add test check page

Signed-off-by: Mustafa Elbehery <melbeher@redhat.com>

Author: Elbehery

tx_test.go

@@ -2,8 +2,11 @@ package bbolt_test
 
 import (
 	"bytes"
+	"encoding/binary"
 	"errors"
 	"fmt"
+	"go.etcd.io/bbolt/internal/common"
+	"go.etcd.io/bbolt/internal/guts_cli"
 	"log"
 	"os"
 	"runtime"
@@ -18,6 +21,107 @@ import (
 	"go.etcd.io/bbolt/internal/btesting"
 )
 
+func TestTx_Check_Page(t *testing.T) {
+	bucketKey := "testBucket"
+	db := btesting.MustCreateDBWithOption(t, &bolt.Options{PageSize: pageSize})
+	defer db.MustDeleteFile()
+
+	// arrange
+	if err := db.Update(func(tx *bolt.Tx) error {
+		b, err := tx.CreateBucketIfNotExists([]byte(bucketKey))
+		if err != nil {
+			t.Fatal(err)
+		}
+		// insert random data
+		for i := 0; i < 10; i++ {
+			generateSampleDataInBucket(t, b, 3)
+		}
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+	db.MustCheck()
+
+	// act : corrupt a leaf page
+	corruptLeafPageFromDB(t, db.Path())
+
+	// assert: expected an error after check
+	if err := db.View(func(tx *bolt.Tx) error {
+		for err := range tx.Check() {
+			fmt.Println(err)
+		}
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+	db.MustClose()
+}
+
+func corruptLeafPageFromDB(t testing.TB, dbPath string) {
+	_, hwm, err := guts_cli.ReadPageAndHWMSize(dbPath)
+	if err != nil {
+		t.Fatalf("error reading HWM from dbPath %v: %v", dbPath, err)
+	}
+
+	var victimPage *common.Page
+	var victimBuf []byte
+
+	// find first leaf page starting page after root bucket's page
+	for pageID := uint64(4); pageID < uint64(hwm); {
+		p, buf, err := guts_cli.ReadPage(dbPath, pageID)
+		if err != nil {
+			t.Fatalf("error reading page %v from dbPath %v: %v", pageID, dbPath, err)
+		}
+
+		if p.IsLeafPage() {
+			victimPage = p
+			victimBuf = buf
+			break
+		}
+	}
+
+	if victimPage == nil || victimBuf == nil {
+		t.Fatalf("no leaf page is found in dbPath %v", dbPath)
+	}
+
+	// corrupt page's type
+	invalidLPE := common.NewLeafPageElement(0, 0, 0, 0)
+	var buf bytes.Buffer
+	binary.Write(&buf, binary.BigEndian, invalidLPE)
+	copy(victimBuf[17:], buf.Bytes())
+	// write page back to file
+	err = guts_cli.WritePage(dbPath, victimBuf)
+	if err != nil {
+		t.Errorf("error writing victim page %v back to dbpath %v: %v", victimPage.Id(), dbPath, err)
+	}
+}
+
+// generateSampleDataInBucket fill in sample data into given bucket to create the given
+// number of leafPages. To control the number of leafPages, sample data are generated in order.
+func generateSampleDataInBucket(t testing.TB, bk *bolt.Bucket, lPages int) {
+	currentKey := 1
+	currentVal := 100
+	for i := 0; i < lPages; i++ {
+
+		currentSize := pageHeaderSize
+		for currentSize < pageSize {
+			err := bk.Put(convertIntIntoBytes(t, currentKey), convertIntIntoBytes(t, currentVal))
+			require.NoError(t, err)
+			currentSize += 16 + 4 + 4
+		}
+
+		currentKey++
+		currentVal++
+	}
+}
+
+func convertIntIntoBytes(t testing.TB, i int) []byte {
+	t.Helper()
+	buf := make([]byte, 4)
+	binary.BigEndian.PutUint32(buf, uint32(i))
+	return buf
+}
+
 // TestTx_Check_ReadOnly tests consistency checking on a ReadOnly database.
 func TestTx_Check_ReadOnly(t *testing.T) {
 	db := btesting.MustCreateDB(t)