diff --git a/spring-test/src/main/java/org/springframework/test/web/servlet/request/MockHttpServletRequestBuilder.java b/spring-test/src/main/java/org/springframework/test/web/servlet/request/MockHttpServletRequestBuilder.java
index c5b527b4adab..ef178c394bb6 100644
--- a/spring-test/src/main/java/org/springframework/test/web/servlet/request/MockHttpServletRequestBuilder.java
+++ b/spring-test/src/main/java/org/springframework/test/web/servlet/request/MockHttpServletRequestBuilder.java
@@ -289,12 +289,14 @@ public MockHttpServletRequestBuilder contentType(MediaType contentType) {
 	}
 
 	/**
-	 * Set the 'Content-Type' header of the request.
+	 * Set the 'Content-Type' header of the request as a raw String value,
+	 * possibly not even well formed (for testing purposes).
 	 * @param contentType the content type
 	 * @since 4.1.2
 	 */
 	public MockHttpServletRequestBuilder contentType(String contentType) {
-		this.contentType = MediaType.parseMediaType(contentType).toString();
+		Assert.notNull(contentType, "'contentType' must not be null");
+		this.contentType = contentType;
 		return this;
 	}
 
@@ -309,16 +311,14 @@ public MockHttpServletRequestBuilder accept(MediaType... mediaTypes) {
 	}
 
 	/**
-	 * Set the 'Accept' header to the given media type(s).
-	 * @param mediaTypes one or more media types
+	 * Set the 'Accept' header using raw String values, possibly not even well
+	 * formed (for testing purposes).
+	 * @param mediaTypes one or more media types; internally joined as
+	 * comma-separated String
 	 */
 	public MockHttpServletRequestBuilder accept(String... mediaTypes) {
 		Assert.notEmpty(mediaTypes, "'mediaTypes' must not be empty");
-		List<MediaType> result = new ArrayList<>(mediaTypes.length);
-		for (String mediaType : mediaTypes) {
-			result.add(MediaType.parseMediaType(mediaType));
-		}
-		this.headers.set("Accept", MediaType.toString(result));
+		this.headers.set("Accept", String.join(", ", mediaTypes));
 		return this;
 	}
 
@@ -713,9 +713,14 @@ public final MockHttpServletRequest buildRequest(ServletContext servletContext)
 		if (this.content != null && this.content.length > 0) {
 			String requestContentType = request.getContentType();
 			if (requestContentType != null) {
-				MediaType mediaType = MediaType.parseMediaType(requestContentType);
-				if (MediaType.APPLICATION_FORM_URLENCODED.includes(mediaType)) {
-					addRequestParams(request, parseFormData(mediaType));
+				try {
+					MediaType mediaType = MediaType.parseMediaType(requestContentType);
+					if (MediaType.APPLICATION_FORM_URLENCODED.includes(mediaType)) {
+						addRequestParams(request, parseFormData(mediaType));
+					}
+				}
+				catch (Exception ex) {
+					// Must be invalid, ignore..
 				}
 			}
 		}
diff --git a/spring-test/src/test/java/org/springframework/test/web/servlet/request/MockHttpServletRequestBuilderTests.java b/spring-test/src/test/java/org/springframework/test/web/servlet/request/MockHttpServletRequestBuilderTests.java
index ae111d7877b6..17fb123acec3 100644
--- a/spring-test/src/test/java/org/springframework/test/web/servlet/request/MockHttpServletRequestBuilderTests.java
+++ b/spring-test/src/test/java/org/springframework/test/web/servlet/request/MockHttpServletRequestBuilderTests.java
@@ -337,6 +337,13 @@ public void acceptHeader() {
 		assertThat(result.get(1).toString()).isEqualTo("application/xml");
 	}
 
+	@Test // gh-2079
+	public void acceptHeaderWithInvalidValues() {
+		this.builder.accept("any", "any2");
+		MockHttpServletRequest request = this.builder.buildRequest(this.servletContext);
+		assertThat(request.getHeader("Accept")).isEqualTo("any, any2");
+	}
+
 	@Test
 	public void contentType() {
 		this.builder.contentType(MediaType.TEXT_HTML);
@@ -363,6 +370,13 @@ public void contentTypeViaString() {
 		assertThat(contentTypes.get(0)).isEqualTo("text/html");
 	}
 
+	@Test // gh-2079
+	public void contentTypeWithInvalidValue() {
+		this.builder.contentType("any");
+		MockHttpServletRequest request = this.builder.buildRequest(this.servletContext);
+		assertThat(request.getContentType()).isEqualTo("any");
+	}
+
 	@Test  // SPR-11308
 	public void contentTypeViaHeader() {
 		this.builder.header("Content-Type", MediaType.TEXT_HTML_VALUE);
@@ -372,6 +386,13 @@ public void contentTypeViaHeader() {
 		assertThat(contentType).isEqualTo("text/html");
 	}
 
+	@Test // gh-2079
+	public void contentTypeViaHeaderWithInvalidValue() {
+		this.builder.header("Content-Type", "yaml");
+		MockHttpServletRequest request = this.builder.buildRequest(this.servletContext);
+		assertThat(request.getContentType()).isEqualTo("yaml");
+	}
+
 	@Test  // SPR-11308
 	public void contentTypeViaMultipleHeaderValues() {
 		this.builder.header("Content-Type", MediaType.TEXT_HTML_VALUE, MediaType.ALL_VALUE);