Split tarball progress test from write_test.go (#756)

This example test reaches out to the internet, which isn't ideal.

For now, I'm just going to split it off into a separate file so it's
easier to exclude.

Also, fix some whitespace nits.

Author: jonjohnsonjr

pkg/v1/partial/README.md

@@ -51,7 +51,7 @@ There are some properties of a [`Descriptor`](https://github.com/opencontainers/
 
 For example, in a `tarball.Image`, there is a `LayerSources` field that contains
 an entire layer descriptor with `URLs` information for foreign layers. This
-information can be passed through to callers by implementing this optional 
+information can be passed through to callers by implementing this optional
 `Descriptor` method.
 
 See [`#654`](https://github.com/google/go-containerregistry/pull/654).

pkg/v1/remote/README.md

@@ -8,7 +8,7 @@ per the [OCI distribution spec](https://github.com/opencontainers/distribution-s
 It leans heavily on the lower level [`transport`](/pkg/v1/remote/transport) package, which handles the
 authentication handshake and structured errors.
 
-## Usage 
+## Usage
 
 ```go
 package main

pkg/v1/tarball/progress_test.go

@@ -0,0 +1,89 @@
+// Copyright 2018 Google LLC All Rights Reserved.
+//
+// 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 tarball_test
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+
+	"github.com/google/go-containerregistry/pkg/name"
+	v1 "github.com/google/go-containerregistry/pkg/v1"
+	"github.com/google/go-containerregistry/pkg/v1/remote"
+	"github.com/google/go-containerregistry/pkg/v1/tarball"
+)
+
+func ExampleWithProgress() {
+	/* calculations for this test:
+	The image we are using is docker.io/library/alpine:3.10
+	its size on disk is 2800640
+	The filesizes inside are:
+	-rw-r--r--  0 0      0        1509 Jan  1  1970 sha256:be4e4bea2c2e15b403bb321562e78ea84b501fb41497472e91ecb41504e8a27c
+	-rw-r--r--  0 0      0     2795580 Jan  1  1970 21c83c5242199776c232920ddb58cfa2a46b17e42ed831ca9001c8dbc532d22d.tar.gz
+	-rw-r--r--  0 0      0         216 Jan  1  1970 manifest.json
+	when rounding each to a 512-byte block, plus the header, we get:
+	1509    ->    1536 + 512 = 2048
+	2795580 -> 2796032 + 512 = 2796544
+	216     ->     512 + 512 = 1024
+	add in 2 blocks of all 0x00 to indicate end of archive
+	                         = 1024
+	                        -------
+	Total:                  2800640
+	*/
+	// buffered channel to make the example test easier
+	c := make(chan v1.Update, 200)
+	// Make a tempfile for tarball writes.
+	fp, err := ioutil.TempFile("", "")
+	if err != nil {
+		fmt.Printf("error creating temp file: %v\n", err)
+		return
+	}
+	defer fp.Close()
+	defer os.Remove(fp.Name())
+
+	tag, err := name.NewDigest("docker.io/library/alpine@sha256:f0e9534a598e501320957059cb2a23774b4d4072e37c7b2cf7e95b241f019e35", name.StrictValidation)
+	if err != nil {
+		fmt.Printf("error creating test tag: %v\n", err)
+		return
+	}
+	desc, err := remote.Get(tag)
+	if err != nil {
+		fmt.Printf("error getting manifest: %v", err)
+		return
+	}
+	img, err := desc.Image()
+	if err != nil {
+		fmt.Printf("error image: %v", err)
+		return
+	}
+	go func() {
+		_ = tarball.WriteToFile(fp.Name(), tag, img, tarball.WithProgress(c))
+	}()
+	for update := range c {
+		switch {
+		case update.Error != nil && update.Error == io.EOF:
+			fmt.Fprintf(os.Stderr, "receive error message: %v\n", err)
+			fmt.Printf("%d/%d", update.Complete, update.Total)
+			// Output: 2800640/2800640
+			return
+		case update.Error != nil:
+			fmt.Printf("error writing tarball: %v\n", update.Error)
+			return
+		default:
+			fmt.Fprintf(os.Stderr, "receive update: %#v\n", update)
+		}
+	}
+}

pkg/v1/tarball/write_test.go

@@ -30,7 +30,6 @@ import (
 	v1 "github.com/google/go-containerregistry/pkg/v1"
 	"github.com/google/go-containerregistry/pkg/v1/mutate"
 	"github.com/google/go-containerregistry/pkg/v1/random"
-	"github.com/google/go-containerregistry/pkg/v1/remote"
 	"github.com/google/go-containerregistry/pkg/v1/tarball"
 	"github.com/google/go-containerregistry/pkg/v1/types"
 	"github.com/google/go-containerregistry/pkg/v1/validate"
@@ -485,65 +484,3 @@ func getLayersFilenames(hashes []string) []string {
 	}
 	return filenames
 }
-
-func ExampleWithProgress() {
-	/* calculations for this test:
-	The image we are using is docker.io/library/alpine:3.10
-	its size on disk is 2800640
-	The filesizes inside are:
-	-rw-r--r--  0 0      0        1509 Jan  1  1970 sha256:be4e4bea2c2e15b403bb321562e78ea84b501fb41497472e91ecb41504e8a27c
-	-rw-r--r--  0 0      0     2795580 Jan  1  1970 21c83c5242199776c232920ddb58cfa2a46b17e42ed831ca9001c8dbc532d22d.tar.gz
-	-rw-r--r--  0 0      0         216 Jan  1  1970 manifest.json
-	when rounding each to a 512-byte block, plus the header, we get:
-	1509    ->    1536 + 512 = 2048
-	2795580 -> 2796032 + 512 = 2796544
-	216     ->     512 + 512 = 1024
-	add in 2 blocks of all 0x00 to indicate end of archive
-	                         = 1024
-	                        -------
-	Total:                  2800640
-	*/
-	// buffered channel to make the example test easier
-	c := make(chan v1.Update, 200)
-	// Make a tempfile for tarball writes.
-	fp, err := ioutil.TempFile("", "")
-	if err != nil {
-		fmt.Printf("error creating temp file: %v\n", err)
-		return
-	}
-	defer fp.Close()
-	defer os.Remove(fp.Name())
-
-	tag, err := name.NewDigest("docker.io/library/alpine@sha256:f0e9534a598e501320957059cb2a23774b4d4072e37c7b2cf7e95b241f019e35", name.StrictValidation)
-	if err != nil {
-		fmt.Printf("error creating test tag: %v\n", err)
-		return
-	}
-	desc, err := remote.Get(tag)
-	if err != nil {
-		fmt.Printf("error getting manifest: %v", err)
-		return
-	}
-	img, err := desc.Image()
-	if err != nil {
-		fmt.Printf("error image: %v", err)
-		return
-	}
-	go func() {
-		_ = tarball.WriteToFile(fp.Name(), tag, img, tarball.WithProgress(c))
-	}()
-	for update := range c {
-		switch {
-		case update.Error != nil && update.Error == io.EOF:
-			fmt.Fprintf(os.Stderr, "receive error message: %v\n", err)
-			fmt.Printf("%d/%d", update.Complete, update.Total)
-			// Output: 2800640/2800640
-			return
-		case update.Error != nil:
-			fmt.Printf("error writing tarball: %v\n", update.Error)
-			return
-		default:
-			fmt.Fprintf(os.Stderr, "receive update: %#v\n", update)
-		}
-	}
-}