diff --git a/tests/search/sorting/docs-rankfeatures.json b/tests/search/sorting/docs-rankfeatures.json
new file mode 100644
index 000000000..07218170d
--- /dev/null
+++ b/tests/search/sorting/docs-rankfeatures.json
@@ -0,0 +1,7 @@
+[
+  {"id":"id:test:rankfeatures::0","fields":{"title":"alpha zero","year":2001,"price":10.0,"category":"red"}},
+  {"id":"id:test:rankfeatures::1","fields":{"title":"alpha alpha one","year":2002,"price":30.0,"category":"blue"}},
+  {"id":"id:test:rankfeatures::2","fields":{"title":"alpha alpha alpha two","year":2013,"price":20.0,"category":"red"}},
+  {"id":"id:test:rankfeatures::3","fields":{"title":"alpha alpha alpha alpha three","year":2014,"price":50.0,"category":"blue"}},
+  {"id":"id:test:rankfeatures::4","fields":{"title":"alpha alpha alpha alpha alpha four","year":2025,"price":40.0,"category":"red"}}
+]
diff --git a/tests/search/sorting/rankfeatures.sd b/tests/search/sorting/rankfeatures.sd
new file mode 100644
index 000000000..4a7d01d11
--- /dev/null
+++ b/tests/search/sorting/rankfeatures.sd
@@ -0,0 +1,76 @@
+# Copyright Vespa.ai. All rights reserved.
+schema rankfeatures {
+
+  document rankfeatures {
+
+    # query field, repeated "alpha" gives each document a distinct bm25 score
+    field title type string {
+      indexing: summary | index
+      index: enable-bm25
+    }
+
+    field year type int {
+      indexing: summary | attribute
+    }
+
+    field price type double {
+      indexing: summary | attribute
+    }
+
+    field category type string {
+      indexing: summary | attribute
+    }
+  }
+
+  fieldset default {
+    fields: title
+  }
+
+  rank-profile default {
+    first-phase {
+      expression: attribute(year)
+    }
+  }
+
+  # The rank features listed in sort-features may be used as sorting keys
+  # from a query, as sortspec=feature(<name>)
+  rank-profile sorting inherits default {
+    function inv_price() {
+      expression: 1000.0 - attribute(price)
+    }
+    function decade() {
+      expression: floor(attribute(year) / 10)
+    }
+    function title_bm25() {
+      expression: bm25(title)
+    }
+    sort-features {
+      inv_price
+      decade
+      title_bm25
+      nativeRank
+    }
+  }
+
+  # sort-features are inherited
+  rank-profile sorting_child inherits sorting {
+  }
+
+  # ... but an empty block clears what was inherited
+  rank-profile sorting_cleared inherits sorting {
+    sort-features {}
+  }
+
+  rank-profile with_second_phase inherits sorting {
+    second-phase {
+      expression: firstPhase * 100
+    }
+  }
+
+  # same functions, but none of them declared sortable
+  rank-profile no_sort_features inherits default {
+    function inv_price() {
+      expression: 1000.0 - attribute(price)
+    }
+  }
+}
diff --git a/tests/search/sorting/sorting_rankfeatures.rb b/tests/search/sorting/sorting_rankfeatures.rb
new file mode 100644
index 000000000..e1e277055
--- /dev/null
+++ b/tests/search/sorting/sorting_rankfeatures.rb
@@ -0,0 +1,203 @@
+# Copyright Vespa.ai. All rights reserved.
+
+require 'search_test'
+
+class SortingRankFeatures < SearchTest
+
+  # Description: Sorting on rank features declared in a rank profile's sort-features block
+  # Component: Search
+  # Feature: Query functionality
+
+  QUERY = 'select * from sources * where title contains "alpha"'
+
+  def setup
+    set_owner('arnej')
+    set_description('Test sorting on rank features listed in sort-features')
+  end
+
+  # Documents (see docs-rankfeatures.json), all matching "alpha":
+  #
+  #  id | title occurrences | year | price | category | inv_price | decade
+  #  ---+-------------------+------+-------+----------+-----------+-------
+  #   0 | 1                 | 2001 |  10.0 | red      |     990.0 |    200
+  #   1 | 2                 | 2002 |  30.0 | blue     |     970.0 |    200
+  #   2 | 3                 | 2013 |  20.0 | red      |     980.0 |    201
+  #   3 | 4                 | 2014 |  50.0 | blue     |     950.0 |    201
+  #   4 | 5                 | 2025 |  40.0 | red      |     960.0 |    202
+  #
+  # bm25(title) grows with the number of occurrences, so it orders 0 < 1 < 2 < 3 < 4.
+  # The first-phase score is attribute(year), which orders 0 < 1 < 2 < 3 < 4 as well.
+
+  def test_sort_by_rank_feature
+    deploy_app(SearchApp.new.sd(selfdir + 'rankfeatures.sd'))
+    start
+    feed_and_wait_for_docs('rankfeatures', 5, :file => selfdir + 'docs-rankfeatures.json')
+
+    check_single_level_sorting
+    check_multi_level_sorting
+    check_ranking_is_not_activated
+    check_offset_and_hits
+    check_yql_ordering
+    check_inheritance
+    check_errors
+  end
+
+  # A rank feature can only be used for sorting when the schema is indexed
+  def test_sort_by_rank_feature_streaming
+    deploy_app(SearchApp.new.sd(selfdir + 'rankfeatures.sd').streaming)
+    start
+
+    # The query is rejected in the container, so no documents are needed
+    check_error({ 'ranking' => 'sorting', 'sortspec' => '-feature(inv_price)',
+                  'streaming.selection' => 'true' },
+                /cannot sort by feature\(inv_price\).*is not indexed/)
+  end
+
+  def check_single_level_sorting
+    # ascending inv_price is descending price
+    check_order({ 'ranking' => 'sorting', 'sortspec' => '+feature(inv_price)' }, [3, 4, 1, 2, 0])
+    check_order({ 'ranking' => 'sorting', 'sortspec' => '-feature(inv_price)' }, [0, 2, 1, 4, 3])
+    # unlike attribute sorting, feature sorting defaults to ascending
+    check_order({ 'ranking' => 'sorting', 'sortspec' => 'feature(inv_price)' }, [3, 4, 1, 2, 0])
+
+    # a feature using the query, not just attributes
+    check_order({ 'ranking' => 'sorting', 'sortspec' => '+feature(title_bm25)' }, [0, 1, 2, 3, 4])
+    check_order({ 'ranking' => 'sorting', 'sortspec' => '-feature(title_bm25)' }, [4, 3, 2, 1, 0])
+
+    # a built-in feature (not a function, so not renamed on the way to the backend).
+    # The scores depend on the nativeRank tuning, so instead of a fixed order we
+    # check that it gives a total order, descending being the reverse of ascending.
+    ascending = feature_sorted_ids({ 'ranking' => 'sorting', 'sortspec' => '+feature(nativeRank)' })
+    descending = feature_sorted_ids({ 'ranking' => 'sorting', 'sortspec' => '-feature(nativeRank)' })
+    assert_equal([0, 1, 2, 3, 4], ascending.sort)
+    assert_equal(ascending.reverse, descending)
+  end
+
+  def check_multi_level_sorting
+    # decade is a tie for {0,1} and {2,3}, broken by the second sort level
+    check_order({ 'ranking' => 'sorting', 'sortspec' => '+feature(decade) -[rank]' }, [1, 0, 3, 2, 4])
+    check_order({ 'ranking' => 'sorting', 'sortspec' => '+feature(decade) +[rank]' }, [0, 1, 2, 3, 4])
+    # feature followed by attribute
+    check_order({ 'ranking' => 'sorting', 'sortspec' => '+feature(decade) +price' }, [0, 1, 2, 3, 4])
+    check_order({ 'ranking' => 'sorting', 'sortspec' => '-feature(decade) -price' }, [4, 3, 2, 1, 0])
+    # feature followed by feature
+    check_order({ 'ranking' => 'sorting', 'sortspec' => '+feature(decade) -feature(inv_price)' }, [0, 1, 2, 3, 4])
+    # attribute followed by feature
+    check_order({ 'ranking' => 'sorting', 'sortspec' => '+category -feature(inv_price)' }, [1, 3, 0, 2, 4])
+    # the same feature used twice
+    check_order({ 'ranking' => 'sorting', 'sortspec' => '-feature(inv_price) +feature(inv_price)' }, [0, 2, 1, 4, 3])
+  end
+
+  # Sorting on a rank feature alone does not activate ranking, so all hits get relevance 0.
+  # Adding [rank] to the sort spec brings ranking back.
+  def check_ranking_is_not_activated
+    result = check_order({ 'ranking' => 'sorting', 'sortspec' => '-feature(inv_price)' }, [0, 2, 1, 4, 3])
+    assert_relevancies(result, [0.0, 0.0, 0.0, 0.0, 0.0])
+
+    result = check_order({ 'ranking' => 'sorting', 'sortspec' => '-feature(inv_price) -[rank]' }, [0, 2, 1, 4, 3])
+    assert_relevancies(result, [2001.0, 2013.0, 2002.0, 2025.0, 2014.0])
+
+    # second-phase ranking is not run either
+    result = check_order({ 'ranking' => 'with_second_phase', 'sortspec' => '-feature(inv_price)' }, [0, 2, 1, 4, 3])
+    assert_relevancies(result, [0.0, 0.0, 0.0, 0.0, 0.0])
+
+    result = check_order({ 'ranking' => 'with_second_phase', 'sortspec' => '-feature(inv_price) -[rank]' }, [0, 2, 1, 4, 3])
+    assert_relevancies(result, [200100.0, 201300.0, 200200.0, 202500.0, 201400.0])
+  end
+
+  def check_offset_and_hits
+    result = do_search({ 'ranking' => 'sorting', 'sortspec' => '+feature(inv_price)',
+                         'hits' => '2', 'offset' => '1' })
+    assert_no_errors(result)
+    assert_hitcount(result, 5)
+    assert_equal([4, 1], ids_of(result))
+  end
+
+  def check_yql_ordering
+    yql = QUERY + ' order by [{"function": "feature"}]inv_price desc'
+    result = do_search({ 'yql' => yql, 'ranking' => 'sorting' })
+    assert_no_errors(result)
+    assert_hitcount(result, 5)
+    assert_equal([0, 2, 1, 4, 3], ids_of(result))
+
+    yql = QUERY + ' order by [{"function": "feature"}]inv_price asc'
+    result = do_search({ 'yql' => yql, 'ranking' => 'sorting' })
+    assert_no_errors(result)
+    assert_equal([3, 4, 1, 2, 0], ids_of(result))
+  end
+
+  def check_inheritance
+    check_order({ 'ranking' => 'sorting_child', 'sortspec' => '-feature(inv_price)' }, [0, 2, 1, 4, 3])
+    check_order({ 'ranking' => 'with_second_phase', 'sortspec' => '+feature(decade) +price' }, [0, 1, 2, 3, 4])
+  end
+
+  def check_errors
+    # not listed in sort-features
+    check_error({ 'ranking' => 'sorting', 'sortspec' => '-feature(no_such_feature)' },
+                /cannot sort by feature\(no_such_feature\).*does not allow it/)
+    # the function exists, but the rank profile has no sort-features at all
+    check_error({ 'ranking' => 'no_sort_features', 'sortspec' => '-feature(inv_price)' },
+                /cannot sort by feature\(inv_price\).*does not allow it/)
+    # inherited sort-features cleared by an empty block
+    check_error({ 'ranking' => 'sorting_cleared', 'sortspec' => '-feature(inv_price)' },
+                /cannot sort by feature\(inv_price\).*does not allow it/)
+    # the default rank profile does not allow it either
+    check_error({ 'sortspec' => '-feature(inv_price)' },
+                /cannot sort by feature\(inv_price\).*does not allow it/)
+    # only bare schema identifiers are legal feature names
+    check_error({ 'ranking' => 'sorting', 'sortspec' => '-feature(inv.price)' },
+                /Illegal feature name 'inv\.price' for sorting/)
+    # missing() does not apply to features, they always have a value
+    check_error({ 'ranking' => 'sorting', 'sortspec' => '-missing(feature(inv_price),first)' },
+                /Cannot use missing\(\) with feature\(\.\.\.\) sorting/)
+  end
+
+  def do_search(params)
+    form = { 'yql' => QUERY, 'hits' => '10' }.merge(params)
+    encoded_form = URI.encode_www_form(form.to_a)
+    puts "Query: #{encoded_form}"
+    search(encoded_form)
+  end
+
+  def ids_of(result)
+    (0...result.hit.size).map do |i|
+      result.hit[i].field['documentid'].sub(/id:test:rankfeatures::/, '').to_i
+    end
+  end
+
+  def assert_no_errors(result)
+    assert_nil(result.errorlist, "Unexpected error(s): #{result.errorlist}")
+  end
+
+  def check_order(params, exp_ids)
+    result = do_search(params)
+    assert_no_errors(result)
+    assert_hitcount(result, 5)
+    assert_equal(exp_ids, ids_of(result))
+    result
+  end
+
+  # Returns the hit ids of a query sorting on a rank feature only, where all
+  # hits are expected to be unranked
+  def feature_sorted_ids(params)
+    result = do_search(params)
+    assert_no_errors(result)
+    assert_hitcount(result, 5)
+    assert_relevancies(result, [0.0] * 5)
+    ids_of(result)
+  end
+
+  def assert_relevancies(result, exp_relevancies)
+    act_relevancies = (0...result.hit.size).map { |i| result.hit[i].field['relevancy'].to_f }
+    assert_equal(exp_relevancies, act_relevancies)
+  end
+
+  def check_error(params, exp_message)
+    result = do_search(params)
+    assert_not_nil(result.errorlist, "Expected an error, got #{result}")
+    message = result.errorlist[0]['message']
+    puts "Error is #{message}"
+    assert_match(exp_message, message)
+  end
+
+end