package readers import ( "io" "io/ioutil" "testing" "github.com/stretchr/testify/assert" "github.com/stretchr/testify/require" ) func TestPatternReader(t *testing.T) { b2 := make([]byte, 1) r := NewPatternReader(0) b, err := ioutil.ReadAll(r) require.NoError(t, err) assert.Equal(t, []byte{}, b) n, err := r.Read(b2) require.Equal(t, io.EOF, err) require.Equal(t, 0, n) r = NewPatternReader(10) b, err = ioutil.ReadAll(r) require.NoError(t, err) assert.Equal(t, []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}, b) n, err = r.Read(b2) require.Equal(t, io.EOF, err) require.Equal(t, 0, n) } func TestPatternReaderSeek(t *testing.T) { r := NewPatternReader(1024) b, err := ioutil.ReadAll(r) require.NoError(t, err) for i := range b { assert.Equal(t, byte(i%251), b[i]) } n, err := r.Seek(1, io.SeekStart) require.NoError(t, err) assert.Equal(t, int64(1), n) // pos 1 b2 := make([]byte, 10) nn, err := r.Read(b2) require.NoError(t, err) assert.Equal(t, 10, nn) assert.Equal(t, b[1:11], b2) // pos 11 n, err = r.Seek(9, io.SeekCurrent) require.NoError(t, err) assert.Equal(t, int64(20), n) // pos 20 nn, err = r.Read(b2) require.NoError(t, err) assert.Equal(t, 10, nn) assert.Equal(t, b[20:30], b2) n, err = r.Seek(-24, io.SeekEnd) require.NoError(t, err) assert.Equal(t, int64(1000), n) // pos 1000 nn, err = r.Read(b2) require.NoError(t, err) assert.Equal(t, 10, nn) assert.Equal(t, b[1000:1010], b2) // Now test errors n, err = r.Seek(1, 400) require.Error(t, err) assert.Contains(t, err.Error(), "invalid whence") assert.Equal(t, int64(0), n) n, err = r.Seek(-1, io.SeekStart) require.Error(t, err) assert.Contains(t, err.Error(), "negative position") assert.Equal(t, int64(0), n) }