Pull request: * all: move internal Go packages to internal/

Merge in DNS/adguard-home from 2234-move-to-internal to master

Squashed commit of the following:

commit d26a288cabeac86f9483fab307677b1027c78524
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Fri Oct 30 12:44:18 2020 +0300

    * all: move internal Go packages to internal/

    Closes #2234.

internal/querylog/qlog_reader_test.go

@@ -0,0 +1,157 @@
+package querylog
+
+import (
+	"io"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestQLogReaderEmpty(t *testing.T) {
+	r, err := NewQLogReader([]string{})
+	assert.Nil(t, err)
+	assert.NotNil(t, r)
+	defer r.Close()
+
+	// seek to the start
+	err = r.SeekStart()
+	assert.Nil(t, err)
+
+	line, err := r.ReadNext()
+	assert.Equal(t, "", line)
+	assert.Equal(t, io.EOF, err)
+}
+
+func TestQLogReaderOneFile(t *testing.T) {
+	// let's do one small file
+	count := 10
+	filesCount := 1
+
+	testDir := prepareTestDir()
+	defer func() { _ = os.RemoveAll(testDir) }()
+	testFiles := prepareTestFiles(testDir, filesCount, count)
+
+	r, err := NewQLogReader(testFiles)
+	assert.Nil(t, err)
+	assert.NotNil(t, r)
+	defer r.Close()
+
+	// seek to the start
+	err = r.SeekStart()
+	assert.Nil(t, err)
+
+	// read everything
+	read := 0
+	var line string
+	for err == nil {
+		line, err = r.ReadNext()
+		if err == nil {
+			assert.True(t, len(line) > 0)
+			read += 1
+		}
+	}
+
+	assert.Equal(t, count*filesCount, read)
+	assert.Equal(t, io.EOF, err)
+}
+
+func TestQLogReaderMultipleFiles(t *testing.T) {
+	// should be large enough
+	count := 10000
+	filesCount := 5
+
+	testDir := prepareTestDir()
+	defer func() { _ = os.RemoveAll(testDir) }()
+	testFiles := prepareTestFiles(testDir, filesCount, count)
+
+	r, err := NewQLogReader(testFiles)
+	assert.Nil(t, err)
+	assert.NotNil(t, r)
+	defer r.Close()
+
+	// seek to the start
+	err = r.SeekStart()
+	assert.Nil(t, err)
+
+	// read everything
+	read := 0
+	var line string
+	for err == nil {
+		line, err = r.ReadNext()
+		if err == nil {
+			assert.True(t, len(line) > 0)
+			read += 1
+		}
+	}
+
+	assert.Equal(t, count*filesCount, read)
+	assert.Equal(t, io.EOF, err)
+}
+
+func TestQLogReaderSeek(t *testing.T) {
+	// more or less big file
+	count := 10000
+	filesCount := 2
+
+	testDir := prepareTestDir()
+	defer func() { _ = os.RemoveAll(testDir) }()
+	testFiles := prepareTestFiles(testDir, filesCount, count)
+
+	r, err := NewQLogReader(testFiles)
+	assert.Nil(t, err)
+	assert.NotNil(t, r)
+	defer r.Close()
+
+	// CASE 1: NOT TOO OLD LINE
+	testSeekLineQLogReader(t, r, 300)
+
+	// CASE 2: OLD LINE
+	testSeekLineQLogReader(t, r, count-300)
+
+	// CASE 3: FIRST LINE
+	testSeekLineQLogReader(t, r, 0)
+
+	// CASE 4: LAST LINE
+	testSeekLineQLogReader(t, r, count)
+
+	// CASE 5: Seek non-existent (too low)
+	err = r.Seek(123)
+	assert.NotNil(t, err)
+
+	// CASE 6: Seek non-existent (too high)
+	ts, _ := time.Parse(time.RFC3339, "2100-01-02T15:04:05Z07:00")
+	err = r.Seek(ts.UnixNano())
+	assert.NotNil(t, err)
+}
+
+func testSeekLineQLogReader(t *testing.T, r *QLogReader, lineNumber int) {
+	line, err := getQLogReaderLine(r, lineNumber)
+	assert.Nil(t, err)
+	ts := readQLogTimestamp(line)
+	assert.NotEqual(t, uint64(0), ts)
+
+	// try seeking to that line now
+	err = r.Seek(ts)
+	assert.Nil(t, err)
+
+	testLine, err := r.ReadNext()
+	assert.Nil(t, err)
+	assert.Equal(t, line, testLine)
+}
+
+func getQLogReaderLine(r *QLogReader, lineNumber int) (string, error) {
+	err := r.SeekStart()
+	if err != nil {
+		return "", err
+	}
+
+	for i := 1; i < lineNumber; i++ {
+		_, err := r.ReadNext()
+		if err != nil {
+			return "", err
+		}
+	}
+	return r.ReadNext()
+}