Upgrade to HTMLUnit 2.23 (+selenium module 2.23.2)

Fixes gh-7232

spring-boot-dependencies/pom.xml

@@ -89,7 +89,7 @@
 		<hikaricp.version>2.4.7</hikaricp.version>
 		<hikaricp-java6.version>2.3.13</hikaricp-java6.version>
 		<hsqldb.version>2.3.3</hsqldb.version>
-		<htmlunit.version>2.21</htmlunit.version>
+		<htmlunit.version>2.23</htmlunit.version>
 		<httpasyncclient.version>4.1.2</httpasyncclient.version>
 		<httpclient.version>4.5.2</httpclient.version>
 		<httpcore.version>4.4.5</httpcore.version>
@@ -139,6 +139,7 @@
 		<reactor.version>2.0.8.RELEASE</reactor.version>
 		<reactor-spring.version>2.0.7.RELEASE</reactor-spring.version>
 		<selenium.version>2.53.1</selenium.version>
+		<selenium-htmlunit.version>2.23.2</selenium-htmlunit.version>
 		<sendgrid.version>2.2.2</sendgrid.version>
 		<servlet-api.version>3.1.0</servlet-api.version>
 		<simple-json.version>1.1.1</simple-json.version>
@@ -1923,7 +1924,7 @@
 			<dependency>
 				<groupId>org.seleniumhq.selenium</groupId>
 				<artifactId>htmlunit-driver</artifactId>
-				<version>${htmlunit.version}</version>
+				<version>${selenium-htmlunit.version}</version>
 			</dependency>
 			<dependency>
 				<groupId>org.seleniumhq.selenium</groupId>

spring-boot-test/src/test/java/org/springframework/boot/test/web/htmlunit/webdriver/LocalHostWebConnectionHtmlUnitDriverTests.java

@@ -81,7 +81,9 @@ public class LocalHostWebConnectionHtmlUnitDriverTests {
 			throws Exception {
 		this.thrown.expect(IllegalArgumentException.class);
 		this.thrown.expectMessage("Environment must not be null");
-		new LocalHostWebConnectionHtmlUnitDriver(null, mock(Capabilities.class));
+		Capabilities capabilities = mock(Capabilities.class);
+		given(capabilities.getBrowserName()).willReturn("chrome");
+		new LocalHostWebConnectionHtmlUnitDriver(null, capabilities);
 	}
 
 	@Test