[[mockmvc-server-htmlunit-mah]]
= MockMvc and HtmlUnit

This section describes how to integrate MockMvc and HtmlUnit. Use this option if you want
to use the raw HtmlUnit libraries.

[[mockmvc-server-htmlunit-mah-setup]]
== MockMvc and HtmlUnit Setup

First, make sure that you have included a test dependency on
`org.htmlunit:htmlunit`.

We can easily create an HtmlUnit `WebClient` that integrates with MockMvc by using the
`MockMvcWebClientBuilder`, as follows:

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	WebClient webClient;

	@BeforeEach
	void setup(WebApplicationContext context) {
		webClient = MockMvcWebClientBuilder
				.webAppContextSetup(context)
				.build();
	}
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	lateinit var webClient: WebClient

	@BeforeEach
	fun setup(context: WebApplicationContext) {
		webClient = MockMvcWebClientBuilder
				.webAppContextSetup(context)
				.build()
	}
----
======

NOTE: This is a simple example of using `MockMvcWebClientBuilder`. For advanced usage,
see xref:testing/mockmvc/htmlunit/mah.adoc#spring-mvc-test-server-htmlunit-mah-advanced-builder[Advanced `MockMvcWebClientBuilder`].

This ensures that any URL that references `localhost` as the server is directed to our
`MockMvc` instance without the need for a real HTTP connection. Any other URL is
requested by using a network connection, as normal. This lets us easily test the use of
CDNs.

[[mockmvc-server-htmlunit-mah-usage]]
== MockMvc and HtmlUnit Usage

Now we can use HtmlUnit as we normally would but without the need to deploy our
application to a Servlet container. For example, we can request the view to create a
message with the following:

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	HtmlPage createMsgFormPage = webClient.getPage("http://localhost/messages/form");
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	val createMsgFormPage = webClient.getPage("http://localhost/messages/form")
----
======

NOTE: The default context path is `""`. Alternatively, we can specify the context path,
as described in xref:testing/mockmvc/htmlunit/mah.adoc#spring-mvc-test-server-htmlunit-mah-advanced-builder[Advanced `MockMvcWebClientBuilder`].

Once we have a reference to the `HtmlPage`, we can then fill out the form and submit it
to create a message, as the following example shows:

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	HtmlForm form = createMsgFormPage.getHtmlElementById("messageForm");
	HtmlTextInput summaryInput = createMsgFormPage.getHtmlElementById("summary");
	summaryInput.setValueAttribute("Spring Rocks");
	HtmlTextArea textInput = createMsgFormPage.getHtmlElementById("text");
	textInput.setText("In case you didn't know, Spring Rocks!");
	HtmlSubmitInput submit = form.getOneHtmlElementByAttribute("input", "type", "submit");
	HtmlPage newMessagePage = submit.click();
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	val form = createMsgFormPage.getHtmlElementById("messageForm")
	val summaryInput = createMsgFormPage.getHtmlElementById("summary")
	summaryInput.setValueAttribute("Spring Rocks")
	val textInput = createMsgFormPage.getHtmlElementById("text")
	textInput.setText("In case you didn't know, Spring Rocks!")
	val submit = form.getOneHtmlElementByAttribute("input", "type", "submit")
	val newMessagePage = submit.click()
----
======

Finally, we can verify that a new message was created successfully. The following
assertions use the {assertj-docs}[AssertJ] library:

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	assertThat(newMessagePage.getUrl().toString()).endsWith("/messages/123");
	String id = newMessagePage.getHtmlElementById("id").getTextContent();
	assertThat(id).isEqualTo("123");
	String summary = newMessagePage.getHtmlElementById("summary").getTextContent();
	assertThat(summary).isEqualTo("Spring Rocks");
	String text = newMessagePage.getHtmlElementById("text").getTextContent();
	assertThat(text).isEqualTo("In case you didn't know, Spring Rocks!");
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	assertThat(newMessagePage.getUrl().toString()).endsWith("/messages/123")
	val id = newMessagePage.getHtmlElementById("id").getTextContent()
	assertThat(id).isEqualTo("123")
	val summary = newMessagePage.getHtmlElementById("summary").getTextContent()
	assertThat(summary).isEqualTo("Spring Rocks")
	val text = newMessagePage.getHtmlElementById("text").getTextContent()
	assertThat(text).isEqualTo("In case you didn't know, Spring Rocks!")
----
======

The preceding code improves on our
xref:testing/mockmvc/htmlunit/why.adoc#spring-mvc-test-server-htmlunit-mock-mvc-test[MockMvc test] in a number of ways.
First, we no longer have to explicitly verify our form and then create a request that
looks like the form. Instead, we request the form, fill it out, and submit it, thereby
significantly reducing the overhead.

Another important factor is that https://htmlunit.sourceforge.io/javascript.html[HtmlUnit
uses the Mozilla Rhino engine] to evaluate JavaScript. This means that we can also test
the behavior of JavaScript within our pages.

See the https://htmlunit.sourceforge.io/gettingStarted.html[HtmlUnit documentation] for
additional information about using HtmlUnit.

[[mockmvc-server-htmlunit-mah-advanced-builder]]
== Advanced `MockMvcWebClientBuilder`

In the examples so far, we have used `MockMvcWebClientBuilder` in the simplest way
possible, by building a `WebClient` based on the `WebApplicationContext` loaded for us by
the Spring TestContext Framework. This approach is repeated in the following example:

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	WebClient webClient;

	@BeforeEach
	void setup(WebApplicationContext context) {
		webClient = MockMvcWebClientBuilder
				.webAppContextSetup(context)
				.build();
	}
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	lateinit var webClient: WebClient

	@BeforeEach
	fun setup(context: WebApplicationContext) {
		webClient = MockMvcWebClientBuilder
				.webAppContextSetup(context)
				.build()
	}
----
======

We can also specify additional configuration options, as the following example shows:

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	WebClient webClient;

	@BeforeEach
	void setup() {
		webClient = MockMvcWebClientBuilder
			// demonstrates applying a MockMvcConfigurer (Spring Security)
			.webAppContextSetup(context, springSecurity())
			// for illustration only - defaults to ""
			.contextPath("")
			// By default MockMvc is used for localhost only;
			// the following will use MockMvc for example.com and example.org as well
			.useMockMvcForHosts("example.com","example.org")
			.build();
	}
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	lateinit var webClient: WebClient

	@BeforeEach
	fun setup() {
		webClient = MockMvcWebClientBuilder
			// demonstrates applying a MockMvcConfigurer (Spring Security)
			.webAppContextSetup(context, springSecurity())
			// for illustration only - defaults to ""
			.contextPath("")
			// By default MockMvc is used for localhost only;
			// the following will use MockMvc for example.com and example.org as well
			.useMockMvcForHosts("example.com","example.org")
			.build()
	}
----
======

As an alternative, we can perform the exact same setup by configuring the `MockMvc`
instance separately and supplying it to the `MockMvcWebClientBuilder`, as follows:

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	MockMvc mockMvc = MockMvcBuilders
			.webAppContextSetup(context)
			.apply(springSecurity())
			.build();

	webClient = MockMvcWebClientBuilder
			.mockMvcSetup(mockMvc)
			// for illustration only - defaults to ""
			.contextPath("")
			// By default MockMvc is used for localhost only;
			// the following will use MockMvc for example.com and example.org as well
			.useMockMvcForHosts("example.com","example.org")
			.build();
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	// Not possible in Kotlin until {kotlin-issues}/KT-22208 is fixed
----
======

This is more verbose, but, by building the `WebClient` with a `MockMvc` instance, we have
the full power of MockMvc at our fingertips.

TIP: For additional information on creating a `MockMvc` instance, see
xref:testing/mockmvc/hamcrest/setup.adoc[Configuring MockMvc].

