 
     test.equal intercepted.length, 1, intercepted
 
+    test.isTrue _.isString(intercepted[0]), intercepted[0]
     intercepted = EJSON.parse intercepted[0]
 
     test.equal intercepted.message, "Document's '#{ postId }' field 'author' is referencing a nonexistent document 'nonexistent'"


    test.equal intercepted.length, 1, intercepted

    intercepted = EJSON.parse intercepted[0]

    test.equal intercepted.message, "Document's '#{ postId }' field 'subscribers' was updated with a non-array value: 'foobar'"


    test.equal intercepted.length, 1, intercepted

    test.isTrue _.isString(intercepted[0]), intercepted[0]
    intercepted = EJSON.parse intercepted[0]

    test.equal intercepted.message, "Document's '#{ postId }' field 'author' was updated with an invalid value: null"
