tests: fix pessimizing moves

Remove pessimizing moves, as reported by gcc 9.

tests/data_listeners_test.cc

@@ -96,9 +96,9 @@ results test_data_listeners(cql_test_env& e, sstring cf_name) {
                 results res{li->read, li->write};
                 testlog.info("uninstalled listener {}: rd={} wr={}", li, li->read, li->write);
                 db.data_listeners().uninstall(li);
-                return std::move(res);
+                return res;
             }
-            return std::move(results{});
+            return results{};
         },
         results{},
         [] (results res, results li_res) {

tests/limiting_data_source_test.cc

@@ -86,7 +86,7 @@ data_source prepare_test_skip() {
     BOOST_REQUIRE_EQUAL(1, buf.size());
     BOOST_REQUIRE_EQUAL(0, buf[0]);
     // At this point we have 9 chars buffered in limiting_data_source_impl
-    return std::move(tested);
+    return tested;
 }
 
 }

tests/mutation_source_test.cc

@@ -480,7 +480,7 @@ static void test_streamed_mutation_forwarding_guarantees(populate_fn populate) {
             nullptr,
             streamed_mutation::forwarding::yes));
         res.produces_partition_start(m.decorated_key());
-        return std::move(res);
+        return res;
     };
 
     auto verify_range = [&] (flat_reader_assertions& sm, int start, int end) {

tests/querier_cache.cc

@@ -165,7 +165,7 @@ public:
         , _mutation_source([this] (schema_ptr, const dht::partition_range& range) {
             auto rd = flat_mutation_reader_from_mutations(_mutations, range);
             rd.set_max_buffer_size(max_reader_buffer_size);
-            return std::move(rd);
+            return rd;
         }) {
     }
 

tests/row_cache_test.cc

@@ -2659,7 +2659,7 @@ SEASTAR_TEST_CASE(test_random_row_population) {
             auto rd = cache.make_reader(s.schema(), pr, slice ? *slice : s.schema()->full_slice());
             rd.set_max_buffer_size(1);
             rd.fill_buffer(db::no_timeout).get();
-            return std::move(rd);
+            return rd;
         };
 
         std::vector<query::clustering_range> ranges;
@@ -2774,7 +2774,7 @@ SEASTAR_TEST_CASE(test_continuity_is_populated_when_read_overlaps_with_older_ver
             auto rd = cache.make_reader(s.schema(), pr);
             rd.set_max_buffer_size(1);
             rd.fill_buffer(db::no_timeout).get();
-            return std::move(rd);
+            return rd;
         };
 
         {
@@ -2902,7 +2902,7 @@ SEASTAR_TEST_CASE(test_continuity_population_with_multicolumn_clustering_key) {
             auto rd = cache.make_reader(s, pr, slice ? *slice : s->full_slice());
             rd.set_max_buffer_size(1);
             rd.fill_buffer(db::no_timeout).get();
-            return std::move(rd);
+            return rd;
         };
 
         {
@@ -3009,7 +3009,7 @@ SEASTAR_TEST_CASE(test_concurrent_setting_of_continuity_on_read_upper_bound) {
             auto rd = cache.make_reader(s.schema(), pr, slice ? *slice : s.schema()->full_slice());
             rd.set_max_buffer_size(1);
             rd.fill_buffer(db::no_timeout).get();
-            return std::move(rd);
+            return rd;
         };
 
         {
@@ -3073,7 +3073,7 @@ SEASTAR_TEST_CASE(test_tombstone_merging_of_overlapping_tombstones_in_many_versi
             auto rd = cache.make_reader(s.schema());
             rd.set_max_buffer_size(1);
             rd.fill_buffer(db::no_timeout).get();
-            return std::move(rd);
+            return rd;
         };
 
         apply(cache, underlying, m1);
@@ -3111,7 +3111,7 @@ SEASTAR_TEST_CASE(test_concurrent_reads_and_eviction) {
             auto rd = cache.make_reader(s, pr, slice);
             rd.set_max_buffer_size(3);
             rd.fill_buffer(db::no_timeout).get();
-            return std::move(rd);
+            return rd;
         };
 
         const int n_readers = 3;

tests/sstable_3_x_test.cc

@@ -1346,7 +1346,7 @@ SEASTAR_THREAD_TEST_CASE(test_uncompressed_compound_static_row_read) {
         columns.push_back({s_text_cdef, utf8_type->from_string(text_val)});
         columns.push_back({s_inet_cdef, inet_addr_type->from_string(inet_val)});
 
-        return std::move(columns);
+        return columns;
     };
 
     assert_that(sst.read_rows_flat())
@@ -1689,7 +1689,7 @@ static void test_partition_key_with_values_of_different_types_read(const sstring
         columns.push_back({uuid_cdef, uuid_type->from_string(uuid_val)});
         columns.push_back({text_cdef, utf8_type->from_string(text_val)});
 
-        return std::move(columns);
+        return columns;
     };
 
     assert_that(sst.read_rows_flat())
@@ -1857,7 +1857,7 @@ SEASTAR_THREAD_TEST_CASE(test_uncompressed_subset_of_columns_read) {
             columns.push_back({text_cdef, utf8_type->from_string(*text_val)});
         }
 
-        return std::move(columns);
+        return columns;
     };
 
     assert_that(sst.read_rows_flat())
@@ -2863,7 +2863,7 @@ SEASTAR_THREAD_TEST_CASE(test_uncompressed_collections_read) {
             });
         });
 
-        return std::move(assertions);
+        return assertions;
     };
 
     std::vector<column_id> ids{set_cdef->id, list_cdef->id, map_cdef->id};

tests/top_k_test.cc

@@ -50,7 +50,7 @@ vector<unsigned> count(const utils::space_saving_top_k<unsigned>::results& res)
     for (auto& c : res) {
         v.push_back(c.count);
     }
-    return std::move(v);
+    return v;
 }
 
 //---------------------------------------------------------------------------------------------