[GCU] Add Sample Unit Test for RDMA Headroom Pool Size Tuning

tests/generic_config_updater/files/feature_patch_application_test_failure.json

@@ -0,0 +1,35 @@
+{
+    "RDMA_SHARED_POOL_SIZE_CHANGE__FAILURE": {
+        "desc": "For RDMA shared pool size tuning- adjust both shared pool and headroom pool",
+        "current_config": {
+            "BUFFER_POOL": {
+                "ingress_lossless_pool": {
+                    "xoff": "4194112",
+		    "type": "ingress",
+		    "mode": "dynamic",
+		    "size": "10875072"
+                },
+                "egress_lossless_pool": {
+                    "type": "egress",
+		    "mode": "static",
+		    "size": "15982720"
+                },
+		"egress_lossy_pool": {
+                    "type": "egress",
+		    "mode": "dynamic",
+		    "size": "9243812"
+                }
+            }
+        },
+        "patch": [
+            {
+                "op": "replace",
+                "path": "/BUFFER_POOL/ingress_lossless_pool/xoff",
+                "value": "invalid_xoff"
+            }
+        ],
+        "expected_error_substrings": [
+            "Given patch will produce invalid config"
+        ]
+    }
+}

tests/generic_config_updater/files/feature_patch_application_test_success.json

@@ -0,0 +1,62 @@
+{
+    "RDMA_SHARED_POOL_SIZE_CHANGE__SUCCESS": {
+        "desc": "For RDMA shared pool size tuning- adjust both shared pool and headroom pool",
+        "current_config": {
+            "BUFFER_POOL": {
+                "ingress_lossless_pool": {
+                    "xoff": "4194112",
+		    "type": "ingress",
+		    "mode": "dynamic",
+		    "size": "10875072"
+                },
+                "egress_lossless_pool": {
+                    "type": "egress",
+		    "mode": "static",
+		    "size": "15982720"
+                },
+		"egress_lossy_pool": {
+                    "type": "egress",
+		    "mode": "dynamic",
+		    "size": "9243812"
+                }
+            }
+        },
+        "patch": [
+            {
+                "op": "replace",
+                "path": "/BUFFER_POOL/ingress_lossless_pool/xoff",
+                "value": "2155712"
+            },
+            {
+                "op": "replace",
+                "path": "/BUFFER_POOL/ingress_lossless_pool/size",
+                "value": "12913472"
+            },
+            {
+                "op": "replace",
+                "path": "/BUFFER_POOL/egress_lossy_pool/size",
+                "value": "5200000"
+            }
+        ],
+        "expected_config": {
+            "BUFFER_POOL": {
+                "ingress_lossless_pool": {
+                    "xoff": "2155712",
+		    "type": "ingress",
+		    "mode": "dynamic",
+		    "size": "12913472"
+                },
+                "egress_lossless_pool": {
+                    "type": "egress",
+		    "mode": "static",
+		    "size": "15982720"
+                },
+		"egress_lossy_pool": {
+                    "type": "egress",
+		    "mode": "dynamic",
+		    "size": "5200000"
+                }
+            }
+        }
+    }
+}

tests/generic_config_updater/gcu_feature_patch_application_test.py

@@ -0,0 +1,95 @@
+import jsonpatch
+import unittest
+from unittest.mock import MagicMock, Mock
+
+import generic_config_updater.patch_sorter as ps
+from .gutest_helpers import Files
+from generic_config_updater.gu_common import ConfigWrapper, PatchWrapper
+
+
+class TestFeaturePatchApplication(unittest.TestCase):
+    def setUp(self):
+        self.config_wrapper = ConfigWrapper()
+
+    def test_feature_patch_application_success(self):
+        # Format of the JSON file containing the test-cases:
+        #
+        # {
+        #     "<unique_name_for_the_test>":{
+        #         "desc":"<brief explanation of the test case>",
+        #         "current_config":<the running config to be modified>,
+        #         "patch":<the JsonPatch to apply>,
+        #         "expected_config":<the config after jsonpatch modification>
+        #     },
+        #     .
+        #     .
+        #     .
+        # }
+        data = Files.FEATURE_PATCH_APPLICATION_TEST_SUCCESS
+
+        for test_case_name in data:
+            with self.subTest(name=test_case_name):
+                self.run_single_success_case(data[test_case_name])
+
+    def test_feature_patch_application_failure(self):
+        # Fromat of the JSON file containing the test-cases:
+        #
+        # {
+        #     "<unique_name_for_the_test>":{
+        #         "desc":"<brief explanation of the test case>",
+        #         "current_config":<the running config to be modified>,
+        #         "patch":<the JsonPatch to apply>,
+        #         "expected_error_substrings":<error substrings expected in failure output>
+        #     },
+        #     .
+        #     .
+        #     .
+        # }
+        data = Files.FEATURE_PATCH_APPLICATION_TEST_FAILURE
+
+        for test_case_name in data:
+            with self.subTest(name=test_case_name):
+                self.run_single_failure_case(data[test_case_name])
+
+    def create_strict_patch_sorter(self, config):
+        config_wrapper = self.config_wrapper
+        config_wrapper.get_config_db_as_json = MagicMock(return_value=config)
+        patch_wrapper = PatchWrapper(config_wrapper)
+        return ps.StrictPatchSorter(config_wrapper, patch_wrapper)
+
+    def run_single_success_case(self, data):
+        current_config = data["current_config"]
+        expected_config = data["expected_config"]
+        patch = jsonpatch.JsonPatch(data["patch"])
+        sorter = self.create_strict_patch_sorter(current_config)
+        actual_changes = sorter.sort(patch)
+        target_config = patch.apply(current_config)
+        simulated_config = current_config
+
+        for change in actual_changes:
+            simulated_config = change.apply(simulated_config)
+            is_valid, error = self.config_wrapper.validate_config_db_config(simulated_config)
+            self.assertTrue(is_valid, f"Change will produce invalid config. Error: {error}")
+
+        self.assertEqual(target_config, simulated_config)
+        self.assertEqual(simulated_config, expected_config)
+
+    def run_single_failure_case(self, data):
+        current_config = data["current_config"]
+        patch = jsonpatch.JsonPatch(data["patch"])
+        expected_error_substrings = data["expected_error_substrings"]
+
+        try:
+            sorter = self.create_strict_patch_sorter(current_config)
+            sorter.sort(patch)
+            self.fail("An exception was supposed to be thrown")
+        except Exception as ex:
+            notfound_substrings = []
+            error = str(ex)
+
+            for substring in expected_error_substrings:
+                if substring not in error:
+                    notfound_substrings.append(substring)
+
+            if notfound_substrings:
+                self.fail(f"Did not find the expected substrings {notfound_substrings} in the error: '{error}'")