distro/fedoratest: create new testing distribution

The problem with the previous one was that we used artifical image
types, architectures, and distribution but that is not possible any more
because we don't want to use plain strings any more. This commit
introduces a new testing distro which uses proper, existing types.

internal/distro/fedoratest/distro.go

@@ -0,0 +1,62 @@
+package fedoratest
+
+import (
+	"errors"
+	"github.com/osbuild/osbuild-composer/internal/blueprint"
+	"github.com/osbuild/osbuild-composer/internal/common"
+	"github.com/osbuild/osbuild-composer/internal/pipeline"
+	"github.com/osbuild/osbuild-composer/internal/rpmmd"
+)
+
+type FedoraTestDistro struct{}
+
+func New() *FedoraTestDistro {
+	return &FedoraTestDistro{}
+}
+
+func (d *FedoraTestDistro) Name() string {
+	return "fedora-30"
+}
+
+func (d *FedoraTestDistro) Distribution() common.Distribution {
+	return common.Fedora30
+}
+
+func (d *FedoraTestDistro) Repositories(arch string) []rpmmd.RepoConfig {
+	return []rpmmd.RepoConfig{
+		{
+			Id:      "test-id",
+			Name:    "Test Name",
+			BaseURL: "http://example.com/test/os/" + arch,
+		},
+	}
+}
+
+func (d *FedoraTestDistro) ListOutputFormats() []string {
+	return []string{"qcow2"}
+}
+
+func (d *FedoraTestDistro) FilenameFromType(outputFormat string) (string, string, error) {
+	if outputFormat == "qcow2" {
+		return "test.img", "application/x-test", nil
+	} else {
+		return "", "", errors.New("invalid output format: " + outputFormat)
+	}
+}
+
+func (r *FedoraTestDistro) GetSizeForOutputType(outputFormat string, size uint64) uint64 {
+	return 0
+}
+
+func (d *FedoraTestDistro) Pipeline(b *blueprint.Blueprint, additionalRepos []rpmmd.RepoConfig, checksums map[string]string, outputArch, outputFormat string, size uint64) (*pipeline.Pipeline, error) {
+	if outputFormat == "qcow2" && outputArch == "x86_64" {
+		return &pipeline.Pipeline{}, nil
+	} else {
+		return nil, errors.New("invalid output format or arch: " + outputFormat + " @ " + outputArch)
+	}
+}
+
+func (d *FedoraTestDistro) Runner() string {
+	return "org.osbuild.test"
+}
+