Add ZeroPagesError as a new subclass of ClientError

lib/vbms/errors.rb

@@ -183,6 +183,9 @@ def initialize(cmd, output)
     end
   end
 
+  class ZeroPagesError < ClientError
+  end
+
   class BadClaim < HTTPError; end
   class BadPostalCode < HTTPError; end
   class BadSOAPMessage < HTTPError; end

lib/vbms/service/paged_documents.rb

@@ -12,7 +12,7 @@ def call(file_number:)
         first_page = client.send_request(req)
 
         # interpret a first page with no sections (and no doc count) as equivalent to zero pages.
-        raise ClientError.new("No sections found in first page") if first_page.empty?
+        raise ZeroPagesError.new("No sections found in first page") if first_page.empty?
 
         # response will always be an array. get pagination from the first section.
         (documents << first_page.map { |section| section[:documents] }).flatten!

spec/service/paged_documents_spec.rb

@@ -83,9 +83,9 @@ def next_response
     end
 
     context "when the first page contains no sections" do
-      it "raises a ClientError" do
+      it "raises a ZeroPagesError" do
         allow(client).to receive(:send_request).and_return []
-        expect { subject.call(file_number: file_number) }.to raise_error(VBMS::ClientError)
+        expect { subject.call(file_number: file_number) }.to raise_error(VBMS::ZeroPagesError)
       end
     end
   end