diff --git a/src/box/errcode.h b/src/box/errcode.h
index 96bbf06f76fe426472966773ce90554d6cc8b1b5..1dde7c6dfd8f1d86e2e890e50079c6950abd75cb 100644
--- a/src/box/errcode.h
+++ b/src/box/errcode.h
@@ -288,7 +288,7 @@ struct errcode_record {
 	/*233 */_(ER_TUPLE_FIELD_COUNT_LIMIT,	"Tuple field count limit reached: see box.schema.FIELD_MAX") \
 	/*234 */_(ER_CREATE_CONSTRAINT,		"Failed to create constraint '%s' in space '%s': %s") \
 	/*235 */_(ER_FIELD_CONSTRAINT_FAILED,	"Check constraint '%s' failed for field '%s'") \
-	/*236 */_(ER_TUPLE_CONSTRAINT_FAILED,	"Check constraint '%s' failed for tuple") \
+	/*236 */_(ER_TUPLE_CONSTRAINT_FAILED,	"Check constraint '%s' failed for a tuple") \
 	/*237 */_(ER_CREATE_FOREIGN_KEY,	"Failed to create foreign key '%s' in space '%s': %s") \
 	/*238 */_(ER_FOREIGN_KEY_INTEGRITY,	"Foreign key '%s' integrity check failed: %s") \
 	/*239 */_(ER_FIELD_FOREIGN_KEY_FAILED,	"Foreign key constraint '%s' failed for field '%s': %s") \
diff --git a/test/box/net.box_iproto_transactions_over_streams.result b/test/box/net.box_iproto_transactions_over_streams.result
index a5a2d3dc998f95144df5afe2f775582aeec853e5..8e5986417ead7d1a737b1fb37598d714f8079ed8 100644
--- a/test/box/net.box_iproto_transactions_over_streams.result
+++ b/test/box/net.box_iproto_transactions_over_streams.result
@@ -1541,10 +1541,10 @@ true_check_res = monster_ddl_check()
 true_check_res
 ---
 - - 'Finished ok, errors and trigger catcher content: '
-  - Check constraint 'CK1' failed for tuple
+  - Check constraint 'CK1' failed for a tuple
   - Duplicate key exists in unique index "unique_unnamed_T2_2" in space "T2" with
     old tuple - [1, 1, 1] and new tuple - [2, 2, 1]
-  - Check constraint 'CK2' failed for tuple
+  - Check constraint 'CK2' failed for a tuple
   - metadata:
     - name: ID
       type: integer
diff --git a/test/engine-luatest/gh_6436_tuple_constraint_test.lua b/test/engine-luatest/gh_6436_tuple_constraint_test.lua
index a7961c5675060896389e0be2a664882a74a43c70..eae1fde95c164a32d325c1a048d90b2f4f072576 100644
--- a/test/engine-luatest/gh_6436_tuple_constraint_test.lua
+++ b/test/engine-luatest/gh_6436_tuple_constraint_test.lua
@@ -64,11 +64,11 @@ g.test_tuple_constraint_basics = function(cg)
 
             t.assert_equals(s:replace{1, 2, 3, field4}, {1, 2, 3, field4})
             t.assert_error_msg_content_equals(
-                "Check constraint 'tuple_constr1' failed for tuple",
+                "Check constraint 'tuple_constr1' failed for a tuple",
                 function() s:replace{100, 2, 3, field4} end
             )
             t.assert_error_msg_content_equals(
-                "Check constraint 'tuple_constr1' failed for tuple",
+                "Check constraint 'tuple_constr1' failed for a tuple",
                 function() s:replace{1, 200, 3, field4} end
             )
             t.assert_equals(s:select{}, {{1, 2, 3, field4}})
@@ -81,10 +81,10 @@ g.test_tuple_constraint_basics = function(cg)
         local s = c.space.test
         t.assert_equals(s:replace{1, 2, 3, field4}, {1, 2, 3, field4})
         t.assert_error_msg_content_equals(
-            "Check constraint 'tuple_constr1' failed for tuple",
+            "Check constraint 'tuple_constr1' failed for a tuple",
             function() s:replace{100, 2, 3, field4} end)
         t.assert_error_msg_content_equals(
-            "Check constraint 'tuple_constr1' failed for tuple",
+            "Check constraint 'tuple_constr1' failed for a tuple",
             function() s:replace{1, 200, 3, field4} end)
         t.assert_equals(s:select{}, {{1, 2, 3, field4}})
      end
@@ -321,15 +321,15 @@ g.test_several_tuple_constraints = function(cg)
 
             t.assert_equals(s:replace{1, 2, 3, field4}, {1, 2, 3, field4})
             t.assert_error_msg_content_equals(
-                "Check constraint 'check1' failed for tuple",
+                "Check constraint 'check1' failed for a tuple",
                 function() s:replace{100, 2, 3, field4} end
             )
             t.assert_error_msg_content_equals(
-                "Check constraint 'check2' failed for tuple",
+                "Check constraint 'check2' failed for a tuple",
                 function() s:replace{1, 200, 3, field4} end
             )
             t.assert_error_msg_content_equals(
-                "Check constraint 'check2' failed for tuple",
+                "Check constraint 'check2' failed for a tuple",
                 function() s:replace{1, 2, 300, field4} end
             )
             t.assert_equals(s:select{}, {{1, 2, 3, field4}})
@@ -342,13 +342,13 @@ g.test_several_tuple_constraints = function(cg)
         local s = c.space.test
         t.assert_equals(s:replace{1, 2, 3, field4}, {1, 2, 3, field4})
         t.assert_error_msg_content_equals(
-            "Check constraint 'check1' failed for tuple",
+            "Check constraint 'check1' failed for a tuple",
             function() s:replace{100, 2, 3, field4} end)
         t.assert_error_msg_content_equals(
-            "Check constraint 'check2' failed for tuple",
+            "Check constraint 'check2' failed for a tuple",
             function() s:replace{1, 200, 3, field4} end)
         t.assert_error_msg_content_equals(
-            "Check constraint 'check2' failed for tuple",
+            "Check constraint 'check2' failed for a tuple",
             function() s:replace{1, 2, 300, field4} end)
         t.assert_equals(s:select{}, {{1, 2, 3, field4}})
      end
@@ -437,7 +437,7 @@ g.test_tuple_constraint_integrity = function(cg)
         t.assert_equals(s.constraint, {tuple_constr1 = box.func.tuple_constr1.id})
         t.assert_equals(s:replace{1, 2, 3}, {1, 2, 3})
         t.assert_error_msg_content_equals(
-            "Check constraint 'tuple_constr1' failed for tuple",
+            "Check constraint 'tuple_constr1' failed for a tuple",
             function() s:replace{100, 2, 3} end
         )
     end, {engine})
@@ -476,18 +476,18 @@ g.test_tuple_constraint_integrity = function(cg)
 
         t.assert_equals(s:replace{100, 2, 3}, {100, 2, 3})
         t.assert_error_msg_content_equals(
-            "Check constraint 'check2' failed for tuple",
+            "Check constraint 'check2' failed for a tuple",
             function() s:replace{1, 200, 3} end
         )
         t.assert_equals(s:replace{1, 2, 300}, {1, 2, 300})
 
         t.assert_error_msg_content_equals(
-            "Check constraint 'check3' failed for tuple",
+            "Check constraint 'check3' failed for a tuple",
             function() s:alter{constraint = {check2='tuple_constr2',
                                              check3='tuple_constr3'}} end
         )
         t.assert_error_msg_content_equals(
-            "Check constraint 'check2' failed for tuple",
+            "Check constraint 'check2' failed for a tuple",
             function() s:replace{1, 200, 3} end
         )
 
diff --git a/test/engine-luatest/gh_6986_c_constraint_test.lua b/test/engine-luatest/gh_6986_c_constraint_test.lua
index 6ec808fbfee3113b43dbdb221457e7077c714c6c..8079ae2c1850436800911683e4eb409de9071390 100644
--- a/test/engine-luatest/gh_6986_c_constraint_test.lua
+++ b/test/engine-luatest/gh_6986_c_constraint_test.lua
@@ -26,7 +26,7 @@ g.test_c_constraint = function(cg)
         s:alter{constraint='gh_6986.get_check'}
         t.assert_equals(s:insert{1}, {1})
         t.assert_error_msg_content_equals(
-            "Check constraint 'gh_6986.get_check' failed for tuple",
+            "Check constraint 'gh_6986.get_check' failed for a tuple",
             function() s:insert{2} end
         )
         s:drop()
diff --git a/test/engine-luatest/gh_7339_drop_fk_in_same_txn_test.lua b/test/engine-luatest/gh_7339_drop_fk_in_same_txn_test.lua
index 90272d988c650609099e08175fce7377718cfdcd..676ea7e46ebbd0044912252eb975cbce58f869c8 100644
--- a/test/engine-luatest/gh_7339_drop_fk_in_same_txn_test.lua
+++ b/test/engine-luatest/gh_7339_drop_fk_in_same_txn_test.lua
@@ -94,7 +94,7 @@ g.test_constraints_alter_in_txn = function(cg)
         a:replace{10, 10}
         b:replace{10, 10}
         a:insert{0, 0}
-        msg = "Check constraint 'ck1' failed for tuple"
+        msg = "Check constraint 'ck1' failed for a tuple"
         t.assert_error_msg_content_equals(msg, b.insert, b, {0, 0})
         a:insert{30, 30}
         msg = "Check constraint 'ck2' failed for field '1 (i)'"
diff --git a/test/engine-luatest/gh_7645_ck_fk_constraints_test.lua b/test/engine-luatest/gh_7645_ck_fk_constraints_test.lua
index 8817234a477adda61125b03e6c174d71baf1d8a2..e881f7d03308c22ce924edbe4eb41dd580df0429 100644
--- a/test/engine-luatest/gh_7645_ck_fk_constraints_test.lua
+++ b/test/engine-luatest/gh_7645_ck_fk_constraints_test.lua
@@ -93,7 +93,7 @@ g.test_tuple_ck_fk_constraints = function(cg)
             function() user:replace({2, 99, 'Bob'}) end
         )
         t.assert_error_msg_content_equals(
-            "Check constraint 'check' failed for tuple",
+            "Check constraint 'check' failed for a tuple",
             function() user:replace{2, 100, 'Bob'} end
         )
     end, {engine})
diff --git a/test/sql-luatest/constraint_test.lua b/test/sql-luatest/constraint_test.lua
index 2f35ab32431bcd2b69af5cc490449fa8db98b36b..430089ac2e4d8ef9d7dd8d6588ca7c25ff130e5e 100644
--- a/test/sql-luatest/constraint_test.lua
+++ b/test/sql-luatest/constraint_test.lua
@@ -534,15 +534,18 @@ g.test_constraints_11 = function()
         box.execute([[CREATE TABLE t(i INT PRIMARY KEY,
                                      CONSTRAINT one CHECK (i > 10));]])
         local _, err = box.execute([[INSERT INTO t VALUES (1);]])
-        t.assert_equals(err.message, "Check constraint 'ONE' failed for tuple")
+        t.assert_equals(err.message,
+                        "Check constraint 'ONE' failed for a tuple")
         _, err = box.execute([[ALTER TABLE t DISABLE CHECK CONSTRAINT one;]])
         t.assert_equals(err.message, "Syntax error at line 1 near 'DISABLE'")
         _, err = box.execute([[INSERT INTO t VALUES (1);]])
-        t.assert_equals(err.message, "Check constraint 'ONE' failed for tuple")
+        t.assert_equals(err.message,
+                        "Check constraint 'ONE' failed for a tuple")
         _, err = box.execute([[ALTER TABLE t ENABLE CHECK CONSTRAINT one;]])
         t.assert_equals(err.message, "Syntax error at line 1 near 'ENABLE'")
         _, err = box.execute([[INSERT INTO t VALUES (1);]])
-        t.assert_equals(err.message, "Check constraint 'ONE' failed for tuple")
+        t.assert_equals(err.message,
+                        "Check constraint 'ONE' failed for a tuple")
 
         box.execute([[DROP TABLE t;]])
     end)
diff --git a/test/sql-luatest/datetime_test.lua b/test/sql-luatest/datetime_test.lua
index 041a809ec3cece2a8ea9b6091160c0e308530891..96c95932bd04a7bfe44f366e80024fe7d6054e90 100644
--- a/test/sql-luatest/datetime_test.lua
+++ b/test/sql-luatest/datetime_test.lua
@@ -263,7 +263,7 @@ g.test_datetime_12 = function()
                       CAST(dt as STRING) != '2001-01-01T01:00:00Z'));]])
 
         local sql = [[INSERT INTO t SELECT * from t1 LIMIT 1;]]
-        local res = [[Check constraint 'CK' failed for tuple]]
+        local res = [[Check constraint 'CK' failed for a tuple]]
         local _, err = box.execute(sql)
         box.execute([[DROP TABLE t;]])
 
diff --git a/test/sql-luatest/interval_test.lua b/test/sql-luatest/interval_test.lua
index 47f40ce11c02787247b57fc8271b71d8ea2761da..2e36d3a07334d9c65ab2a86333ce83e6e634a894 100644
--- a/test/sql-luatest/interval_test.lua
+++ b/test/sql-luatest/interval_test.lua
@@ -143,7 +143,7 @@ g.test_interval_10 = function()
                       '+1 years, 2 months, 3 days, 4 hours'));]])
 
         local sql = [[INSERT INTO t SELECT * from t0 LIMIT 1;]]
-        local res = [[Check constraint 'CK' failed for tuple]]
+        local res = [[Check constraint 'CK' failed for a tuple]]
         local _, err = box.execute(sql)
         box.execute([[DROP TABLE t;]])
 
diff --git a/test/sql-luatest/sql_func_expr_test.lua b/test/sql-luatest/sql_func_expr_test.lua
index 5fa1eb4f3595cee1df218c4900227482b9b24e96..a0c35cf0311b7ba0b2436374bf79832388aeca82 100644
--- a/test/sql-luatest/sql_func_expr_test.lua
+++ b/test/sql-luatest/sql_func_expr_test.lua
@@ -24,11 +24,11 @@ g.test_sql_func_expr_1 = function()
         s:alter{constraint='abc'}
         t.assert_equals(s:insert{3, 4}, {3, 4})
         t.assert_error_msg_content_equals(
-            "Check constraint 'abc' failed for tuple",
+            "Check constraint 'abc' failed for a tuple",
             function() s:insert{1, 2} end
         )
         t.assert_error_msg_content_equals(
-            "Check constraint 'abc' failed for tuple",
+            "Check constraint 'abc' failed for a tuple",
             function() s:insert{true, 2} end
         )
         box.space.test:drop()
@@ -101,7 +101,7 @@ g.test_sql_func_expr_3 = function()
         s:create_index('i')
         s:alter{constraint='abc'}
         t.assert_error_msg_content_equals(
-            "Check constraint 'abc' failed for tuple",
+            "Check constraint 'abc' failed for a tuple",
             function() s:insert{1, 1} end
         )
     end)
@@ -109,7 +109,7 @@ g.test_sql_func_expr_3 = function()
     g.server:exec(function()
         t.assert_equals(box.func.abc.language, 'SQL_EXPR')
         t.assert_error_msg_content_equals(
-            "Check constraint 'abc' failed for tuple",
+            "Check constraint 'abc' failed for a tuple",
             function() box.space.test:insert{2, 2} end
         )
         t.assert_equals(box.space.test:insert{7, 7}, {7, 7})
@@ -130,7 +130,7 @@ g.test_sql_func_expr_4 = function()
         s:alter{constraint='abc'}
         t.assert_equals(s:insert{3, 4}, {3, 4})
         t.assert_error_msg_content_equals(
-            "Check constraint 'abc' failed for tuple",
+            "Check constraint 'abc' failed for a tuple",
             function() s:insert{1, 2} end
         )
         box.space.test:drop()
@@ -150,7 +150,7 @@ g.test_sql_func_expr_4 = function()
         s:alter{constraint='abc'}
         t.assert_equals(s:insert{3, 4}, {3, 4})
         t.assert_error_msg_content_equals(
-            "Check constraint 'abc' failed for tuple",
+            "Check constraint 'abc' failed for a tuple",
             function() s:insert{1, 2} end
         )
         box.space.test:drop()
diff --git a/test/sql-tap/alter2.test.lua b/test/sql-tap/alter2.test.lua
index 94390f0e9601525ec2edaff5b7e397436762d588..8cd2d88a128257a58b8c957cea8a89f888167a06 100755
--- a/test/sql-tap/alter2.test.lua
+++ b/test/sql-tap/alter2.test.lua
@@ -224,7 +224,7 @@ test:do_catchsql_test(
         CREATE TABLE t1 (id INT PRIMARY KEY);
         ALTER TABLE t1 ADD CONSTRAINT ck CHECK(id > 0);
         INSERT INTO t1 VALUES (-1);
-    ]], { 1, "Check constraint 'CK' failed for tuple" })
+    ]], { 1, "Check constraint 'CK' failed for a tuple" })
 
 -- Make sure that one can't create constraint with the same name twice.
 --
diff --git a/test/sql-tap/check.test.lua b/test/sql-tap/check.test.lua
index 8c065e0ff5f3eab780078bd62b5810a70773d727..bf6bb0c20c42a33f436a92aa9ccfa7ebfc99181b 100755
--- a/test/sql-tap/check.test.lua
+++ b/test/sql-tap/check.test.lua
@@ -55,7 +55,7 @@ test:do_catchsql_test(
         INSERT INTO t1 VALUES(6,7, 2);
     ]], {
         -- <check-1.3>
-        1, "Check constraint 'ck_unnamed_T1_1' failed for tuple"
+        1, "Check constraint 'ck_unnamed_T1_1' failed for a tuple"
         -- </check-1.3>
     })
 
@@ -75,7 +75,7 @@ test:do_catchsql_test(
         INSERT INTO t1 VALUES(4,3, 2);
     ]], {
         -- <check-1.5>
-        1, "Check constraint 'ck_unnamed_T1_2' failed for tuple"
+        1, "Check constraint 'ck_unnamed_T1_2' failed for a tuple"
         -- </check-1.5>
     })
 
@@ -95,7 +95,7 @@ test:do_catchsql_test(
         INSERT INTO t1 VALUES(NULL,6, 4);
     ]], {
         -- <check-1.7>
-        1, "Check constraint 'ck_unnamed_T1_1' failed for tuple"
+        1, "Check constraint 'ck_unnamed_T1_1' failed for a tuple"
         -- </check-1.7>
     })
 
@@ -115,7 +115,7 @@ test:do_catchsql_test(
         INSERT INTO t1 VALUES(2,NULL, 5);
     ]], {
         -- <check-1.9>
-        1, "Check constraint 'ck_unnamed_T1_2' failed for tuple"
+        1, "Check constraint 'ck_unnamed_T1_2' failed for a tuple"
         -- </check-1.9>
     })
 
@@ -147,7 +147,7 @@ test:do_catchsql_test(
         UPDATE t1 SET x=7 WHERE x==2
     ]], {
         -- <check-1.12>
-        1, "Check constraint 'ck_unnamed_T1_1' failed for tuple"
+        1, "Check constraint 'ck_unnamed_T1_1' failed for a tuple"
         -- </check-1.12>
     })
 
@@ -167,7 +167,7 @@ test:do_catchsql_test(
         UPDATE t1 SET x=5 WHERE x==2
     ]], {
         -- <check-1.14>
-        1, "Check constraint 'ck_unnamed_T1_1' failed for tuple"
+        1, "Check constraint 'ck_unnamed_T1_1' failed for a tuple"
         -- </check-1.14>
     })
 
@@ -349,7 +349,7 @@ test:do_catchsql_test(
         INSERT INTO t3 VALUES(111,222,333);
     ]], {
         -- <check-3.9>
-        1, "Check constraint 'ck_unnamed_T3_1' failed for tuple"
+        1, "Check constraint 'ck_unnamed_T3_1' failed for a tuple"
         -- </check-3.9>
     })
 
@@ -420,7 +420,7 @@ test:do_catchsql_test(
         UPDATE t4 SET x=0, y=1;
     ]], {
         -- <check-4.6>
-        1, "Check constraint 'ck_unnamed_T4_1' failed for tuple"
+        1, "Check constraint 'ck_unnamed_T4_1' failed for a tuple"
         -- </check-4.6>
     })
 
@@ -440,7 +440,7 @@ test:do_catchsql_test(
         UPDATE t4 SET x=0, y=2;
     ]], {
         -- <check-4.9>
-        1, "Check constraint 'ck_unnamed_T4_1' failed for tuple"
+        1, "Check constraint 'ck_unnamed_T4_1' failed for a tuple"
         -- </check-4.9>
     })
 
@@ -517,7 +517,7 @@ test:do_catchsql_test(
         UPDATE OR FAIL t1 SET x=7-x, y=y+1;
     ]], {
         -- <check-6.5>
-        1, "Check constraint 'ck_unnamed_T1_1' failed for tuple"
+        1, "Check constraint 'ck_unnamed_T1_1' failed for a tuple"
         -- </check-6.5>
     })
 
@@ -539,7 +539,7 @@ test:do_catchsql_test(
         INSERT OR ROLLBACK INTO t1 VALUES(8,40.0, 10);
     ]], {
         -- <check-6.7>
-        1, "Check constraint 'ck_unnamed_T1_1' failed for tuple"
+        1, "Check constraint 'ck_unnamed_T1_1' failed for a tuple"
         -- </check-6.7>
     })
 
@@ -572,7 +572,7 @@ test:do_catchsql_test(
         REPLACE INTO t1 VALUES(6,7, 11);
     ]], {
         -- <check-6.12>
-        1, "Check constraint 'ck_unnamed_T1_1' failed for tuple"
+        1, "Check constraint 'ck_unnamed_T1_1' failed for a tuple"
         -- </check-6.12>
     })
 
diff --git a/test/sql-tap/decimal.test.lua b/test/sql-tap/decimal.test.lua
index a9bafaf739f0b1b8c9be9e926289948739214576..998a1ce4cc73cc73daccce238b39df472972c0e7 100755
--- a/test/sql-tap/decimal.test.lua
+++ b/test/sql-tap/decimal.test.lua
@@ -199,7 +199,7 @@ test:do_catchsql_test(
     [[
         INSERT INTO t5c SELECT 1, u FROM t2 LIMIT 1;
     ]], {
-        1, "Check constraint 'CK' failed for tuple"
+        1, "Check constraint 'CK' failed for a tuple"
     })
 
 test:do_execsql_test(
diff --git a/test/sql-tap/table.test.lua b/test/sql-tap/table.test.lua
index 6a2d536b0259da509b550e8da589ffb1026f54b2..3fdb7c081808e9c4caa39baf8222196a54597a4a 100755
--- a/test/sql-tap/table.test.lua
+++ b/test/sql-tap/table.test.lua
@@ -1176,7 +1176,7 @@ test:do_catchsql_test(
         INSERT INTO T21 VALUES(2, -1, 1);
     ]], {
         -- <table-21.3>
-        1, "Check constraint 'ck_unnamed_T21_1' failed for tuple"
+        1, "Check constraint 'ck_unnamed_T21_1' failed for a tuple"
         -- </table-21.3>
     })
 
@@ -1327,7 +1327,7 @@ test:do_catchsql_test(
         INSERT INTO T28 VALUES(0);
     ]], {
         -- <table-22.10>
-        1, "Check constraint 'CHECK1' failed for tuple"
+        1, "Check constraint 'CHECK1' failed for a tuple"
         -- </table-22.10>
     })
 
@@ -1337,7 +1337,7 @@ test:do_catchsql_test(
         INSERT INTO T28 VALUES(9);
     ]], {
         -- <table-22.11>
-        1, "Check constraint 'CHECK2' failed for tuple"
+        1, "Check constraint 'CHECK2' failed for a tuple"
         -- </table-22.11>
     })
 
diff --git a/test/sql-tap/uuid.test.lua b/test/sql-tap/uuid.test.lua
index 966830b9fef868532d3a31c5d1947557818242bf..623538c8f0901c44c4de25da6fd360e311b3335c 100755
--- a/test/sql-tap/uuid.test.lua
+++ b/test/sql-tap/uuid.test.lua
@@ -192,7 +192,7 @@ test:do_catchsql_test(
     [[
         INSERT INTO t5c SELECT 1, u FROM t2 LIMIT 1;
     ]], {
-        1, "Check constraint 'CK' failed for tuple"
+        1, "Check constraint 'CK' failed for a tuple"
     })
 
 test:do_execsql_test(
diff --git a/test/sql/boolean.result b/test/sql/boolean.result
index a038f416a0bf7c3c2c4cfac827878e8af0d71a4d..804f0954375ca4188adf4b05314b3fbc420da8cb 100644
--- a/test/sql/boolean.result
+++ b/test/sql/boolean.result
@@ -436,7 +436,7 @@ INSERT INTO t1 VALUES (1, false);
 INSERT INTO t1 VALUES (2, true);
  | ---
  | - null
- | - Check constraint 'CK' failed for tuple
+ | - Check constraint 'CK' failed for a tuple
  | ...
 
 -- Check interactions with FOREIGN KEY constraint.
diff --git a/test/sql/gh-2981-check-autoinc.result b/test/sql/gh-2981-check-autoinc.result
index 123976d713f2ddbe8b3454185c5de531bd82bc2d..c6bd366eeeed9831c8e57f6a722e10287f63ed9c 100644
--- a/test/sql/gh-2981-check-autoinc.result
+++ b/test/sql/gh-2981-check-autoinc.result
@@ -29,7 +29,7 @@ box.execute("insert into t1 values (18, null);")
 box.execute("insert into t1(s2) values (null);")
 ---
 - null
-- Check constraint 'ck_unnamed_T1_1' failed for tuple
+- Check constraint 'ck_unnamed_T1_1' failed for a tuple
 ...
 box.execute("insert into t2 values (18, null);")
 ---
@@ -38,7 +38,7 @@ box.execute("insert into t2 values (18, null);")
 box.execute("insert into t2(s2) values (null);")
 ---
 - null
-- Check constraint 'ck_unnamed_T2_1' failed for tuple
+- Check constraint 'ck_unnamed_T2_1' failed for a tuple
 ...
 box.execute("insert into t2 values (24, null);")
 ---
@@ -47,7 +47,7 @@ box.execute("insert into t2 values (24, null);")
 box.execute("insert into t2(s2) values (null);")
 ---
 - null
-- Check constraint 'ck_unnamed_T2_1' failed for tuple
+- Check constraint 'ck_unnamed_T2_1' failed for a tuple
 ...
 box.execute("insert into t3 values (9, null)")
 ---
@@ -56,7 +56,7 @@ box.execute("insert into t3 values (9, null)")
 box.execute("insert into t3(s2) values (null)")
 ---
 - null
-- Check constraint 'ck_unnamed_T3_1' failed for tuple
+- Check constraint 'ck_unnamed_T3_1' failed for a tuple
 ...
 box.execute("DROP TABLE t1")
 ---