cipd/client/cipd/pkg/source_test.go

// Copyright 2021 The LUCI Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package pkg

import (
	"bytes"
	"io"
	"testing"

	. "github.com/smartystreets/goconvey/convey"
)

func TestReadSeekerSource(t *testing.T) {
	t.Parallel()

	Convey("With buffer", t, func() {
		src, err := NewReadSeekerSource(bytes.NewReader([]byte("12345")))
		So(err, ShouldBeNil)
		So(src.Size(), ShouldEqual, 5)

		buf := make([]byte, 2)

		Convey("Sequential reads", func() {
			n, err := src.ReadAt(buf, 0)
			So(err, ShouldBeNil)
			So(n, ShouldEqual, 2)
			So(buf, ShouldResemble, []byte("12"))

			n, err = src.ReadAt(buf, 2)
			So(err, ShouldBeNil)
			So(n, ShouldEqual, 2)
			So(buf, ShouldResemble, []byte("34"))

			n, err = src.ReadAt(buf, 4)
			So(err, ShouldBeNil)
			So(n, ShouldEqual, 1)
			So(buf[:1], ShouldResemble, []byte("5"))

			n, err = src.ReadAt(buf, 5)
			So(err, ShouldEqual, io.EOF)
			So(n, ShouldEqual, 0)
		})

		Convey("Random reads", func() {
			n, err := src.ReadAt(buf, 4)
			So(err, ShouldBeNil)
			So(n, ShouldEqual, 1)
			So(buf[:1], ShouldResemble, []byte("5"))

			n, err = src.ReadAt(buf, 0)
			So(err, ShouldBeNil)
			So(n, ShouldEqual, 2)
			So(buf, ShouldResemble, []byte("12"))

			// Again.
			n, err = src.ReadAt(buf, 0)
			So(err, ShouldBeNil)
			So(n, ShouldEqual, 2)
			So(buf, ShouldResemble, []byte("12"))

			n, err = src.ReadAt(buf, 5)
			So(err, ShouldEqual, io.EOF)
			So(n, ShouldEqual, 0)

			n, err = src.ReadAt(buf, 6)
			So(err, ShouldEqual, io.EOF)
			So(n, ShouldEqual, 0)
		})

		Convey("Negative offset", func() {
			n, err := src.ReadAt(buf, -1)
			So(err, ShouldNotBeNil)
			So(n, ShouldEqual, 0)
		})
	})
}