implement blank resumption tokens for ActiveRecord providers

- replace blank? for non-ActiveRecord contexts
- add blank resumption tokens to final partial lists for ActiveRecord providers
- test ActiveRecord and test providers for blank final resumption tokens

Author: barmintor

lib/oai/provider/model/activerecord_caching_wrapper.rb

@@ -83,7 +83,7 @@ def next_set(token_string)
       if token.last * @limit + @limit < total
         select_partial(token)
       else
-        select_partial(token).records
+        select_partial(token).tap { |list| list.instance_variable_set(:@token, list.token.next(nil)) }
       end
     end
 

lib/oai/provider/model/activerecord_wrapper.rb

@@ -134,9 +134,7 @@ def next_set(find_scope, token_string)
       if @limit < total
         select_partial(find_scope, token)
       else # end of result set
-        find_scope.where(token_conditions(token))
-          .limit(@limit)
-          .order("#{identifier_field} asc")
+        select_partial(find_scope, token).tap { |list| list.instance_variable_set(:@token, list.token.next(nil)) }
       end
     end
 

lib/oai/provider/resumption_token.rb

@@ -122,7 +122,7 @@ def last=(value)
     end
 
     def encode_conditions
-      return "" if last_str.blank?
+      return "" if last_str.nil? || last_str.to_s.strip.eql?("")
 
       encoded_token = @prefix.to_s.dup
       encoded_token << ".s(#{set})" if set

test/activerecord_provider/tc_caching_paging_provider.rb

@@ -17,8 +17,9 @@ def test_full_harvest
     token = doc.elements["/OAI-PMH/ListRecords/resumptionToken"].text
     assert_equal 26, doc.elements["/OAI-PMH/ListRecords"].size
     doc = Document.new(@provider.list_records(:resumption_token => token))
-    assert_nil doc.elements["/OAI-PMH/ListRecords/resumptionToken"]
-    assert_equal 25, doc.elements["/OAI-PMH/ListRecords"].size
+    assert_not_nil doc.elements["/OAI-PMH/ListRecords/resumptionToken"]
+    assert_nil doc.elements["/OAI-PMH/ListRecords/resumptionToken"].text
+    assert_equal 26, doc.elements["/OAI-PMH/ListRecords"].to_a.size
   end
 
   def test_from_and_until
@@ -37,8 +38,9 @@ def test_from_and_until
     token = doc.elements["/OAI-PMH/ListRecords/resumptionToken"].text
     assert_not_nil doc.elements["/OAI-PMH/ListRecords/resumptionToken"]
     doc = Document.new(@provider.list_records(:resumption_token => token))
-    assert_equal 25, doc.elements["/OAI-PMH/ListRecords"].size
-    assert_nil doc.elements["/OAI-PMH/ListRecords/resumptionToken"]
+    assert_not_nil doc.elements["/OAI-PMH/ListRecords/resumptionToken"]
+    assert_nil doc.elements["/OAI-PMH/ListRecords/resumptionToken"].text
+    assert_equal 26, doc.elements["/OAI-PMH/ListRecords"].to_a.size
   end
 
   def setup

test/activerecord_provider/tc_simple_paging_provider.rb

@@ -20,8 +20,9 @@ def test_full_harvest
     assert_equal 26, doc.elements["/OAI-PMH/ListRecords"].to_a.size
 
     doc = Document.new(@provider.list_records(:resumption_token => token))
-    assert_nil doc.elements["/OAI-PMH/ListRecords/resumptionToken"]
-    assert_equal 25, doc.elements["/OAI-PMH/ListRecords"].to_a.size
+    assert_not_nil doc.elements["/OAI-PMH/ListRecords/resumptionToken"]
+    assert_nil doc.elements["/OAI-PMH/ListRecords/resumptionToken"].text
+    assert_equal 26, doc.elements["/OAI-PMH/ListRecords"].to_a.size
   end
 
   def test_non_integer_identifiers_resumption
@@ -58,8 +59,9 @@ def test_from_and_until
     assert_not_nil doc.elements["/OAI-PMH/ListRecords/resumptionToken"]
     token = doc.elements["/OAI-PMH/ListRecords/resumptionToken"].text
     doc = Document.new(@provider.list_records(:resumption_token => token))
-    assert_equal 25, doc.elements["/OAI-PMH/ListRecords"].to_a.size
-    assert_nil doc.elements["/OAI-PMH/ListRecords/resumptionToken"]
+    assert_not_nil doc.elements["/OAI-PMH/ListRecords/resumptionToken"]
+    assert_nil doc.elements["/OAI-PMH/ListRecords/resumptionToken"].text
+    assert_equal 26, doc.elements["/OAI-PMH/ListRecords"].to_a.size
   end
 
   def setup

test/provider/models.rb

@@ -68,7 +68,7 @@ def find(selector, opts={})
           if token.last < @groups.size - 1
             PartialResult.new(@groups[token.last], token.next(token.last + 1))
           else
-            @groups[token.last]
+            PartialResult.new(@groups[token.last], token.next(nil))
           end
         rescue
           raise OAI::ResumptionTokenException.new

test/provider/tc_functional_tokens.rb

@@ -46,9 +46,10 @@ def test_from_and_until_with_resumption_tokens
     token = doc.elements["/OAI-PMH/ListRecords/resumptionToken"].text
 
     doc = Document.new(@provider.list_records(:resumption_token => token))
-    assert_nil doc.elements["/OAI-PMH/ListRecords/resumptionToken"]
-    assert_equal (300 % @provider.model.limit), doc.elements["/OAI-PMH/ListRecords"].to_a.size
-    token = doc.elements["/OAI-PMH/ListRecords/resumptionToken"].text
+    # assert that ListRecords includes remaining records and an empty resumption token
+    assert_equal (301 % @provider.model.limit), doc.elements["/OAI-PMH/ListRecords"].to_a.size
+    assert_not_nil doc.elements["/OAI-PMH/ListRecords/resumptionToken"]
+    assert_nil doc.elements["/OAI-PMH/ListRecords/resumptionToken"].text
   end
 
 end