Added Tests for YANG model

Author: Sviatoslav Boichuk

src/sonic-yang-models/tests/files/sample_config_db.json

@@ -2623,6 +2623,14 @@
             "dpu1": {
                 "midplane_interface": "dpu1"
             }
+        },
+        "BANNER_MESSAGE": {
+            "global": {
+                "state": "enabled",
+                "login": "Some login message",
+                "motd": "Some message of the day",
+                "logout": "Some logout message"
+            }
         }
     },
     "SAMPLE_CONFIG_DB_UNKNOWN": {

src/sonic-yang-models/tests/yang_model_tests/tests/sonic-banner.json

@@ -0,0 +1,14 @@
+{
+    "BANNER_MESSAGE_TEST_STATE": {
+        "desc": "Configure Banner feature state."
+    },
+    "BANNER_MESSAGE_TEST_LOGIN" : {
+        "desc": "Banner login messages configuration in BANNER_MESSAGE table."
+    },
+    "BANNER_MESSAGE_TEST_MOTD" : {
+        "desc": "Banner MOTD messages configuration in BANNER_MESSAGE table."
+    },
+    "BANNER_MESSAGE_TEST_LOGOUT" : {
+        "desc": "Banner logout messages configuration in BANNER_MESSAGE table."
+    }
+}

src/sonic-yang-models/tests/yang_model_tests/tests_config/sonic-banner.json

@@ -0,0 +1,50 @@
+{
+    "BANNER_MESSAGE_TEST_STATE": {
+        "sonic-banner:sonic-banner": {
+            "sonic-banner:BANNER_MESSAGE": {
+                "global": {
+                    "state": "enabled",
+                    "login": "Some login message",
+                    "motd": "Some message of the day",
+                    "logout": "Some logout message"
+                }
+            }
+        }
+    },
+    "BANNER_MESSAGE_TEST_LOGIN": {
+        "sonic-banner:sonic-banner": {
+            "sonic-banner:BANNER_MESSAGE": {
+                "global": {
+                    "state": "enabled",
+                    "login": "Some login message",
+                    "motd": "Some message of the day",
+                    "logout": "Some logout message"
+                }
+            }
+        }
+    },
+    "BANNER_MESSAGE_TEST_MOTD": {
+        "sonic-banner:sonic-banner": {
+            "sonic-banner:BANNER_MESSAGE": {
+                "global": {
+                    "state": "enabled",
+                    "login": "Some login message",
+                    "motd": "Some message of the day",
+                    "logout": "Some logout message"
+                }
+            }
+        }
+    },
+    "BANNER_MESSAGE_TEST_LOGOUT": {
+        "sonic-banner:sonic-banner": {
+            "sonic-banner:BANNER_MESSAGE": {
+                "global": {
+                    "state": "enabled",
+                    "login": "Some login message",
+                    "motd": "Some message of the day",
+                    "logout": "Some logout message"
+                }
+            }
+        }
+    }
+}