Hamcrest methods in WebTestClient

Issue: SPR-16729

spring-test/src/main/java/org/springframework/test/web/reactive/server/DefaultWebTestClient.java

@@ -18,6 +18,7 @@ package org.springframework.test.web.reactive.server;
 
 import java.net.URI;
 import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 import java.time.Duration;
 import java.time.ZonedDateTime;
 import java.util.Arrays;
@@ -27,8 +28,9 @@ import java.util.Optional;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.Consumer;
 import java.util.function.Function;
-import javax.xml.xpath.XPathExpressionException;
 
+import org.hamcrest.Matcher;
+import org.hamcrest.MatcherAssert;
 import org.reactivestreams.Publisher;
 import reactor.core.publisher.Flux;
 
@@ -40,6 +42,7 @@ import org.springframework.http.MediaType;
 import org.springframework.http.client.reactive.ClientHttpConnector;
 import org.springframework.http.client.reactive.ClientHttpRequest;
 import org.springframework.lang.Nullable;
+import org.springframework.test.util.AssertionErrors;
 import org.springframework.test.util.JsonExpectationsHelper;
 import org.springframework.test.util.XmlExpectationsHelper;
 import org.springframework.util.Assert;
@@ -50,10 +53,6 @@ import org.springframework.web.reactive.function.client.ClientResponse;
 import org.springframework.web.reactive.function.client.WebClient;
 import org.springframework.web.util.UriBuilder;
 
-import static java.nio.charset.StandardCharsets.UTF_8;
-import static org.springframework.test.util.AssertionErrors.assertEquals;
-import static org.springframework.test.util.AssertionErrors.assertTrue;
-
 /**
  * Default implementation of {@link WebTestClient}.
  *
@@ -384,7 +383,22 @@ class DefaultWebTestClient implements WebTestClient {
 		@Override
 		public <T extends S> T isEqualTo(B expected) {
 			this.result.assertWithDiagnostics(() ->
-					assertEquals("Response body", expected, this.result.getResponseBody()));
+					AssertionErrors.assertEquals("Response body", expected, this.result.getResponseBody()));
+			return self();
+		}
+
+		@Override
+		public <T extends S> T value(Matcher<B> matcher) {
+			this.result.assertWithDiagnostics(() -> MatcherAssert.assertThat(this.result.getResponseBody(), matcher));
+			return self();
+		}
+
+		@Override
+		public <T extends S, R> T value(Function<B, R> bodyMapper, Matcher<R> matcher) {
+			this.result.assertWithDiagnostics(() -> {
+				B body = this.result.getResponseBody();
+				MatcherAssert.assertThat(bodyMapper.apply(body), matcher);
+			});
 			return self();
 		}
 
@@ -417,7 +431,8 @@ class DefaultWebTestClient implements WebTestClient {
 		public ListBodySpec<E> hasSize(int size) {
 			List<E> actual = getResult().getResponseBody();
 			String message = "Response body does not contain " + size + " elements";
-			getResult().assertWithDiagnostics(() -> assertEquals(message, size, (actual != null ? actual.size() : 0)));
+			getResult().assertWithDiagnostics(() ->
+					AssertionErrors.assertEquals(message, size, (actual != null ? actual.size() : 0)));
 			return this;
 		}
 
@@ -427,7 +442,8 @@ class DefaultWebTestClient implements WebTestClient {
 			List<E> expected = Arrays.asList(elements);
 			List<E> actual = getResult().getResponseBody();
 			String message = "Response body does not contain " + expected;
-			getResult().assertWithDiagnostics(() -> assertTrue(message, (actual != null && actual.containsAll(expected))));
+			getResult().assertWithDiagnostics(() ->
+					AssertionErrors.assertTrue(message, (actual != null && actual.containsAll(expected))));
 			return this;
 		}
 
@@ -437,7 +453,8 @@ class DefaultWebTestClient implements WebTestClient {
 			List<E> expected = Arrays.asList(elements);
 			List<E> actual = getResult().getResponseBody();
 			String message = "Response body should not have contained " + expected;
-			getResult().assertWithDiagnostics(() -> assertTrue(message, (actual == null || !actual.containsAll(expected))));
+			getResult().assertWithDiagnostics(() ->
+					AssertionErrors.assertTrue(message, (actual == null || !actual.containsAll(expected))));
 			return this;
 		}
 
@@ -461,7 +478,8 @@ class DefaultWebTestClient implements WebTestClient {
 
 		@Override
 		public EntityExchangeResult<Void> isEmpty() {
-			this.result.assertWithDiagnostics(() -> assertTrue("Expected empty body", this.isEmpty));
+			this.result.assertWithDiagnostics(() ->
+					AssertionErrors.assertTrue("Expected empty body", this.isEmpty));
 			return new EntityExchangeResult<>(this.result, null);
 		}
 
@@ -506,8 +524,8 @@ class DefaultWebTestClient implements WebTestClient {
 			if (body == null || body.length == 0) {
 				return "";
 			}
-			MediaType mediaType = this.result.getResponseHeaders().getContentType();
+			Charset charset = Optional.ofNullable(this.result.getResponseHeaders().getContentType())
-			Charset charset = Optional.ofNullable(mediaType).map(MimeType::getCharset).orElse(UTF_8);
+					.map(MimeType::getCharset).orElse(StandardCharsets.UTF_8);
 			return new String(body, charset);
 		}
 

spring-test/src/main/java/org/springframework/test/web/reactive/server/HeaderAssertions.java

@@ -17,17 +17,16 @@
 package org.springframework.test.web.reactive.server;
 
 import java.util.Arrays;
-import java.util.regex.Pattern;
+
+import org.hamcrest.Matcher;
+import org.hamcrest.MatcherAssert;
 
 import org.springframework.http.CacheControl;
 import org.springframework.http.ContentDisposition;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.MediaType;
 import org.springframework.lang.Nullable;
-
+import org.springframework.test.util.AssertionErrors;
-import static org.springframework.test.util.AssertionErrors.assertEquals;
-import static org.springframework.test.util.AssertionErrors.assertTrue;
-import static org.springframework.test.util.AssertionErrors.fail;
 
 /**
  * Assertions on headers of the response.
@@ -59,20 +58,35 @@ public class HeaderAssertions {
 	}
 
 	/**
-	 * Expect a header with the given name whose first value matches the
+	 * Match the primary value of the response header with a regex.
-	 * provided regex pattern.
 	 * @param name the header name
-	 * @param pattern the String pattern to pass to {@link Pattern#compile(String)}
+	 * @param pattern the regex pattern
 	 */
 	public WebTestClient.ResponseSpec valueMatches(String name, String pattern) {
+		String value = getRequiredValue(name);
+		String message = getMessage(name) + "=[" + value + "] does not match [" + pattern + "]";
+		this.exchangeResult.assertWithDiagnostics(() -> AssertionErrors.assertTrue(message, value.matches(pattern)));
+		return this.responseSpec;
+	}
+
+	/**
+	 * Assert the primary value of the response header with a {@link Matcher}.
+	 * @param name the header name
+	 * @param matcher the matcher to sue
+	 * @since 5.1
+	 */
+	public WebTestClient.ResponseSpec value(String name, Matcher<? super String> matcher) {
+		String value = getRequiredValue(name);
+		this.exchangeResult.assertWithDiagnostics(() -> MatcherAssert.assertThat(value, matcher));
+		return this.responseSpec;
+	}
+
+	private String getRequiredValue(String name) {
 		String value = getHeaders().getFirst(name);
 		if (value == null) {
-			fail(getMessage(name) + " not found");
+			AssertionErrors.fail(getMessage(name) + " not found");
 		}
-		boolean match = Pattern.compile(pattern).matcher(value).matches();
+		return value;
-		String message = getMessage(name) + "=[" + value + "] does not match [" + pattern + "]";
-		this.exchangeResult.assertWithDiagnostics(() -> assertTrue(message, match));
-		return this.responseSpec;
 	}
 
 	/**
@@ -82,7 +96,7 @@ public class HeaderAssertions {
 	public WebTestClient.ResponseSpec exists(String name) {
 		if (!getHeaders().containsKey(name)) {
 			String message = getMessage(name) + " does not exist";
-			this.exchangeResult.assertWithDiagnostics(() -> fail(message));
+			this.exchangeResult.assertWithDiagnostics(() -> AssertionErrors.fail(message));
 		}
 		return this.responseSpec;
 	}
@@ -93,7 +107,7 @@ public class HeaderAssertions {
 	public WebTestClient.ResponseSpec doesNotExist(String name) {
 		if (getHeaders().containsKey(name)) {
 			String message = getMessage(name) + " exists with value=[" + getHeaders().getFirst(name) + "]";
-			this.exchangeResult.assertWithDiagnostics(() -> fail(message));
+			this.exchangeResult.assertWithDiagnostics(() -> AssertionErrors.fail(message));
 		}
 		return this.responseSpec;
 	}
@@ -140,7 +154,7 @@ public class HeaderAssertions {
 		MediaType actual = getHeaders().getContentType();
 		String message = getMessage("Content-Type") + "=[" + actual + "] is not compatible with [" + mediaType + "]";
 		this.exchangeResult.assertWithDiagnostics(() ->
-				assertTrue(message, (actual != null && actual.isCompatibleWith(mediaType))));
+				AssertionErrors.assertTrue(message, (actual != null && actual.isCompatibleWith(mediaType))));
 		return this.responseSpec;
 	}
 
@@ -175,7 +189,10 @@ public class HeaderAssertions {
 	}
 
 	private WebTestClient.ResponseSpec assertHeader(String name, @Nullable Object expected, @Nullable Object actual) {
-		this.exchangeResult.assertWithDiagnostics(() -> assertEquals(getMessage(name), expected, actual));
+		this.exchangeResult.assertWithDiagnostics(() -> {
+			String message = getMessage(name);
+			AssertionErrors.assertEquals(message, expected, actual);
+		});
 		return this.responseSpec;
 	}
 

spring-test/src/main/java/org/springframework/test/web/reactive/server/JsonPathAssertions.java

@@ -16,6 +16,8 @@
 
 package org.springframework.test.web.reactive.server;
 
+import org.hamcrest.Matcher;
+
 import org.springframework.test.util.JsonPathExpectationsHelper;
 
 /**
@@ -132,4 +134,22 @@ public class JsonPathAssertions {
 		return this.bodySpec;
 	}
 
+	/**
+	 * Delegates to {@link JsonPathExpectationsHelper#assertValue(String, Matcher)}.
+	 * @since 5.1
+	 */
+	public <T> WebTestClient.BodyContentSpec value(Matcher<T> matcher) {
+		this.pathHelper.assertValue(this.content, matcher);
+		return this.bodySpec;
+	}
+
+	/**
+	 * Delegates to {@link JsonPathExpectationsHelper#assertValue(String, Matcher, Class)}.
+	 * @since 5.1
+	 */
+	public <T> WebTestClient.BodyContentSpec value(Matcher<T> matcher, Class<T> targetType) {
+		this.pathHelper.assertValue(this.content, matcher, targetType);
+		return this.bodySpec;
+	}
+
 }

spring-test/src/main/java/org/springframework/test/web/reactive/server/StatusAssertions.java

@@ -16,9 +16,11 @@
 
 package org.springframework.test.web.reactive.server;
 
-import org.springframework.http.HttpStatus;
+import org.hamcrest.Matcher;
+import org.hamcrest.MatcherAssert;
 
-import static org.springframework.test.util.AssertionErrors.assertEquals;
+import org.springframework.http.HttpStatus;
+import org.springframework.test.util.AssertionErrors;
 
 /**
  * Assertions on the response status.
@@ -52,7 +54,7 @@ public class StatusAssertions {
 	 */
 	public WebTestClient.ResponseSpec isEqualTo(int status) {
 		int actual = this.exchangeResult.getStatus().value();
-		this.exchangeResult.assertWithDiagnostics(() -> assertEquals("Status", status, actual));
+		this.exchangeResult.assertWithDiagnostics(() -> AssertionErrors.assertEquals("Status", status, actual));
 		return this.responseSpec;
 	}
 
@@ -155,7 +157,7 @@ public class StatusAssertions {
 	public WebTestClient.ResponseSpec reasonEquals(String reason) {
 		String actual = this.exchangeResult.getStatus().getReasonPhrase();
 		String message = "Response status reason";
-		this.exchangeResult.assertWithDiagnostics(() -> assertEquals(message, reason, actual));
+		this.exchangeResult.assertWithDiagnostics(() -> AssertionErrors.assertEquals(message, reason, actual));
 		return this.responseSpec;
 	}
 
@@ -195,17 +197,30 @@ public class StatusAssertions {
 		return assertSeriesAndReturn(expected);
 	}
 
+	/**
+	 * Match the response status value with a Hamcrest matcher.
+	 * @param matcher the matcher to use
+	 * @since 5.1
+	 */
+	public WebTestClient.ResponseSpec value(Matcher<Integer> matcher) {
+		int value = this.exchangeResult.getStatus().value();
+		this.exchangeResult.assertWithDiagnostics(() -> MatcherAssert.assertThat("Response status", value, matcher));
+		return this.responseSpec;
+	}
+
 
 	private WebTestClient.ResponseSpec assertStatusAndReturn(HttpStatus expected) {
 		HttpStatus actual = this.exchangeResult.getStatus();
-		this.exchangeResult.assertWithDiagnostics(() -> assertEquals("Status", expected, actual));
+		this.exchangeResult.assertWithDiagnostics(() -> AssertionErrors.assertEquals("Status", expected, actual));
 		return this.responseSpec;
 	}
 
 	private WebTestClient.ResponseSpec assertSeriesAndReturn(HttpStatus.Series expected) {
 		HttpStatus status = this.exchangeResult.getStatus();
-		this.exchangeResult.assertWithDiagnostics(() ->
+		this.exchangeResult.assertWithDiagnostics(() -> {
-				assertEquals("Range for response status value " + status, expected, status.series()));
+			String message = "Range for response status value " + status;
+			AssertionErrors.assertEquals(message, expected, status.series());
+		});
 		return this.responseSpec;
 	}
 

spring-test/src/main/java/org/springframework/test/web/reactive/server/WebTestClient.java

@@ -25,6 +25,7 @@ import java.util.Map;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
+import org.hamcrest.Matcher;
 import org.reactivestreams.Publisher;
 
 import org.springframework.context.ApplicationContext;
@@ -758,6 +759,19 @@ public interface WebTestClient {
 		 */
 		<T extends S> T isEqualTo(B expected);
 
+		/**
+		 * Assert the extracted body with a {@link Matcher}.
+		 * @since 5.1
+		 */
+		<T extends S> T value(Matcher<B> matcher);
+
+		/**
+		 * Transform the extracted the body with a function, e.g. extracting a
+		 * property, and assert the mapped value with a {@link Matcher}.
+		 * @since 5.1
+		 */
+		<T extends S, R> T value(Function<B, R> bodyMapper, Matcher<R> matcher);
+
 		/**
 		 * Assert the exchange result with the given {@link Consumer}.
 		 */
@@ -851,8 +865,8 @@ public interface WebTestClient {
 		 * formatting specifiers as defined in {@link String#format}.
 		 * @param expression the XPath expression
 		 * @param args arguments to parameterize the expression
-		 * @see #xpath(String, Map, Object...)
 		 * @since 5.1
+		 * @see #xpath(String, Map, Object...)
 		 */
 		default XpathAssertions xpath(String expression, Object... args){
 			return xpath(expression, null, args);

spring-test/src/main/java/org/springframework/test/web/reactive/server/XpathAssertions.java

@@ -21,6 +21,8 @@ import java.util.Map;
 import java.util.Optional;
 import javax.xml.xpath.XPathExpressionException;
 
+import org.hamcrest.Matcher;
+
 import org.springframework.http.HttpHeaders;
 import org.springframework.lang.Nullable;
 import org.springframework.test.util.XpathExpectationsHelper;
@@ -62,47 +64,68 @@ public class XpathAssertions {
 
 
 	/**
-	 * Delegates to {@link XpathExpectationsHelper#assertString(byte[], String, String)}
+	 * Delegates to {@link XpathExpectationsHelper#assertString(byte[], String, String)}.
 	 */
 	public WebTestClient.BodyContentSpec isEqualTo(String expectedValue) {
 		return assertWith(() -> this.xpathHelper.assertString(getContent(), getCharset(), expectedValue));
 	}
 
 	/**
-	 * Delegates to {@link XpathExpectationsHelper#assertNumber(byte[], String, Double)}
+	 * Delegates to {@link XpathExpectationsHelper#assertNumber(byte[], String, Double)}.
 	 */
 	public WebTestClient.BodyContentSpec isEqualTo(Double expectedValue) {
 		return assertWith(() -> this.xpathHelper.assertNumber(getContent(), getCharset(), expectedValue));
 	}
 
 	/**
-	 * Delegates to {@link XpathExpectationsHelper#assertBoolean(byte[], String, boolean)}
+	 * Delegates to {@link XpathExpectationsHelper#assertBoolean(byte[], String, boolean)}.
 	 */
 	public WebTestClient.BodyContentSpec isEqualTo(boolean expectedValue) {
 		return assertWith(() -> this.xpathHelper.assertBoolean(getContent(), getCharset(), expectedValue));
 	}
 
 	/**
-	 * Delegates to {@link XpathExpectationsHelper#exists(byte[], String)}
+	 * Delegates to {@link XpathExpectationsHelper#exists(byte[], String)}.
 	 */
 	public WebTestClient.BodyContentSpec exists() {
 		return assertWith(() -> this.xpathHelper.exists(getContent(), getCharset()));
 	}
 
 	/**
-	 * Delegates to {@link XpathExpectationsHelper#doesNotExist(byte[], String)}
+	 * Delegates to {@link XpathExpectationsHelper#doesNotExist(byte[], String)}.
 	 */
 	public WebTestClient.BodyContentSpec doesNotExist() {
 		return assertWith(() -> this.xpathHelper.doesNotExist(getContent(), getCharset()));
 	}
 
 	/**
-	 * Delegates to {@link XpathExpectationsHelper[#assertNodeCount(byte[], String, int)}
+	 * Delegates to {@link XpathExpectationsHelper#assertNodeCount(byte[], String, int)}.
 	 */
 	public WebTestClient.BodyContentSpec nodeCount(int expectedCount) {
 		return assertWith(() -> this.xpathHelper.assertNodeCount(getContent(), getCharset(), expectedCount));
 	}
 
+	/**
+	 * Delegates to {@link XpathExpectationsHelper#assertString(byte[], String, Matcher)}.
+	 */
+	public WebTestClient.BodyContentSpec string(Matcher<? super String> matcher){
+		return assertWith(() -> this.xpathHelper.assertString(getContent(), getCharset(), matcher));
+	}
+
+	/**
+	 * Delegates to {@link XpathExpectationsHelper#assertNumber(byte[], String, Matcher)}.
+	 */
+	public WebTestClient.BodyContentSpec number(Matcher<? super Double> matcher){
+		return assertWith(() -> this.xpathHelper.assertNumber(getContent(), getCharset(), matcher));
+	}
+
+	/**
+	 * Delegates to {@link XpathExpectationsHelper#assertNodeCount(byte[], String, Matcher)}.
+	 */
+	public WebTestClient.BodyContentSpec nodeCount(Matcher<Integer> matcher){
+		return assertWith(() -> this.xpathHelper.assertNodeCount(getContent(), getCharset(), matcher));
+	}
+
 
 	private WebTestClient.BodyContentSpec assertWith(CheckedExceptionTask task) {
 		try {

spring-test/src/test/java/org/springframework/test/web/reactive/server/HeaderAssertionTests.java

@@ -30,6 +30,7 @@ import org.springframework.http.MediaType;
 import org.springframework.mock.http.client.reactive.MockClientHttpRequest;
 import org.springframework.mock.http.client.reactive.MockClientHttpResponse;
 
+import static org.hamcrest.CoreMatchers.*;
 import static org.junit.Assert.*;
 import static org.mockito.Mockito.*;
 
@@ -125,6 +126,15 @@ public class HeaderAssertionTests {
 		}
 	}
 
+	@Test
+	public void valueMatcher() {
+		HttpHeaders headers = new HttpHeaders();
+		headers.add("foo", "bar");
+		HeaderAssertions assertions = headerAssertions(headers);
+
+		assertions.value("foo", containsString("a"));
+	}
+
 	@Test
 	public void exists() {
 		HttpHeaders headers = new HttpHeaders();

spring-test/src/test/java/org/springframework/test/web/reactive/server/StatusAssertionTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 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.
@@ -26,6 +26,7 @@ import org.springframework.http.HttpStatus;
 import org.springframework.mock.http.client.reactive.MockClientHttpRequest;
 import org.springframework.mock.http.client.reactive.MockClientHttpResponse;
 
+import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 import static org.mockito.Mockito.*;
 
@@ -158,6 +159,23 @@ public class StatusAssertionTests {
 		}
 	}
 
+	@Test
+	public void matches() {
+		StatusAssertions assertions = statusAssertions(HttpStatus.CONFLICT);
+
+		// Success
+		assertions.value(equalTo(409));
+		assertions.value(greaterThan(400));
+
+		try {
+			assertions.value(equalTo(200));
+			fail("Wrong status expected");
+		}
+		catch (AssertionError error) {
+			// Expected
+		}
+	}
+
 
 	private StatusAssertions statusAssertions(HttpStatus status) {
 		MockClientHttpRequest request = new MockClientHttpRequest(HttpMethod.GET, URI.create("/"));

spring-test/src/test/java/org/springframework/test/web/reactive/server/samples/JsonContentTests.java

@@ -31,6 +31,8 @@ import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
+import static org.hamcrest.Matchers.*;
+
 /**
  * Samples of tests using {@link WebTestClient} with serialized JSON content.
  *
@@ -64,16 +66,14 @@ public class JsonContentTests {
 				.jsonPath("$[2].name").isEqualTo("John");
 	}
 
-	@Test // https://stackoverflow.com/questions/49149376/webtestclient-check-that-jsonpath-contains-sub-string
+	@Test
-	public void jsonPathContainsSubstringViaRegex() {
+	public void jsonPathMatches() {
 		this.client.get().uri("/persons/John")
 				.accept(MediaType.APPLICATION_JSON_UTF8)
 				.exchange()
 				.expectStatus().isOk()
 				.expectBody()
-				// The following determines if at least one person is returned with a
+				.jsonPath("$.name").value(containsString("oh"));
-				// name containing "oh", and "John" matches that.
-				.jsonPath("$[?(@.name =~ /.*oh.*/)].name").hasJsonPath();
 	}
 
 	@Test

spring-test/src/test/java/org/springframework/test/web/reactive/server/samples/ResponseEntityTests.java

@@ -38,11 +38,10 @@ import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
-import static java.time.Duration.ofMillis;
+import static java.time.Duration.*;
-import static org.hamcrest.CoreMatchers.endsWith;
+import static org.hamcrest.CoreMatchers.*;
-import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.*;
-import static org.junit.Assert.assertThat;
+import static org.springframework.http.MediaType.*;
-import static org.springframework.http.MediaType.TEXT_EVENT_STREAM;
 
 /**
  * Annotated controllers accepting and returning typed Objects.
@@ -67,6 +66,15 @@ public class ResponseEntityTests {
 				.expectBody(Person.class).isEqualTo(new Person("John"));
 	}
 
+	@Test
+	public void entityMatcher() {
+		this.client.get().uri("/John")
+				.exchange()
+				.expectStatus().isOk()
+				.expectHeader().contentType(MediaType.APPLICATION_JSON_UTF8)
+				.expectBody(Person.class).value(Person::getName, startsWith("Joh"));
+	}
+
 	@Test
 	public void entityWithConsumer() {
 		this.client.get().uri("/John")

spring-test/src/test/java/org/springframework/test/web/reactive/server/samples/XmlContentTests.java

@@ -38,6 +38,8 @@ import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
+import static org.hamcrest.Matchers.*;
+
 /**
  * Samples of tests using {@link WebTestClient} with XML content.
  *
@@ -83,6 +85,16 @@ public class XmlContentTests {
 				.xpath("/persons/person[3]/name").isEqualTo("John");
 	}
 
+	@Test
+	public void xpathMatches() {
+		this.client.get().uri("/persons")
+				.accept(MediaType.APPLICATION_XML)
+				.exchange()
+				.expectStatus().isOk()
+				.expectBody()
+				.xpath("//person/name").string(startsWith("J"));
+	}
+
 	@Test
 	public void xpathContainsSubstringViaRegex() {
 		this.client.get().uri("/persons/John")