There's something wrong with this test, but I can't tell what.

It references the same stylesheet twice.

If it meant to reference import-schema-177a.xsl as a secondary stylesheet, its environment should include schema schema177a.xsd in its environment.  

Neither 177.xsl nor 177a.xsl reference schema002.xsd in the schema location hints.

   <test-case name="import-schema-177">
      <description>
         Test for importing two different schemas with the same @namespace but different import precedence. 
         Cases tested: 
         - elements, attributes or types with the same names but different properties exist in the two schemas 
         - elements, attributes or types with different names exist in the two schemas.
      </description>
      <created by="Michael Kay" on="2012-10-30"/>
      <environment>
         <source role=".">
            <content><![CDATA[<doc/>]]></content>
         </source>
         <schema role="stylesheet-import" file="schema002.xsd" xsd-version="1.0"/>
         <schema role="secondary" file="schema177a.xsd" xsd-version="1.0"/>
      </environment>
      <dependencies>
         <spec value="XSLT20+"/>
         <feature value="schema_aware"/>
      </dependencies>
      <test>
         <stylesheet file="import-schema-177.xsl"/>
         <stylesheet file="import-schema-177.xsl"/>
      </test>
      <result>
         <all-of>
            <assert>/out/type="8006"</assert>
            <assert>/out/elem/text()[1] = "true * true * "</assert>
            <assert xmlns:foo="http://ns.example.com/sch002">/out/elem/foo:complexTest[@foo:type="333"][subject="math"][size="50"]</assert>
            <assert>/out/attrib = "true * 444"</assert>
         </all-of>
      </result>
   </test-case>