In the Microsoft DataTypes test set, test

<test group="anyURI_a004_1339" name="anyURI_a004_1339"/>

the schema contains:

	<!-- should give only 3 warning for the unresolved schemaLocations -->
	<xsd:include schemaLocation="ftp://ftp.is.co.za/rfc/rfc1808.txt"/>
	<xsd:import schemaLocation="gopher://spinaltap.micro.umn.edu/00/Weather/California/Los%20Angeles" namespace="gopher://spinaltap.micro.umn.edu/00/Weather/California/Los%20Angeles"/>
	<xsd:redefine schemaLocation="mailto:mduerst@ifi.unizh.ch"/>

The test appears to be written on the assumption that the URIs should fail to resolve, and that this is a warning condition rather than an error. However, the first URI does resolve, and yields a resource that cannot be parsed as XML.

XML Schema Part 1, Schema Representation Constraint: Inclusion Constraints and Semantics states:

In addition to the conditions imposed on <include> element information items by the schema for schemas, all of the following must be true:
1 If the ·actual value· of the schemaLocation [attribute] successfully resolves one of the following must be true:
1.1 It resolves to (a fragment of) a resource which is an XML document (of type application/xml or text/xml with an XML declaration for preference, but this is not required), which in turn corresponds to a <schema> element information item in a well-formed information set, which in turn corresponds to a valid schema.
1.2 It resolves to a <schema> element information item in a well-formed information set, which in turn corresponds to a valid schema.

Given that the actual value resolves, and neither 1.1 nor 1.2 is true, the schema is invalid.