Add HW 3

2026-09-24 21:30:37 +03:00
parent 0a1eb51bf8
commit 6210b46c1f
35 changed files with 4012 additions and 0 deletions
@@ -0,0 +1,124 @@
+package hw3test
+
+import (
+	"bytes"
+	"fmt"
+	"github.com/stretchr/testify/require"
+	"io"
+	"math/rand"
+	"os"
+	"path"
+)
+
+// RequireFileContent requires that the contents of the file match the contents of the reader.
+func RequireFileContent(t *TC, workdir, p string, f *EnvFile) {
+	fullpath := path.Join(workdir, p)
+	file, err := os.Open(fullpath)
+	require.NoError(t, err, "failed to open file %s, expected it exists on disk", p)
+	defer file.Close()
+
+	stat, err := file.Stat()
+	require.NoError(t, err, "failed to stat file %s", p)
+	require.Equal(t, f.Size, stat.Size(), "file %s has wrong size", p)
+	require.NoError(t, CompareFileContent(t, file, f), "file %s has wrong content", p)
+}
+
+// CompareFileContent compares first f.Size bytes of the reader with generated content.
+func CompareFileContent(t *TC, r io.Reader, f *EnvFile) error {
+	actual := make([]byte, 64*1024)
+	expected := make([]byte, len(actual))
+	var generator io.Reader
+	if f.TextOnly {
+		generator = f.Open()
+	} else {
+		generator = newComparisonReader(f.GenSeed)
+	}
+	for offset := int64(0); offset < f.Size; {
+		count := int64(len(actual))
+		if remaining := f.Size - offset; remaining < count {
+			count = remaining
+		}
+		if _, err := io.ReadFull(r, actual[:count]); err != nil {
+			return fmt.Errorf("unexpected file error at position %d: %w", offset, err)
+		}
+		if _, err := io.ReadFull(generator, expected[:count]); err != nil {
+			return fmt.Errorf("unexpected generator error at position %d: %w", offset, err)
+		}
+		if !bytes.Equal(actual[:count], expected[:count]) {
+			for i := int64(0); i < count; i++ {
+				if actual[i] != expected[i] {
+					return fmt.Errorf("position %d, expected byte %d, got %d", offset+i, expected[i], actual[i])
+				}
+			}
+		}
+		offset += count
+	}
+
+	return nil
+}
+
+// comparisonReader emits the same bytes as rand.New(source).Read, seven bytes
+// from each Int63 value. It fills complete seven-byte groups without the
+// per-byte branch in math/rand.Read. Request bodies still use EnvFile.Open.
+type comparisonReader struct {
+	source    rand.Source
+	value     uint64
+	remaining uint8
+}
+
+func newComparisonReader(seed int64) *comparisonReader {
+	return &comparisonReader{source: rand.NewSource(seed)}
+}
+
+func (r *comparisonReader) Read(p []byte) (int, error) {
+	n := len(p)
+	for len(p) > 0 && r.remaining > 0 {
+		p[0] = byte(r.value)
+		r.value >>= 8
+		r.remaining--
+		p = p[1:]
+	}
+	for len(p) >= 7 {
+		value := uint64(r.source.Int63())
+		p[0] = byte(value)
+		p[1] = byte(value >> 8)
+		p[2] = byte(value >> 16)
+		p[3] = byte(value >> 24)
+		p[4] = byte(value >> 32)
+		p[5] = byte(value >> 40)
+		p[6] = byte(value >> 48)
+		p = p[7:]
+	}
+	if len(p) > 0 {
+		r.value = uint64(r.source.Int63())
+		r.remaining = 7
+		for i := range p {
+			p[i] = byte(r.value)
+			r.value >>= 8
+			r.remaining--
+		}
+	}
+	return n, nil
+}
+
+// RequireDir ensures that the directory exists on disk.
+func RequireDir(t *TC, workdir string, p string, dir *EnvDir) {
+	fullpath := path.Join(workdir, p)
+	stat, err := os.Stat(fullpath)
+	require.NoError(t, err, "failed to stat directory %s, expected it exists on disk", p)
+	require.True(t, stat.IsDir(), "expected %s to be a directory", p)
+}
+
+// RequireNotExists ensures that the file/directory does not exist on disk.
+func RequireNotExists(t *TC, workdir string, p string) {
+	fullpath := path.Join(workdir, p)
+	_, err := os.Stat(fullpath)
+	require.True(t, os.IsNotExist(err), "expected %s to not exist on disk", p)
+}
+
+// RequireExists ensures that the file/directory exists on disk.
+func RequireExists(t *TC, workdir string, p string) {
+	fullpath := path.Join(workdir, p)
+	_, err := os.Stat(fullpath)
+	require.NoError(t, err, "failed to stat %s, expected it exists on disk", p)
+}