Introduce queryParamCount() in MockRestRequestMatchers

Closes gh-34703

Author: sbrannen

spring-test/src/main/java/org/springframework/test/web/client/match/MockRestRequestMatchers.java

@@ -19,6 +19,7 @@
 import java.net.URI;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import javax.xml.xpath.XPathExpressionException;
 
@@ -130,6 +131,7 @@ public static RequestMatcher requestTo(URI uri) {
 	 * @since 5.3.27
 	 * @see #queryParam(String, Matcher...)
 	 * @see #queryParam(String, String...)
+	 * @see #queryParamCount(int)
 	 */
 	public static RequestMatcher queryParamList(String name, Matcher<? super List<String>> matcher) {
 		return request -> {
@@ -158,6 +160,7 @@ public static RequestMatcher queryParamList(String name, Matcher<? super List<St
 	 * parameter value
 	 * @see #queryParamList(String, Matcher)
 	 * @see #queryParam(String, String...)
+	 * @see #queryParamCount(int)
 	 */
 	@SafeVarargs
 	@SuppressWarnings("NullAway") // Dataflow analysis limitation
@@ -187,6 +190,7 @@ public static RequestMatcher queryParam(String name, Matcher<? super String>...
 	 * parameter value
 	 * @see #queryParamList(String, Matcher)
 	 * @see #queryParam(String, Matcher...)
+	 * @see #queryParamCount(int)
 	 */
 	@SuppressWarnings("NullAway") // Dataflow analysis limitation
 	public static RequestMatcher queryParam(String name, String... expectedValues) {
@@ -199,6 +203,25 @@ public static RequestMatcher queryParam(String name, String... expectedValues) {
 		};
 	}
 
+	/**
+	 * Assert the number of query parameters present in the request.
+	 * @param expectedCount the number of expected query parameters
+	 * @since 7.0
+	 * @see #queryParamList(String, Matcher)
+	 * @see #queryParam(String, Matcher...)
+	 * @see #queryParam(String, String...)
+	 */
+	@SuppressWarnings("NullAway") // Dataflow analysis limitation
+	public static RequestMatcher queryParamCount(int expectedCount) {
+		return request -> {
+			Set<String> parameterNames = getQueryParams(request).keySet();
+			int actualCount = parameterNames.size();
+			if (expectedCount != actualCount) {
+				fail("Expected %d query parameter(s) but found %d: %s".formatted(expectedCount, actualCount, parameterNames));
+			}
+		};
+	}
+
 	private static MultiValueMap<String, String> getQueryParams(ClientHttpRequest request) {
 		return UriComponentsBuilder.fromUri(request.getURI()).build().getQueryParams();
 	}
@@ -359,7 +382,6 @@ public static XpathRequestMatchers xpath(String expression, Map<String, String>
 
 
 	private static void assertValueCount(String name, MultiValueMap<String, String> map, int count) {
-
 		List<String> values = map.get(name);
 		String message = "Expected query param <" + name + ">";
 		if (values == null) {
@@ -371,7 +393,6 @@ else if (count > values.size()) {
 	}
 
 	private static void assertValueCount(String name, HttpHeaders headers, int count) {
-
 		List<String> values = headers.get(name);
 		String message = "Expected header <" + name + ">";
 		if (values == null) {

spring-test/src/test/java/org/springframework/test/web/client/match/MockRestRequestMatchersTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -287,7 +287,6 @@ void queryParamContainsWithMissingValue() {
 			.withMessageContaining("was \"bar\"");
 	}
 
-
 	@Test
 	void queryParamListMissing() {
 		assertThatAssertionError()
@@ -353,6 +352,34 @@ void queryParamListDoesNotHideQueryParamWithSingleMatcher() throws IOException {
 						"but: was <[bar, baz]>");
 	}
 
+	@Test  // gh-34703
+	void queryParamCount() throws Exception {
+		this.request.setURI(URI.create("http://www.foo.example/a"));
+		MockRestRequestMatchers.queryParamCount(0).match(this.request);
+
+		this.request.setURI(URI.create("http://www.foo.example/a?"));
+		MockRestRequestMatchers.queryParamCount(0).match(this.request);
+
+		this.request.setURI(URI.create("http://www.foo.example/a?foo=1"));
+		MockRestRequestMatchers.queryParamCount(1).match(this.request);
+
+		this.request.setURI(URI.create("http://www.foo.example/a?foo=1&foo=2"));
+		MockRestRequestMatchers.queryParamCount(1).match(this.request);
+
+		this.request.setURI(URI.create("http://www.foo.example/a?foo=1&baz=2"));
+		MockRestRequestMatchers.queryParamCount(2).match(this.request);
+	}
+
+	@Test  // gh-34703
+	void queryParamCountMismatch() {
+		this.request.setURI(URI.create("http://www.foo.example/a?foo=1&baz=2"));
+
+		assertThatAssertionError()
+				.isThrownBy(() -> MockRestRequestMatchers.queryParamCount(1).match(this.request))
+				.withMessage("Expected 1 query parameter(s) but found 2: [foo, baz]");
+	}
+
+
 	private static ThrowableTypeAssert<AssertionError> assertThatAssertionError() {
 		return assertThatExceptionOfType(AssertionError.class);
 	}