Fixed /_index_template/_simulate*.

Signed-off-by: dblock <dblock@amazon.com>

spec/namespaces/indices.yaml

@@ -409,9 +409,7 @@ paths:
         url: https://opensearch.org/docs/latest
       parameters:
         - $ref: '#/components/parameters/indices.simulate_index_template::path.name'
-        - $ref: '#/components/parameters/indices.simulate_index_template::query.cause'
         - $ref: '#/components/parameters/indices.simulate_index_template::query.cluster_manager_timeout'
-        - $ref: '#/components/parameters/indices.simulate_index_template::query.create'
         - $ref: '#/components/parameters/indices.simulate_index_template::query.master_timeout'
       requestBody:
         $ref: '#/components/requestBodies/indices.simulate_index_template'
@@ -4867,34 +4865,13 @@ components:
       schema:
         $ref: '../schemas/_common.yaml#/components/schemas/Name'
       style: simple
-    indices.simulate_index_template::query.cause:
-      name: cause
-      in: query
-      description: User defined reason for dry-run creating the new template for simulation purposes.
-      schema:
-        type: string
-        default: 'false'
-        description: User defined reason for dry-run creating the new template for simulation purposes.
     indices.simulate_index_template::query.cluster_manager_timeout:
       name: cluster_manager_timeout
       in: query
       description: Operation timeout for connection to cluster-manager node.
       schema:
         $ref: '../schemas/_common.yaml#/components/schemas/Duration'
       x-version-added: '2.0'
-    indices.simulate_index_template::query.create:
-      in: query
-      name: create
-      description: |-
-        If `true`, the template passed in the body is only used if no existing
-        templates match the same index patterns. If `false`, the simulation uses
-        the template with the highest priority. Note that the template is not
-        permanently added or updated in either case; it is only used for the
-        simulation.
-      schema:
-        type: boolean
-        default: false
-      style: form
     indices.simulate_index_template::query.master_timeout:
       in: query
       name: master_timeout

spec/schemas/indices.simulate_template.yaml

@@ -31,5 +31,4 @@ components:
           $ref: 'indices._common.yaml#/components/schemas/IndexSettings'
       required:
         - aliases
-        - mappings
         - settings

tests/default/indices/index_template/simulate.yaml

@@ -0,0 +1,44 @@
+$schema: ../../../../json_schemas/test_story.schema.yaml
+
+description: Test index configuration that would be applied by a particular index template.
+epilogues:
+  - path: /_index_template/daily_logs
+    method: DELETE
+    status: [200, 404]
+prologues:
+  - path: /_index_template/daily_logs
+    method: POST
+    request:
+      payload:
+        index_patterns:
+          - 'logs*'
+        priority: 0
+        template:
+          mappings:
+            properties:
+              text:
+                type: text
+          settings:
+            number_of_shards: 2
+            number_of_replicas: 2
+chapters:
+  - synopsis: Simulate a template configuration.
+    path: /_index_template/_simulate
+    method: POST
+    parameters:
+      cause: Testing.
+      create: false
+    request:
+      payload:
+        index_patterns:
+          - 'logs*'
+        priority: 1
+        template:
+          settings:
+            number_of_shards: 2
+            number_of_replicas: 2       
+  - synopsis: Get the index configuration that would be applied by the `daily_logs` index template.
+    path: /_index_template/_simulate/{name}
+    method: POST
+    parameters:
+      name: daily_logs

tests/default/indices/index_template/simulate_index.yaml

@@ -0,0 +1,29 @@
+$schema: ../../../../json_schemas/test_story.schema.yaml
+
+description: Test index configuration that would be applied by a particular index template.
+prologues:
+  - path: /_index_template/daily_logs
+    method: POST
+    request:
+      payload:
+        index_patterns:
+          - 'logs*'
+        priority: 0
+        template:
+          mappings:
+            properties:
+              text:
+                type: text
+          settings:
+            number_of_shards: 2
+            number_of_replicas: 2
+epilogues:
+  - path: /_index_template/daily_logs
+    method: DELETE
+    status: [200, 404]
+chapters:
+  - synopsis: Simulate matching the `logs-today` name against the `logs*` index template.
+    path: /_index_template/_simulate_index/{name}
+    method: POST
+    parameters:
+      name: logs-today