fix: upload from local image generates broken command (#98)

While adding support for qcow2 images in #69 I broke support for local
images. Building a shell pipeline through string concatenation is not a
good idea...

The specific issue was fixed and I also moved building the shell
pipeline to a separate function and added unit tests for all cases, so
it should be easier to spot these issues in the future.

Closes #97

hcloudimages/client_test.go

@@ -1,33 +1,110 @@
-package hcloudimages_test
+package hcloudimages
 
 import (
-	"context"
-	"fmt"
 	"net/url"
-
-	"github.com/hetznercloud/hcloud-go/v2/hcloud"
-
-	"github.com/apricote/hcloud-upload-image/hcloudimages"
+	"testing"
 )
 
-func ExampleClient_Upload() {
-	client := hcloudimages.NewClient(
-		hcloud.NewClient(hcloud.WithToken("<your token>")),
-	)
-
-	imageURL, err := url.Parse("https://example.com/disk-image.raw.bz2")
+func mustParseURL(s string) *url.URL {
+	u, err := url.Parse(s)
 	if err != nil {
 		panic(err)
 	}
 
-	image, err := client.Upload(context.TODO(), hcloudimages.UploadOptions{
-		ImageURL:         imageURL,
-		ImageCompression: hcloudimages.CompressionBZ2,
-		Architecture:     hcloud.ArchitectureX86,
-	})
-	if err != nil {
-		panic(err)
-	}
-
-	fmt.Printf("Uploaded Image: %d", image.ID)
+	return u
+}
+
+func TestAssembleCommand(t *testing.T) {
+	tests := []struct {
+		name    string
+		options UploadOptions
+		want    string
+		wantErr bool
+	}{
+		{
+			name:    "local raw",
+			options: UploadOptions{},
+			want:    "bash -c 'set -euo pipefail && dd of=/dev/sda bs=4M && sync'",
+		},
+		{
+			name: "remote raw",
+			options: UploadOptions{
+				ImageURL: mustParseURL("https://example.com/image.xz"),
+			},
+			want: "bash -c 'set -euo pipefail && wget --no-verbose -O - \"https://example.com/image.xz\" | dd of=/dev/sda bs=4M && sync'",
+		},
+		{
+			name: "local xz",
+			options: UploadOptions{
+				ImageCompression: CompressionXZ,
+			},
+			want: "bash -c 'set -euo pipefail && xz -cd | dd of=/dev/sda bs=4M && sync'",
+		},
+		{
+			name: "remote xz",
+			options: UploadOptions{
+				ImageURL:         mustParseURL("https://example.com/image.xz"),
+				ImageCompression: CompressionXZ,
+			},
+			want: "bash -c 'set -euo pipefail && wget --no-verbose -O - \"https://example.com/image.xz\" | xz -cd | dd of=/dev/sda bs=4M && sync'",
+		},
+		{
+			name: "local bz2",
+			options: UploadOptions{
+				ImageCompression: CompressionBZ2,
+			},
+			want: "bash -c 'set -euo pipefail && bzip2 -cd | dd of=/dev/sda bs=4M && sync'",
+		},
+		{
+			name: "remote bz2",
+			options: UploadOptions{
+				ImageURL:         mustParseURL("https://example.com/image.bz2"),
+				ImageCompression: CompressionXZ,
+			},
+			want: "bash -c 'set -euo pipefail && wget --no-verbose -O - \"https://example.com/image.bz2\" | xz -cd | dd of=/dev/sda bs=4M && sync'",
+		},
+		{
+			name: "local qcow2",
+			options: UploadOptions{
+				ImageFormat: FormatQCOW2,
+			},
+			want: "bash -c 'set -euo pipefail && tee image.qcow2 > /dev/null && qemu-img dd -f qcow2 -O raw if=image.qcow2 of=/dev/sda bs=4M && sync'",
+		},
+		{
+			name: "remote qcow2",
+			options: UploadOptions{
+				ImageURL:    mustParseURL("https://example.com/image.qcow2"),
+				ImageFormat: FormatQCOW2,
+			},
+			want: "bash -c 'set -euo pipefail && wget --no-verbose -O - \"https://example.com/image.qcow2\" | tee image.qcow2 > /dev/null && qemu-img dd -f qcow2 -O raw if=image.qcow2 of=/dev/sda bs=4M && sync'",
+		},
+
+		{
+			name: "unknown compression",
+			options: UploadOptions{
+				ImageCompression: "noodle",
+			},
+			wantErr: true,
+		},
+
+		{
+			name: "unknown format",
+			options: UploadOptions{
+				ImageFormat: "poodle",
+			},
+			wantErr: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := assembleCommand(tt.options)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("assembleCommand() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if got != tt.want {
+				t.Errorf("assembleCommand() got = %v, want %v", got, tt.want)
+			}
+		})
+	}
 }