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 51be1286e5d7..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
@@ -289,7 +289,8 @@ 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
 	 */
@@ -310,14 +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<String> result = new ArrayList<>(mediaTypes.length);
-		result.addAll(Arrays.asList(mediaTypes));
-		this.headers.set("Accept", String.join(", ", result));
+		this.headers.set("Accept", String.join(", ", mediaTypes));
 		return this;
 	}
 
@@ -711,10 +712,15 @@ public final MockHttpServletRequest buildRequest(ServletContext servletContext)
 
 		if (this.content != null && this.content.length > 0) {
 			String requestContentType = request.getContentType();
-			if (requestContentType != null && isValidContentType(requestContentType)) {
-				MediaType mediaType = MediaType.parseMediaType(requestContentType);
-				if (MediaType.APPLICATION_FORM_URLENCODED.includes(mediaType)) {
-					addRequestParams(request, parseFormData(mediaType));
+			if (requestContentType != null) {
+				try {
+					MediaType mediaType = MediaType.parseMediaType(requestContentType);
+					if (MediaType.APPLICATION_FORM_URLENCODED.includes(mediaType)) {
+						addRequestParams(request, parseFormData(mediaType));
+					}
+				}
+				catch (Exception ex) {
+					// Must be invalid, ignore..
 				}
 			}
 		}
@@ -741,26 +747,6 @@ public final MockHttpServletRequest buildRequest(ServletContext servletContext)
 		return request;
 	}
 
-	/**
-	 * Some validation checks to find out if processing of a string value make sense.
-	 */
-	private boolean isValidContentType(String mimeType) {
-		if (!StringUtils.hasLength(mimeType)) {
-			return false;
-		}
-
-		int index = mimeType.indexOf(';');
-		String fullType = (index >= 0 ? mimeType.substring(0, index) : mimeType).trim();
-		if (fullType.isEmpty()) {
-			return false;
-		}
-		int subIndex = fullType.indexOf('/');
-		if (subIndex == -1) {
-			return false;
-		}
-		return subIndex != fullType.length() - 1;
-	}
-
 	/**
 	 * Create a new {@link MockHttpServletRequest} based on the supplied
 	 * {@code ServletContext}.
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 3479d385e622..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
@@ -29,8 +29,6 @@
 import java.util.Locale;
 import java.util.Map;
 
-import java.util.stream.Collectors;
-import java.util.stream.Stream;
 import javax.servlet.ServletContext;
 import javax.servlet.http.Cookie;
 
@@ -339,19 +337,11 @@ public void acceptHeader() {
 		assertThat(result.get(1).toString()).isEqualTo("application/xml");
 	}
 
-	@Test
-	public void anyAcceptMultipleContentTypeViaStringArray() {
+	@Test // gh-2079
+	public void acceptHeaderWithInvalidValues() {
 		this.builder.accept("any", "any2");
-
 		MockHttpServletRequest request = this.builder.buildRequest(this.servletContext);
-		List<String> accept = Collections.list(request.getHeaders("Accept"));
-		List<String> result = Stream.of(accept.get(0).split(","))
-				.map(String::trim)
-				.collect(Collectors.toList());
-
-		assertThat(result.get(0)).isEqualTo("any");
-		assertThat(result).hasSize(2);
-		assertThat(result.get(1)).isEqualTo("any2");
+		assertThat(request.getHeader("Accept")).isEqualTo("any, any2");
 	}
 
 	@Test
@@ -380,17 +370,11 @@ public void contentTypeViaString() {
 		assertThat(contentTypes.get(0)).isEqualTo("text/html");
 	}
 
-	@Test
-	public void anyContentTypeViaString() {
+	@Test // gh-2079
+	public void contentTypeWithInvalidValue() {
 		this.builder.contentType("any");
-
 		MockHttpServletRequest request = this.builder.buildRequest(this.servletContext);
-		String contentType = request.getContentType();
-		List<String> contentTypes = Collections.list(request.getHeaders("Content-Type"));
-
-		assertThat(contentType).isEqualTo("any");
-		assertThat(contentTypes).hasSize(1);
-		assertThat(contentTypes.get(0)).isEqualTo("any");
+		assertThat(request.getContentType()).isEqualTo("any");
 	}
 
 	@Test  // SPR-11308
@@ -402,14 +386,11 @@ public void contentTypeViaHeader() {
 		assertThat(contentType).isEqualTo("text/html");
 	}
 
-	@Test  // SPR-17643
-	public void invalidContentTypeViaHeader() {
+	@Test // gh-2079
+	public void contentTypeViaHeaderWithInvalidValue() {
 		this.builder.header("Content-Type", "yaml");
-		this.builder.content("some content");
 		MockHttpServletRequest request = this.builder.buildRequest(this.servletContext);
-		String contentType = request.getContentType();
-
-		assertThat(contentType).isEqualTo("yaml");
+		assertThat(request.getContentType()).isEqualTo("yaml");
 	}
 
 	@Test  // SPR-11308