Add test for part count check

test/tuple_keydef.test.lua

@@ -241,7 +241,7 @@ local tuple_keydef_new_cases = {
 
 local test = tap.test('tuple.keydef')
 
-test:plan(#tuple_keydef_new_cases - 1 + 8)
+test:plan(#tuple_keydef_new_cases - 1 + 8 + 1)
 for _, case in ipairs(tuple_keydef_new_cases) do
     if type(case) == 'function' then
         case()
@@ -604,4 +604,26 @@ test:test('JSON path is not supported error', function(test)
                    'verify error message')
 end)
 
+-- Copied from tarantool proper
+test:test('key_def part count tests', function(test)
+	test:plan(3)
+
+    local kd = tuple_keydef.new({{fieldno = 1, type = 'unsigned'}})
+    local ok, res
+
+    -- Should succeed
+    ok, res = pcall(kd.compare_with_key, kd, {1}, {1})
+    test:ok(ok and res == 0, "Simple equality")
+
+    -- Should succeed
+    ok, res = pcall(kd.compare_with_key, kd, {1}, {2})
+    test:ok(ok and res < 0, "Simple inequality")
+
+    -- Should fail
+    local exp_err = "Invalid key part count (expected [0..1], got 9)"
+    ok, res = pcall(kd.compare_with_key, kd, {1}, {1, 2, 3, 4, 5, 6, 7, 8, 9})
+    test:is_deeply({ok, tostring(res)}, {false, exp_err},
+        "Invalid key part count")
+end)
+
 os.exit(test:check() and 0 or 1)