Finished tests for the store.

internal/log/store_test.go

@@ -1,6 +1,8 @@
 package log
 
 import (
+	"io/ioutil"
+	"os"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -11,10 +13,110 @@ var (
 	width = uint64(len(write) + lenWidth)
 )
 
+func TestStoreAppendRead(t *testing.T) {
+	// Create a temprorary file with a random name.
+	f, err := ioutil.TempFile("", "store_append_read_test")
+	require.NoError(t, err)
+	defer os.Remove(f.Name())
+
+	// Create a new store from the file.
+	s, err := newStore(f)
+	require.NoError(t, err)
+
+	// Basic operations.
+	testAppend(t, s)
+	testRead(t, s)
+	testReadAt(t, s)
+
+	// A store can be created from an existing non-empty file.
+	s, err = newStore(f)
+	require.NoError(t, err)
+	testRead(t, s)
+}
+
 func testAppend(t *testing.T, s *store) {
 	t.Helper()
 	for i := uint64(1); i < 4; i++ {
 		n, pos, err := s.Append(write)
 		require.NoError(t, err)
+		// test the returned offsets.
+		require.Equal(t, width*i, pos+n)
 	}
 }
+
+func testRead(t *testing.T, s *store) {
+	t.Helper()
+	var pos uint64
+	for i := uint64(1); i < 4; i++ {
+		read, err := s.Read(pos)
+		require.NoError(t, err)
+		require.Equal(t, write, read)
+		pos += width
+	}
+}
+
+func testReadAt(t *testing.T, s *store) {
+	t.Helper()
+	for i, off := uint64(1), int64(0); i < 4; i++ {
+		// Read the size of the record at the current offset.
+		b := make([]byte, lenWidth)
+		n, err := s.File.ReadAt(b, off)
+		require.NoError(t, err)
+		// bytes read same as predifined byte size for length.
+		require.Equal(t, lenWidth, n)
+		off += int64(n)
+
+		// Read the actual content of the record.
+		size := enc.Uint64(b)
+		b = make([]byte, size)
+		n, err = s.ReadAt(b, off)
+		require.NoError(t, err)
+		// Read the correct number of bytes.
+		require.Equal(t, int(size), n)
+		// The content read is correct.
+		require.Equal(t, write, b)
+		off += int64(n)
+	}
+}
+
+func TestStoreClose(t *testing.T) {
+	f, err := ioutil.TempFile("", "store_close_test")
+	require.NoError(t, err)
+	defer os.Remove(f.Name())
+
+	s, err := newStore(f)
+	require.NoError(t, err)
+
+	// Append a single record.
+	_, _, err = s.Append(write)
+	require.NoError(t, err)
+
+	_, beforeSize, err := openFile(f.Name())
+	require.NoError(t, err)
+
+	err = s.Close()
+	require.NoError(t, err)
+
+	_, afterSize, err := openFile(f.Name())
+	require.NoError(t, err)
+
+	// A store buffers its writes so the size of the underlying file should change after close.
+	require.Greater(t, afterSize, beforeSize)
+
+}
+
+func openFile(name string) (file *os.File, size int64, err error) {
+	f, err := os.OpenFile(
+		name,
+		os.O_RDWR|os.O_CREATE|os.O_APPEND,
+		0644,
+	)
+	if err != nil {
+		return nil, 0, err
+	}
+	fi, err := f.Stat()
+	if err != nil {
+		return nil, 0, err
+	}
+	return f, fi.Size(), nil
+}