[Specs] add case for constant query

.chronus/changes/fix-python-constant-query-new-2025-9-28-11-8-13.md

@@ -0,0 +1,7 @@
+---
+changeKind: feature
+packages:
+  - "@typespec/http-specs"
+---
+
+Add case for constant query

packages/http-specs/spec-summary.md

@@ -1264,6 +1264,12 @@ Second request path:
 /optional/foo
 ```
 
+### Parameters_Query_Constant_post
+
+- Endpoint: `post /parameters/query/constant`
+
+Expect to handle a constant value for query and mock api returns nothing
+
 ### Parameters_Spread_Alias_spreadAsRequestBody
 
 - Endpoint: `put /parameters/spread/alias/request-body`

packages/http-specs/specs/parameters/query/main.tsp

@@ -0,0 +1,22 @@
+import "@typespec/http";
+import "@typespec/spector";
+
+using Http;
+using Spector;
+
+@doc("Test for query parameter cases.")
+@scenarioService("/parameters/query")
+namespace Parameters.Query;
+
+@doc("Constant query parameter verification")
+@route("/constant")
+interface Constant {
+  /** post constant query value */
+  @scenario
+  @scenarioDoc("Expect to handle a constant value for query and mock api returns nothing")
+  @post
+  post(
+    @query
+    queryParam: "constantValue",
+  ): void;
+}

packages/http-specs/specs/parameters/query/mockapi.ts

@@ -0,0 +1,15 @@
+import { passOnSuccess, ScenarioMockApi } from "@typespec/spec-api";
+
+export const Scenarios: Record<string, ScenarioMockApi> = {};
+
+Scenarios.Parameters_Query_Constant_post = passOnSuccess({
+  uri: "/parameters/query/constant",
+  method: `post`,
+  request: {
+    query: { queryParam: "constantValue" },
+  },
+  response: {
+    status: 204,
+  },
+  kind: "MockApiDefinition",
+});