diff --git a/tests/staged_data/platform.yaml b/tests/staged_data/platform.yaml
index 4d364f2a..1b878c92 100644
--- a/tests/staged_data/platform.yaml
+++ b/tests/staged_data/platform.yaml
@@ -24,3 +24,4 @@ data:
       requires: {}
       mse: true
       koji_tag: module-f28-build
+      koji_side_tag_format: module-f28-{side_tag}-build
diff --git a/tests/test_resolver/test_db.py b/tests/test_resolver/test_db.py
index 979fe266..1a82b8ef 100644
--- a/tests/test_resolver/test_db.py
+++ b/tests/test_resolver/test_db.py
@@ -99,6 +99,33 @@ class TestDBModule:
             "testmodule", "master", "20170109091357", "78e4a6fd").keys()
         assert set(result) == expected
 
+    @pytest.mark.parametrize("missing_format", [False, True])
+    def test_get_module_build_dependencies_side_tag(
+            self, missing_format, reuse_component_init_data):
+        """
+        Test that we get the correct base module tag when a side tag is specified
+        """
+        platform = models.ModuleBuild.get_by_id(db_session, 1)
+        module = models.ModuleBuild.get_by_id(db_session, 2)
+        mmd = module.mmd()
+        xmd = mmd.get_xmd()
+        side_tag = "SIDETAG"
+        expected = {"module-f28-SIDETAG-build"}
+        xmd["mbs"]["side_tag"] = side_tag
+        mmd.set_xmd(xmd)
+        if missing_format:
+            # remove koji_tag_format from our platform
+            platform_mmd = platform.mmd()
+            platform_xmd = platform_mmd.get_xmd()
+            del platform_xmd["mbs"]["koji_side_tag_format"]
+            platform_mmd.set_xmd(platform_xmd)
+            platform.modulemd = mmd_to_str(mmd)
+            db_session.commit()
+            expected = {"module-f28-build"}
+        resolver = mbs_resolver.GenericResolver.create(db_session, conf, backend="db")
+        result = resolver.get_module_build_dependencies(mmd=mmd).keys()
+        assert set(result) == expected
+
     def test_get_module_build_dependencies_recursive(self, reuse_component_init_data):
         """
         Tests that the buildrequires are returned when it is two layers deep
diff --git a/tests/test_web/test_submit.py b/tests/test_web/test_submit.py
index 8a75bf53..633b8160 100644
--- a/tests/test_web/test_submit.py
+++ b/tests/test_web/test_submit.py
@@ -17,7 +17,7 @@ from module_build_service.common.utils import (mmd_to_str, load_mmd,
 from module_build_service.scheduler.db_session import db_session
 from module_build_service.web.submit import (
     get_prefixed_version, submit_module_build, submit_module_build_from_yaml,
-    process_module_context_configuration
+    process_module_context_configuration, _apply_side_tag,
 )
 from tests import (
     scheduler_init_data,
@@ -218,6 +218,53 @@ class TestProcessModuleContextConfiguration:
             assert stream.is_static_context()
 
 
+class TestApplySideTag:
+    def get_mmd(self):
+        yaml_str = """
+document: modulemd
+version: 2
+data:
+    name: app
+    stream: test
+    summary: "A test module"
+    description: >
+        "A test module stream"
+    license:
+        module: [ MIT ]
+    dependencies:
+        - buildrequires:
+            platform: []
+            gtk: []
+          requires:
+            platform: []
+            gtk: []
+        """
+        return load_mmd(yaml_str)
+
+    def test_apply_side_tag(self):
+        """
+        Test that the side tag option is correctly added into the xmd
+        """
+        mmd = self.get_mmd()
+        side_tag = "SIDETAG"
+        _apply_side_tag(mmd, {"side_tag": side_tag})
+
+        xmd = mmd.get_xmd()
+        assert xmd["mbs"]["side_tag"] == side_tag
+
+    def test_apply_side_tag_no_option(self):
+        """
+        Test that the xmd is unchanged when option not given
+        """
+        mmd = self.get_mmd()
+        xmd_orig = mmd.get_xmd()
+        _apply_side_tag(mmd, {})
+
+        xmd = mmd.get_xmd()
+        assert xmd == xmd_orig
+        assert "side_tag" not in xmd.get("mbs", {})
+
+
 @pytest.mark.usefixtures("reuse_component_init_data")
 class TestUtilsComponentReuse:
     @mock.patch("module_build_service.web.submit.submit_module_build")