Introduce queryParamCount() in MockRestRequestMatchers

[CToner3223]

Summary

Currently, MockRestServiceServer provides MockRestRequestMatchers.queryParam(String, Matcher) to validate parameter values. However, there is no built-in way to:

1. Assert the total number of query parameters to prevent extra, unexpected parameters.
2. Verify that each expected parameter is present with the correct value in a concise way.

Users must currently implement a custom RequestMatcher, adding unnecessary complexity.

Proposed Solution

Introduce a new MockRestRequestMatchers method:

public static RequestMatcher queryParamCount(int expectedCount)

• Ensures that the total number of query parameters matches expectedCount.
• Prevents extra, unexpected query parameters from sneaking in.

Example Usage

mockServer.expect(requestTo(startsWith("http://example.com/api")))
    .andExpect(queryParam("param1", "1"))  // Ensures param1 exists with value "1"
    .andExpect(queryParam("param2", "1"))  // Ensures param2 exists with value "1"
    .andExpect(queryParam("param3", "hello world"))  // Ensures param3 exists with value "hello world"
    .andExpect(queryParamCount(3))  // Ensures no extra params exist
    .andRespond(withSuccess());

Workarounds

Currently, users must manually parse the URI's query string inside a custom RequestMatcher, which introduces unnecessary boilerplate. Example:

mockServer.expect(request -> {
    URI uri = request.getURI();
    Map<String, List<String>> params = UriComponentsBuilder.fromUri(uri).build().getQueryParams();
    
    if (params.size() != 3) {
        throw new AssertionError("Expected 3 query parameters, but found " + params.size());
    }
    if (!params.containsKey("param1") || !params.get("param1").contains("1")) {
        throw new AssertionError("Missing or incorrect value for param1.");
    }
    if (!params.containsKey("param2") || !params.get("param2").contains("1")) {
        throw new AssertionError("Missing or incorrect value for param2.");
    }
    if (!params.containsKey("param3") || !params.get("param3").contains("hello world")) {
        throw new AssertionError("Missing or incorrect value for param3.");
    }
}).andRespond(withSuccess());

Benefit

Adding queryParamCount() would:

✅ Improve test readability and maintainability.
✅ Prevent silent failures due to extra or missing parameters.
✅ Reduce boilerplate when asserting both parameter existence and correctness.

Would this be a useful addition to MockRestRequestMatchers?

[sbrannen]

Hi @CToner3223,

Congratulations on submitting your first issue for the Spring Framework! 👍

Currently, MockRestServiceServer provides MockRestRequestMatchers.queryParamExists(String name) to check for the presence of a query parameter

Unless I'm overlooking something, MockRestRequestMatchers does not contain a queryParamExists(String) method. Are you perhaps referring to something else?

In any case, thanks for the proposal. We'll consider that within the team.

[CToner3223]

Ah your correct, not sure why I thought queryParamExists existed, it must be a custom matcher i've seen somewhere.

Thanks for the consideration, I've been writing quite a few tests lately that would benefit from this sort of built in matcher, so hopefully it gets the green light.

[sbrannen]

so hopefully it gets the green light.

It has received "the green light". 😉

[sbrannen]

This feature has been implemented in main for inclusion in 7.0 M4.

Though, feel free to try it out early in 7.0 snapshots.

[CToner3223]

Great news, thanks very much! Lighting fast turn around too!