* querylog: add test

internal/querylog/qlog_file.go

@@ -42,8 +42,7 @@ type QLogFile struct {
 
 // NewQLogFile initializes a new instance of the QLogFile
 func NewQLogFile(path string) (*QLogFile, error) {
-	f, err := os.OpenFile(path, os.O_RDONLY, 0644)
-
+	f, err := os.OpenFile(path, os.O_RDONLY, 0o644)
 	if err != nil {
 		return nil, err
 	}
@@ -232,7 +231,7 @@ func (q *QLogFile) readNextLine(position int64) (string, int64, error) {
 
 	// Look for the end of the prev line
 	// This is where we'll read from
-	var startLine = int64(0)
+	startLine := int64(0)
 	for i := relativePos - 1; i >= 0; i-- {
 		if q.buffer[i] == '\n' {
 			startLine = i + 1
@@ -298,15 +297,15 @@ func (q *QLogFile) readProbeLine(position int64) (string, int64, int64, error) {
 
 	// Now start looking for the new line character starting
 	// from the relativePos and going left
-	var startLine = int64(0)
+	startLine := int64(0)
 	for i := relativePos - 1; i >= 0; i-- {
 		if buffer[i] == '\n' {
 			startLine = i + 1
 			break
 		}
 	}
 	// Looking for the end of line now
-	var endLine = int64(bufferLen)
+	endLine := int64(bufferLen)
 	lineEndIdx := endLine + seekPosition
 	for i := relativePos; i < int64(bufferLen); i++ {
 		if buffer[i] == '\n' {

internal/querylog/qlog_file_test.go

@@ -288,3 +288,32 @@ func TestQLogSeek(t *testing.T) {
 	assert.Nil(t, err)
 	assert.Equal(t, 1, depth)
 }
+
+func TestQLogSeek_ErrEndOfLog(t *testing.T) {
+	testDir := prepareTestDir()
+	t.Cleanup(func() {
+		_ = os.RemoveAll(testDir)
+	})
+
+	d := `{"T":"2020-08-31T18:44:23.911246629+03:00","QH":"wfqvjymurpwegyv","QT":"A","QC":"IN","CP":"","Answer":"","Result":{},"Elapsed":66286385,"Upstream":"tls://dns-unfiltered.adguard.com:853"}
+{"T":"2020-08-31T18:44:25.376690873+03:00"}
+{"T":"2020-08-31T18:44:25.382540454+03:00"}
+`
+	f, err := ioutil.TempFile(testDir, "*.txt")
+	assert.Nil(t, err)
+	defer f.Close()
+
+	_, err = f.WriteString(d)
+	assert.Nil(t, err)
+
+	q, err := NewQLogFile(f.Name())
+	assert.Nil(t, err)
+	defer q.Close()
+
+	target, err := time.Parse(time.RFC3339, "2020-08-31T18:44:25.382540454+03:00")
+	assert.Nil(t, err)
+
+	_, depth, err := q.Seek(target.UnixNano() + int64(time.Second))
+	assert.Equal(t, ErrEndOfLog, err)
+	assert.Equal(t, 2, depth)
+}