, '{}.{}'.format(name, t)) for t in cases ]
+    return tests
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument('unittest_source', type=argparse.FileType('r'))
+
+    args = parser.parse_args()
+    source_path = args.unittest_source.name
+    spec = importlib.util.spec_from_file_location(
+        os.path.basename(source_path), source_path)
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+
+    for machine, human in list_tests(module):
+        print(human)

tests/virtual-image.py

@@ -345,6 +345,6 @@ class VirtualImage(unittest.TestCase):
             ctx.iteration(True)
         assert(not self._verify_match)
 
-# avoid writing to stderr
-unittest.main(testRunner=unittest.TextTestRunner(stream=sys.stdout, verbosity=2))
-
+if __name__ == '__main__':
+    # avoid writing to stderr
+    unittest.main(testRunner=unittest.TextTestRunner(stream=sys.stdout, verbosity=2))