Module builds now remember what module they reused for building.

There was a race condition, when 2 builds where build in the same time.
There was an issue that after one has finished the other reused the new build
for reuse and not the one it started with.

Ticket-ID: FACTORY-3862

Signed-off-by: Martin Curlej <mcurlej@redhat.com>

tests/test_utils/test_utils.py

@@ -1429,3 +1429,45 @@ class TestOfflineLocalBuilds:
             module_build = models.ModuleBuild.get_build_from_nsvc(
                 db.session, "platform", "y", 1, "000000")
             assert module_build
+
+
+class TestUtilsModuleReuse:
+
+    def setup_method(self, test_method):
+        init_data()
+
+    def teardown_method(self, test_method):
+        clean_database()
+
+    def test_get_reusable_module_when_reused_module_not_set(self):
+        module = models.ModuleBuild.query.filter_by(
+            name="nginx").order_by(models.ModuleBuild.id.desc()).first()
+        module.state = models.BUILD_STATES["build"]
+        db.session.commit()
+
+        assert not module.reused_module
+
+        reusable_module = module_build_service.utils.get_reusable_module(
+            db.session, module)
+
+        assert module.reused_module
+        assert reusable_module.id == module.reused_module_id
+
+    def test_get_reusable_module_when_reused_module_already_set(self):
+        modules = models.ModuleBuild.query.filter_by(
+            name="nginx").order_by(models.ModuleBuild.id.desc()).limit(2).all()
+        build_module = modules[0]
+        reused_module = modules[1]
+        build_module.state = models.BUILD_STATES["build"]
+        build_module.reused_module_id = reused_module.id
+        db.session.commit()
+
+        assert build_module.reused_module
+        assert reused_module == build_module.reused_module
+
+        reusable_module = module_build_service.utils.get_reusable_module(
+            db.session, build_module)
+
+        assert build_module.reused_module
+        assert reusable_module.id == build_module.reused_module_id
+        assert reusable_module.id == reused_module.id