diff --git a/spring-test/src/main/java/org/springframework/test/web/client/match/MockRestRequestMatchers.java b/spring-test/src/main/java/org/springframework/test/web/client/match/MockRestRequestMatchers.java
index 305126c65f..36670ba013 100644
--- a/spring-test/src/main/java/org/springframework/test/web/client/match/MockRestRequestMatchers.java
+++ b/spring-test/src/main/java/org/springframework/test/web/client/match/MockRestRequestMatchers.java
@@ -45,6 +45,7 @@ import static org.springframework.test.util.AssertionErrors.assertTrue;
  *
  * @author Craig Walls
  * @author Rossen Stoyanchev
+ * @author Sam Brannen
  * @since 3.2
  */
 public abstract class MockRestRequestMatchers {
@@ -132,7 +133,7 @@ public abstract class MockRestRequestMatchers {
 			MultiValueMap<String, String> params = getQueryParams(request);
 			assertValueCount("query param", name, params, expectedValues.length);
 			for (int i = 0 ; i < expectedValues.length; i++) {
-				assertEquals("Query param + [" + name + "]", expectedValues[i], params.get(name).get(i));
+				assertEquals("Query param [" + name + "]", expectedValues[i], params.get(name).get(i));
 			}
 		};
 	}
@@ -163,7 +164,7 @@ public abstract class MockRestRequestMatchers {
 			List<String> headerValues = request.getHeaders().get(name);
 			Assert.state(headerValues != null, "No header values");
 			for (int i = 0; i < matchers.length; i++) {
-				assertThat("Request header[" + name + "]", headerValues.get(i), matchers[i]);
+				assertThat("Request header [" + name + "]", headerValues.get(i), matchers[i]);
 			}
 		};
 	}
@@ -177,7 +178,7 @@ public abstract class MockRestRequestMatchers {
 			List<String> headerValues = request.getHeaders().get(name);
 			Assert.state(headerValues != null, "No header values");
 			for (int i = 0; i < expectedValues.length; i++) {
-				assertEquals("Request header  [" + name + "]",
+				assertEquals("Request header [" + name + "]",
 						expectedValues[i], headerValues.get(i));
 			}
 		};
diff --git a/spring-test/src/test/java/org/springframework/test/web/client/match/MockRestRequestMatchersTests.java b/spring-test/src/test/java/org/springframework/test/web/client/match/MockRestRequestMatchersTests.java
index c2d7f9c680..8477279342 100644
--- a/spring-test/src/test/java/org/springframework/test/web/client/match/MockRestRequestMatchersTests.java
+++ b/spring-test/src/test/java/org/springframework/test/web/client/match/MockRestRequestMatchersTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -25,13 +25,16 @@ import org.junit.Test;
 import org.springframework.http.HttpMethod;
 import org.springframework.mock.http.client.MockClientHttpRequest;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.containsString;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 /**
  * Unit tests for {@link MockRestRequestMatchers}.
  *
  * @author Craig Walls
  * @author Rossen Stoyanchev
+ * @author Sam Brannen
  */
 public class MockRestRequestMatchersTests {
 
@@ -52,11 +55,12 @@ public class MockRestRequestMatchersTests {
 		MockRestRequestMatchers.requestToUriTemplate("http://foo.com/{bar}", "bar").match(this.request);
 	}
 
-	@Test(expected = AssertionError.class)
+	@Test
 	public void requestToNoMatch() throws Exception {
 		this.request.setURI(new URI("http://foo.com/bar"));
 
-		MockRestRequestMatchers.requestTo("http://foo.com/wrong").match(this.request);
+		assertThrows(AssertionError.class,
+				() -> MockRestRequestMatchers.requestTo("http://foo.com/wrong").match(this.request));
 	}
 
 	@Test
@@ -73,11 +77,13 @@ public class MockRestRequestMatchersTests {
 		MockRestRequestMatchers.method(HttpMethod.GET).match(this.request);
 	}
 
-	@Test(expected = AssertionError.class)
+	@Test
 	public void methodNoMatch() throws Exception {
 		this.request.setMethod(HttpMethod.POST);
 
-		MockRestRequestMatchers.method(HttpMethod.GET).match(this.request);
+		AssertionError error = assertThrows(AssertionError.class,
+				() -> MockRestRequestMatchers.method(HttpMethod.GET).match(this.request));
+		assertThat(error.getMessage(), containsString("expected:<GET> but was:<POST>"));
 	}
 
 	@Test
@@ -87,16 +93,20 @@ public class MockRestRequestMatchersTests {
 		MockRestRequestMatchers.header("foo", "bar", "baz").match(this.request);
 	}
 
-	@Test(expected = AssertionError.class)
+	@Test
 	public void headerMissing() throws Exception {
-		MockRestRequestMatchers.header("foo", "bar").match(this.request);
+		AssertionError error = assertThrows(AssertionError.class,
+				() -> MockRestRequestMatchers.header("foo", "bar").match(this.request));
+		assertThat(error.getMessage(), containsString("was null"));
 	}
 
-	@Test(expected = AssertionError.class)
+	@Test
 	public void headerMissingValue() throws Exception {
 		this.request.getHeaders().put("foo", Arrays.asList("bar", "baz"));
 
-		MockRestRequestMatchers.header("foo", "bad").match(this.request);
+		AssertionError error = assertThrows(AssertionError.class,
+				() -> MockRestRequestMatchers.header("foo", "bad").match(this.request));
+		assertThat(error.getMessage(), containsString("expected:<bad> but was:<bar>"));
 	}
 
 	@Test
@@ -106,16 +116,20 @@ public class MockRestRequestMatchersTests {
 		MockRestRequestMatchers.header("foo", containsString("ba")).match(this.request);
 	}
 
-	@Test(expected = AssertionError.class)
+	@Test
 	public void headerContainsWithMissingHeader() throws Exception {
-		MockRestRequestMatchers.header("foo", containsString("baz")).match(this.request);
+		AssertionError error = assertThrows(AssertionError.class,
+				() -> MockRestRequestMatchers.header("foo", containsString("baz")).match(this.request));
+		assertThat(error.getMessage(), containsString("but was null"));
 	}
 
-	@Test(expected = AssertionError.class)
+	@Test
 	public void headerContainsWithMissingValue() throws Exception {
 		this.request.getHeaders().put("foo", Arrays.asList("bar", "baz"));
 
-		MockRestRequestMatchers.header("foo", containsString("bx")).match(this.request);
+		AssertionError error = assertThrows(AssertionError.class,
+				() -> MockRestRequestMatchers.header("foo", containsString("bx")).match(this.request));
+		assertThat(error.getMessage(), containsString("was \"bar\""));
 	}
 
 	@Test
@@ -125,46 +139,61 @@ public class MockRestRequestMatchersTests {
 		MockRestRequestMatchers.header("foo", "bar", "baz").match(this.request);
 	}
 
-	@Test(expected = AssertionError.class)
+	@Test
 	public void headersWithMissingHeader() throws Exception {
-		MockRestRequestMatchers.header("foo", "bar").match(this.request);
+		AssertionError error = assertThrows(AssertionError.class,
+				() -> MockRestRequestMatchers.header("foo", "bar").match(this.request));
+		assertThat(error.getMessage(), containsString("but was null"));
 	}
 
-	@Test(expected = AssertionError.class)
+	@Test
 	public void headersWithMissingValue() throws Exception {
 		this.request.getHeaders().put("foo", Collections.singletonList("bar"));
 
-		MockRestRequestMatchers.header("foo", "bar", "baz").match(this.request);
+		AssertionError error = assertThrows(AssertionError.class,
+				() -> MockRestRequestMatchers.header("foo", "bar", "baz").match(this.request));
+		assertThat(error.getMessage(), containsString("to have at least <2> values"));
 	}
 
 	@Test
 	public void queryParam() throws Exception {
 		this.request.setURI(new URI("http://foo.com/a?foo=bar&foo=baz"));
+
 		MockRestRequestMatchers.queryParam("foo", "bar", "baz").match(this.request);
 	}
 
-	@Test(expected = AssertionError.class)
+	@Test
 	public void queryParamMissing() throws Exception {
 		this.request.setURI(new URI("http://foo.com/a"));
-		MockRestRequestMatchers.queryParam("foo", "bar").match(this.request);
+
+		AssertionError error = assertThrows(AssertionError.class,
+				() -> MockRestRequestMatchers.queryParam("foo", "bar").match(this.request));
+		assertThat(error.getMessage(), containsString("but was null"));
 	}
 
-	@Test(expected = AssertionError.class)
+	@Test
 	public void queryParamMissingValue() throws Exception {
 		this.request.setURI(new URI("http://foo.com/a?foo=bar&foo=baz"));
-		MockRestRequestMatchers.queryParam("foo", "bad").match(this.request);
+
+		AssertionError error = assertThrows(AssertionError.class,
+				() -> MockRestRequestMatchers.queryParam("foo", "bad").match(this.request));
+		assertThat(error.getMessage(), containsString("expected:<bad> but was:<bar>"));
 	}
 
 	@Test
 	public void queryParamContains() throws Exception {
 		this.request.setURI(new URI("http://foo.com/a?foo=bar&foo=baz"));
+
 		MockRestRequestMatchers.queryParam("foo", containsString("ba")).match(this.request);
 	}
 
-	@Test(expected = AssertionError.class)
+	@Test
 	public void queryParamContainsWithMissingValue() throws Exception {
 		this.request.setURI(new URI("http://foo.com/a?foo=bar&foo=baz"));
-		MockRestRequestMatchers.queryParam("foo", containsString("bx")).match(this.request);
+
+		AssertionError error = assertThrows(AssertionError.class,
+				() -> MockRestRequestMatchers.queryParam("foo", containsString("bx")).match(this.request));
+		assertThat(error.getMessage(), containsString("was \"bar\""));
 	}
 
-}
\ No newline at end of file
+}