@Test
public void createTextPlainContentTypeShouldReturnSameInstanceWhenDefaultBuiltInInstanceAlreadyExists() {

	// Given
	String textPlainContentTypeString = "text/plain";
	// When
	ContentType textPlainContentType = ContentType.createContentType(textPlainContentTypeString);
	ContentType otherTextPlainContentType = ContentType.createContentType(textPlainContentTypeString);
	// Then
	assertTrue(textPlainContentType == otherTextPlainContentType);
}