diff --git a/spring-test/src/main/java/org/springframework/mock/http/client/reactive/MockClientHttpResponse.java b/spring-test/src/main/java/org/springframework/mock/http/client/reactive/MockClientHttpResponse.java
index 528dd2b2b6..9385899bff 100644
--- a/spring-test/src/main/java/org/springframework/mock/http/client/reactive/MockClientHttpResponse.java
+++ b/spring-test/src/main/java/org/springframework/mock/http/client/reactive/MockClientHttpResponse.java
@@ -64,7 +64,7 @@ public class MockClientHttpResponse implements ClientHttpResponse {
 	}
 
 	public MockClientHttpResponse(int status) {
-		Assert.isTrue(status >= 100 && status < 600, "Status must be between 1xx and 5xx");
+		Assert.isTrue(status > 99 && status < 1000, "Status must be between 100 and 999");
 		this.status = status;
 	}
 
diff --git a/spring-test/src/main/java/org/springframework/test/web/reactive/server/ExchangeResult.java b/spring-test/src/main/java/org/springframework/test/web/reactive/server/ExchangeResult.java
index ba8f58bb12..f94b49965c 100644
--- a/spring-test/src/main/java/org/springframework/test/web/reactive/server/ExchangeResult.java
+++ b/spring-test/src/main/java/org/springframework/test/web/reactive/server/ExchangeResult.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -161,6 +161,15 @@ public class ExchangeResult {
 		return this.response.getStatusCode();
 	}
 
+	/**
+	 * Return the HTTP status code (potentially non-standard and not resolvable
+	 * through the {@link HttpStatus} enum) as an integer.
+	 * @since 5.1.10
+	 */
+	public int getRawStatusCode() {
+		return this.response.getRawStatusCode();
+	}
+
 	/**
 	 * Return the response headers received from the server.
 	 */
diff --git a/spring-test/src/main/java/org/springframework/test/web/reactive/server/StatusAssertions.java b/spring-test/src/main/java/org/springframework/test/web/reactive/server/StatusAssertions.java
index f6a91eecc2..cce9cb8f9a 100644
--- a/spring-test/src/main/java/org/springframework/test/web/reactive/server/StatusAssertions.java
+++ b/spring-test/src/main/java/org/springframework/test/web/reactive/server/StatusAssertions.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -55,7 +55,7 @@ public class StatusAssertions {
 	 * Assert the response status as an integer.
 	 */
 	public WebTestClient.ResponseSpec isEqualTo(int status) {
-		int actual = this.exchangeResult.getStatus().value();
+		int actual = this.exchangeResult.getRawStatusCode();
 		this.exchangeResult.assertWithDiagnostics(() -> AssertionErrors.assertEquals("Status", status, actual));
 		return this.responseSpec;
 	}
diff --git a/spring-test/src/test/java/org/springframework/test/web/reactive/server/StatusAssertionTests.java b/spring-test/src/test/java/org/springframework/test/web/reactive/server/StatusAssertionTests.java
index 7e77ee1757..5b6f1c459a 100644
--- a/spring-test/src/test/java/org/springframework/test/web/reactive/server/StatusAssertionTests.java
+++ b/spring-test/src/test/java/org/springframework/test/web/reactive/server/StatusAssertionTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -62,6 +62,11 @@ public class StatusAssertionTests {
 		}
 	}
 
+	@Test // gh-23630
+	public void isEqualToWithCustomStatus() {
+		statusAssertions(600).isEqualTo(600);
+	}
+
 	@Test
 	public void reasonEquals() {
 		StatusAssertions assertions = statusAssertions(HttpStatus.CONFLICT);
@@ -177,6 +182,10 @@ public class StatusAssertionTests {
 
 
 	private StatusAssertions statusAssertions(HttpStatus status) {
+		return statusAssertions(status.value());
+	}
+
+	private StatusAssertions statusAssertions(int status) {
 		MockClientHttpRequest request = new MockClientHttpRequest(HttpMethod.GET, URI.create("/"));
 		MockClientHttpResponse response = new MockClientHttpResponse(status);