added msearch template tests

Signed-off-by: Tokesh <[email protected]>

CHANGELOG.md

@@ -24,6 +24,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Added missing `status` to `/_search/template` response ([#702](https://github.com/opensearch-project/opensearch-api-specification/pull/702))
 - Added `_type` to `rank_eval` API specs ([#704](https://github.com/opensearch-project/opensearch-api-specification/pull/704))
 - Added request body to `_search_shards` API specs ([#709](https://github.com/opensearch-project/opensearch-api-specification/pull/709))
+- Added string type in additionalProperties to `msearch template` ([#x](https://github.com/opensearch-project/opensearch-api-specification/pull/x))
 
 ### Removed
 - Removed unsupported `_common.mapping:SourceField`'s `mode` field and associated `_common.mapping:SourceFieldMode` enum ([#652](https://github.com/opensearch-project/opensearch-api-specification/pull/652))

spec/schemas/_core.msearch_template.yaml

@@ -25,7 +25,9 @@ components:
             The value is the variable value.
           type: object
           additionalProperties:
-            type: object
+            oneOf:
+              - type: string
+              - type: object
         profile:
           description: When `true`, provides a profile for the query execution.
           type: boolean

tests/default/indices/msearch_template.yaml

@@ -0,0 +1,51 @@
+$schema: ../../../json_schemas/test_story.schema.yaml
+
+description: Test _termvectors and _msearch/template APIs.
+prologues:  
+  - path: /_bulk
+    method: POST
+    parameters:
+      refresh: true
+    request:
+      content_type: application/x-ndjson
+      payload:
+        - {create: {_index: books, _id: book1}}
+        - {author: "Harper Lee", title: "To Kill a Mockingbird", year: 1960}
+        - {create: {_index: books, _id: book2}}
+        - {author: "Elizabeth Rudnick", title: "Beauty and the Beast", year: 1991}
+        - {create: {_index: books, _id: book3}}
+        - {author: "George Orwell", title: "1984", year: 1949}
+epilogues:
+  - path: /books
+    method: DELETE
+    status: [200, 404]
+
+chapters:
+  - synopsis: Perform a multi-search template query using a GET request.
+    path: /{index}/_msearch/template
+    parameters:
+      index: books
+    method: GET
+    request:
+      content_type: application/x-ndjson
+      payload:
+        - {index: books}
+        - {source: '{"query": {"match": {"title": "{{title}}"}}}', params: {title: "Mockingbird"}}
+        - {index: books}
+        - {source: '{"query": {"match": {"title": "{{title}}"}}}', params: {title: "Beast"}}
+    response:
+      status: 200
+  - synopsis: Perform a multi-search template query using a POST request.
+    path: /{index}/_msearch/template
+    parameters:
+      index: books
+    method: POST
+    request:
+      content_type: application/x-ndjson
+      payload:
+        - {index: books}
+        - {source: '{"query": {"match": {"title": "{{title}}"}}}', params: {title: "1984"}}
+        - {index: books}
+        - {source: '{"query": {"match": {"author": "{{author}}"}}}', params: {author: "Harper Lee"}}
+    response:
+      status: 200