add big int json test cases

Author: dtunikov

flow/e2e/clickhouse_mysql_test.go

@@ -295,18 +295,28 @@ func (s ClickHouseSuite) Test_MySQL_JSON_SnapshotCDCConsistency() {
 			js json NOT NULL
 		)`, srcFullName)))
 
-	variants := []string{
-		`{"z": 1, "aa": 2}`,                         // key order: shorter key sorts after longer one
-		`{"b": 2, "a": 1}`,                          // key order: reversed on storage
-		`{"n": [3, 1, 2], "obj": {"y": 1, "x": 2}}`, // nested object key order + array order preserved
-		`{"s": "a, b: c"}`,                          // whitespace inside strings is preserved
-		`{"pi": 3.14, "half": 0.5, "neg": -2.5}`,    // non-whole doubles that render identically in both paths
+	variants := []struct {
+		val         string
+		expectExact string
+	}{
+		{val: `{"z": 1, "aa": 2}`},                                                                // key order: shorter key sorts after longer one
+		{val: `{"b": 2, "a": 1}`},                                                                 // key order: reversed on storage
+		{val: `{"n": [3, 1, 2], "obj": {"y": 1, "x": 2}}`},                                        // nested object key order + array order preserved
+		{val: `{"s": "a, b: c"}`},                                                                 // whitespace inside strings is preserved
+		{val: `{"pi": 3.14, "half": 0.5, "neg": -2.5}`},                                           // non-whole doubles that render identically in both paths
+		{val: `{"big": 1234567890123456789}`, expectExact: `{"big":1234567890123456789}`},         // 19-digit int64: float64 rounds to ...6800
+		{val: `{"maxsafe": 9007199254740993}`, expectExact: `{"maxsafe":9007199254740993}`},       // 2^53+1: float64 drops the low bit (...992)
+		{val: `{"negbig": -1234567890123456789}`, expectExact: `{"negbig":-1234567890123456789}`}, // sign preserved at full precision
+		{
+			val:         `{"mix": [1234567890123456789, -9007199254740993, 9007199254740993]}`, // same hazards inside an array
+			expectExact: `{"mix":[1234567890123456789,-9007199254740993,9007199254740993]}`,
+		},
 	}
 
 	insertVariants := func() {
 		for _, v := range variants {
 			require.NoError(s.t, s.source.Exec(s.t.Context(),
-				fmt.Sprintf(`INSERT INTO %s (js) VALUES ('%s')`, srcFullName, v)))
+				fmt.Sprintf(`INSERT INTO %s (js) VALUES ('%s')`, srcFullName, v.val)))
 		}
 	}
 
@@ -340,7 +350,11 @@ func (s ClickHouseSuite) Test_MySQL_JSON_SnapshotCDCConsistency() {
 	for i := range variants {
 		snapshotGot := fmt.Sprint(rows.Records[i][1].Value())
 		cdcGot := fmt.Sprint(rows.Records[i+len(variants)][1].Value())
-		require.Equal(s.t, snapshotGot, cdcGot, "snapshot/cdc JSON representation differs for %q", variants[i])
+		require.Equal(s.t, snapshotGot, cdcGot, "snapshot/cdc JSON representation differs for %q", variants[i].val)
+		if variants[i].expectExact != "" {
+			require.Equal(s.t, variants[i].expectExact, snapshotGot, "snapshot JSON not preserved faithfully for %q", variants[i].val)
+			require.Equal(s.t, variants[i].expectExact, cdcGot, "cdc JSON not preserved faithfully for %q", variants[i].val)
+		}
 	}
 
 	env.Cancel(s.t.Context())