Add missing reply schema and coverage tests (#12079)

The change in #12018 break the CI (fixed by #12083).
There are quite a few sentinel commands that are missing both test coverage and also schema.

PR added reply-schema to the following commands:
- sentinel debug
- sentinel info-cache
- sentinel pendding-scripts
- sentinel reset
- sentinel simulate-failure

Added some very basic tests for other sentinel commands, just so that they have some coverage.
- sentinel help
- sentinel masters
- sentinel myid
- sentinel sentinels
- sentinel slaves

These tests should be improved / replaced in a followup PR.

6 files changed, 121 insertions, 6 deletions

diff --git a/src/commands/sentinel-debug.json b/src/commands/sentinel-debug.json
index 186b1df9d..c671ec5e1 100644
--- a/src/commands/sentinel-debug.json
+++ b/src/commands/sentinel-debug.json
@@ -12,6 +12,21 @@
             "SENTINEL",
             "ONLY_SENTINEL"
         ],
+        "reply_schema": {
+            "oneOf": [
+                {
+                    "description": "The configuration update was successful.",
+                    "const": "OK"
+                },
+                {
+                    "description": "List of configurable time parameters and their values (milliseconds).",
+                    "type": "object",
+                    "additionalProperties": {
+                        "type": "string"
+                    }
+                }
+            ]
+        },
         "arguments": [
             {
                 "name": "data",
diff --git a/src/commands/sentinel-info-cache.json b/src/commands/sentinel-info-cache.json
index 29af975bc..af89f182e 100644
--- a/src/commands/sentinel-info-cache.json
+++ b/src/commands/sentinel-info-cache.json
@@ -12,6 +12,47 @@
             "SENTINEL",
             "ONLY_SENTINEL"
         ],
+        "reply_schema": {
+            "type": "array",
+            "description": "This is actually a map, the odd entries are a master name, and the even entries are the last cached INFO output from that master and all its replicas.",
+            "minItems": 0,
+            "maxItems": 4294967295,
+            "items": [
+                {
+                    "oneOf": [
+                        {
+                            "type": "string",
+                            "description": "The master name."
+                        },
+                        {
+                            "type": "array",
+                            "description": "This is an array of pairs, the odd entries are the INFO age, and the even entries are the cached INFO string. The first pair belong to the master and the rest are its replicas.",
+                            "minItems": 2,
+                            "maxItems": 2,
+                            "items": [
+                                {
+                                    "description": "The number of milliseconds since when the INFO was cached.",
+                                    "type": "integer"
+                                },
+                                {
+                                    "description": "The cached INFO string or null.",
+                                    "oneOf": [
+                                        {
+                                            "description": "The cached INFO string.",
+                                            "type": "string"
+                                        },
+                                        {
+                                            "description": "No cached INFO string.",
+                                            "type": "null"
+                                        }
+                                    ]
+                                }
+                            ]
+                        }
+                    ]
+                }
+            ]
+        },
         "arguments": [
             {
                 "name": "nodename",
diff --git a/src/commands/sentinel-pending-scripts.json b/src/commands/sentinel-pending-scripts.json
index 141343149..22dae4774 100644
--- a/src/commands/sentinel-pending-scripts.json
+++ b/src/commands/sentinel-pending-scripts.json
@@ -10,6 +10,43 @@
             "ADMIN",
             "SENTINEL",
             "ONLY_SENTINEL"
-        ]
+        ],
+        "reply_schema": {
+            "type": "array",
+            "description": "List of pending scripts.",
+            "items": {
+                "type": "object",
+                "additionalProperties": false,
+                "properties": {
+                    "argv": {
+                        "type": "array",
+                        "description": "Script arguments.",
+                        "items": {
+                            "type": "string"
+                        }
+                    },
+                    "flags": {
+                        "type": "string",
+                        "description": "Script flags."
+                    },
+                    "pid": {
+                        "type": "string",
+                        "description": "Script pid."
+                    },
+                    "run-time": {
+                        "type": "string",
+                        "description": "Script run-time."
+                    },
+                    "run-delay": {
+                        "type": "string",
+                        "description": "Script run-delay."
+                    },
+                    "retry-num": {
+                        "type": "string",
+                        "description": "Number of times we tried to execute the script."
+                    }
+                }
+            }
+        }
     }
 }
diff --git a/src/commands/sentinel-reset.json b/src/commands/sentinel-reset.json
index 14ccbd5a1..17b53a481 100644
--- a/src/commands/sentinel-reset.json
+++ b/src/commands/sentinel-reset.json
@@ -12,6 +12,10 @@
             "SENTINEL",
             "ONLY_SENTINEL"
         ],
+        "reply_schema": {
+            "type": "integer",
+            "description": "The number of masters that were reset."
+        },
         "arguments": [
             {
                 "name": "pattern",
diff --git a/src/commands/sentinel-simulate-failure.json b/src/commands/sentinel-simulate-failure.json
index 00aad668d..5031d44ae 100644
--- a/src/commands/sentinel-simulate-failure.json
+++ b/src/commands/sentinel-simulate-failure.json
@@ -11,6 +11,21 @@
             "SENTINEL",
             "ONLY_SENTINEL"
         ],
+        "reply_schema": {
+            "oneOf": [
+                {
+                    "description": "The simulated flag was set.",
+                    "const": "OK"
+                },
+                {
+                    "description": "Supported simulates flags. Returned in case `HELP` was used.",
+                    "type": "array",
+                    "items": {
+                        "type": "string"
+                    }
+                }
+            ]
+        },
         "arguments": [
             {
                 "name": "mode",
diff --git a/src/sentinel.c b/src/sentinel.c
index 03482fdd2..3d5c3861c 100644
--- a/src/sentinel.c
+++ b/src/sentinel.c
@@ -4071,11 +4071,14 @@ NULL
         }
 
         /* Reply format:
-         *   1.) master name
-         *   2.) 1.) info from master
-         *       2.) info from replica
-         *       ...
-         *   3.) other master name
+         *   1) master name
+         *   2) 1) 1) info cached ms
+         *         2) info from master
+         *      2) 1) info cached ms
+         *         2) info from replica1
+         *      ...
+         *   3) other master name
+         *      ...
          *   ...
          */
         addReplyArrayLen(c,dictSize(masters_local) * 2);