Add tests

tests/test_lint_upgrade_proposals.py

@@ -112,6 +112,38 @@ def does_not_raise():
 1111-12:
   python: 3.8.6
 """
+
+VALID_UPGRADE_PROPOSALS_NESTED_ONE_LEVEL = """
+1111-12:
+  wheel:
+    py38: 0.40.0
+    py311: 0.40.0
+"""
+
+VALID_UPGRADE_PROPOSALS_NESTED_TWO_LEVEL = """
+1111-12:
+  wheel:
+    rhel7:
+        py38: 0.40.0
+    rhel8:
+        py38: 0.40.0
+        py311: 0.40.0
+"""
+
+VALID_UPGRADE_PROPOSALS_MULTI_NESTED = """
+1111-12:
+  python: 3.8.6
+  setuptools:
+      py38: 68.0.0
+      py311: 68.0.0
+  wheel:
+    rhel7:
+        py38: 0.40.0
+    rhel8:
+        py38: 0.40.0
+        py311: 0.40.0
+"""
+
 INVALID_UPGRADE_PROPOSALS_DUPLICATE_PACKAGES = """
 1111-11:
 1111-12:
@@ -217,6 +249,24 @@ def does_not_raise():
             ),
             id="repository_file_missing_package_version",
         ),
+        pytest.param(
+            VALID_UPGRADE_PROPOSALS_NESTED_ONE_LEVEL,
+            VALID_REPOSITORY,
+            does_not_raise(),
+            id="one_level_nested_package_versions_in_upgrade_proposals",
+        ),
+        pytest.param(
+            VALID_UPGRADE_PROPOSALS_NESTED_TWO_LEVEL,
+            VALID_REPOSITORY,
+            does_not_raise(),
+            id="two_level_nested_package_versions_in_upgrade_proposals",
+        ),
+        pytest.param(
+            VALID_UPGRADE_PROPOSALS_MULTI_NESTED,
+            VALID_REPOSITORY,
+            does_not_raise(),
+            id="combined_level_nested_package_versions_in_upgrade_proposals",
+        ),
         pytest.param(
             INVALID_UPGRADE_PROPOSALS_DUPLICATE_PACKAGES,
             VALID_REPOSITORY,