Strip supplied value, type, and subtype in MediaType

In order to support scenarios where the user inadvertently supplied a
value, type, or subtype with leading or trailing whitespace, this
commit consistently strips a supplied value, type, or subtype in
MediaType like we do elsewhere in the code base.

Closes #4893

Author: sbrannen

documentation/src/docs/asciidoc/release-notes/release-notes-6.0.0-RC3.adoc

@@ -48,7 +48,8 @@ JUnit repository on GitHub.
 [[release-notes-6.0.0-RC3-junit-jupiter-new-features-and-improvements]]
 ==== New Features and Improvements
 
-* ❓
+* `MediaType` now strips leading and trailing whitespace from a supplied `value`, `type`,
+  or `subtype`.
 
 
 [[release-notes-6.0.0-RC3-junit-vintage]]

junit-jupiter-api/src/main/java/org/junit/jupiter/api/extension/MediaType.java

@@ -112,7 +112,7 @@ public static MediaType parse(String value) {
 	public static MediaType create(String type, String subtype) {
 		Preconditions.notNull(type, "type must not be null");
 		Preconditions.notNull(subtype, "subtype must not be null");
-		return new MediaType(type + "/" + subtype);
+		return new MediaType(type.strip() + "/" + subtype.strip());
 	}
 
 	/**
@@ -127,13 +127,14 @@ public static MediaType create(String type, String subtype, Charset charset) {
 		Preconditions.notNull(type, "type must not be null");
 		Preconditions.notNull(subtype, "subtype must not be null");
 		Preconditions.notNull(charset, "charset must not be null");
-		return new MediaType(type + "/" + subtype + "; charset=" + charset.name());
+		return new MediaType(type.strip() + "/" + subtype.strip() + "; charset=" + charset.name());
 	}
 
 	private MediaType(String value) {
-		Matcher matcher = PATTERN.matcher(Preconditions.notNull(value, "value must not be null"));
-		Preconditions.condition(matcher.matches(), () -> "Invalid media type: '" + value + "'");
-		this.value = value;
+		String strippedValue = Preconditions.notNull(value, "value must not be null").strip();
+		Matcher matcher = PATTERN.matcher(strippedValue);
+		Preconditions.condition(matcher.matches(), () -> "Invalid media type: '" + strippedValue + "'");
+		this.value = strippedValue;
 	}
 
 	/**

jupiter-tests/src/test/java/org/junit/jupiter/api/extension/MediaTypeTests.java

@@ -45,12 +45,14 @@ void parseWithNullMediaType() {
 		@ValueSource(strings = { "", "   ", "/", " / ", "type", "type/", "/subtype" })
 		void parseWithInvalidMediaType(String mediaType) {
 			assertPreconditionViolationFor(() -> MediaType.parse(mediaType))//
-					.withMessage("Invalid media type: '%s'", mediaType);
+					.withMessage("Invalid media type: '%s'", mediaType.strip());
 		}
 
-		@Test
-		void parse() {
-			assertThat(MediaType.parse("text/plain")).hasToString("text/plain");
+		@ParameterizedTest
+		@ValueSource(strings = { "text/plain", "   text/plain   ", "text/plain; charset=UTF-8",
+				"\t text/plain; charset=UTF-8 \t" })
+		void parse(String value) {
+			assertThat(MediaType.parse(value)).hasToString(value.strip());
 		}
 	}
 
@@ -79,14 +81,14 @@ void createWithNullCharset() {
 		@ValueSource(strings = { "", "   ", "/", " / ", "type/", "/subtype" })
 		void createWithInvalidType(String type) {
 			assertPreconditionViolationFor(() -> MediaType.create(type, "json"))//
-					.withMessage("Invalid media type: '%s/json'", type);
+					.withMessage("Invalid media type: '%s/json'", type.strip());
 		}
 
 		@ParameterizedTest
 		@ValueSource(strings = { "", "   ", "/", " / ", "type/", "/subtype" })
 		void createWithInvalidSubtype(String subtype) {
 			assertPreconditionViolationFor(() -> MediaType.create("application", subtype))//
-					.withMessage("Invalid media type: 'application/%s'", subtype);
+					.withMessage("Invalid media type: 'application/%s'", subtype.strip());
 		}
 
 		@Test