adding encoding extension

cargo/extension_config.go

@@ -36,10 +36,10 @@ type ConfigExtensionMetadataDependency struct {
 }
 type ConfigExtensionMetadataConfiguration struct {
 	Default     string `toml:"default"          json:"default,omitempty"`
-	Description string `toml:"description"	    json:"description,omitempty"`
-	Launch      bool   `toml:"launch"	        json:"launch,omitempty"`
+	Launch      bool   `toml:"launch"           json:"launch,omitempty"`
+	Description string `toml:"description"      json:"description,omitempty"`
+	Build       bool   `toml:"build"            json:"build,omitempty"`
 	Name        string `toml:"name"             json:"name,omitempty"`
-	Build       bool   `toml:"build"	        json:"build,omitempty"`
 }
 type ConfigExtension struct {
 	ID          string                   `toml:"id"                    json:"id,omitempty"`

cargo/extension_config_test.go

@@ -1,20 +1,127 @@
 package cargo_test
 
 import (
+	"bytes"
+
 	"strings"
 	"testing"
 
 	"github.com/paketo-buildpacks/packit/v2/cargo"
 	"github.com/sclevine/spec"
 
 	. "github.com/onsi/gomega"
+	. "github.com/paketo-buildpacks/packit/v2/matchers"
 )
 
 func testExtensionConfig(t *testing.T, context spec.G, it spec.S) {
 	var (
 		Expect = NewWithT(t).Expect
+		buffer *bytes.Buffer
 	)
 
+	it.Before(func() {
+		buffer = bytes.NewBuffer(nil)
+	})
+
+	context("EncodeConfig", func() {
+		it("encodes the config to TOML", func() {
+
+			err := cargo.EncodeExtensionConfig(buffer, cargo.ExtensionConfig{
+				API: "0.7",
+				Extension: cargo.ConfigExtension{
+					ID:          "some-extension-id",
+					Name:        "some-extension-name",
+					Version:     "some-extension-version",
+					Homepage:    "some-extension-homepage",
+					Description: "some-extension-description",
+					Keywords:    []string{"some-extension-keyword"},
+					Licenses: []cargo.ConfigExtensionLicense{
+						{
+							Type: "some-license-type",
+							URI:  "some-license-uri",
+						},
+					},
+				},
+				Metadata: cargo.ConfigExtensionMetadata{
+					IncludeFiles: []string{
+						"some-include-file",
+						"other-include-file",
+					},
+					PrePackage: "some-pre-package-script.sh",
+					Dependencies: []cargo.ConfigExtensionMetadataDependency{
+						{
+							Checksum:       "sha256:some-sum",
+							ID:             "some-dependency",
+							Licenses:       []interface{}{"fancy-license", "fancy-license-2"},
+							Name:           "Some Dependency",
+							SHA256:         "shasum",
+							Source:         "source",
+							SourceChecksum: "sha256:source-shasum",
+							SourceSHA256:   "source-shasum",
+							Stacks:         []string{"io.buildpacks.stacks.bionic", "org.cloudfoundry.stacks.tiny"},
+							URI:            "http://some-url",
+							Version:        "1.2.3",
+						},
+					},
+					Configurations: []cargo.ConfigExtensionMetadataConfiguration{
+						{
+							Default:     "0",
+							Description: "some-metadata-configuration-description",
+							Launch:      true,
+							Name:        "SOME_METADATA_CONFIGURATION_NAME",
+							Build:       true,
+						},
+					},
+					DefaultVersions: map[string]string{
+						"some-dependency": "1.2.x",
+					},
+				},
+			})
+			Expect(err).NotTo(HaveOccurred())
+			Expect(buffer.String()).To(MatchTOML(`
+api = "0.7"
+
+[extension]
+  description = "some-extension-description"
+  homepage = "some-extension-homepage"
+  id = "some-extension-id"
+  keywords = ["some-extension-keyword"]
+  name = "some-extension-name"
+  version = "some-extension-version"
+
+  [[extension.licenses]]
+    type = "some-license-type"
+    uri = "some-license-uri"
+
+[metadata]
+  include-files = ["some-include-file", "other-include-file"]
+  pre-package = "some-pre-package-script.sh"
+
+  [[metadata.configurations]]
+    build = true
+    description = "some-metadata-configuration-description"
+    launch = true
+    default = "0"
+    name = "SOME_METADATA_CONFIGURATION_NAME"
+  [metadata.default-versions]
+    some-dependency = "1.2.x"
+
+  [[metadata.dependencies]]
+    checksum = "sha256:some-sum"
+    id = "some-dependency"
+    licenses = ["fancy-license", "fancy-license-2"]
+    name = "Some Dependency"
+    sha256 = "shasum"
+    source = "source"
+    source-checksum = "sha256:source-shasum"
+    source_sha256 = "source-shasum"
+    stacks = ["io.buildpacks.stacks.bionic", "org.cloudfoundry.stacks.tiny"]
+    uri = "http://some-url"
+    version = "1.2.3"
+`))
+		})
+	})
+
 	context("DecodeExtensionConfig", func() {
 		it("decodes TOML to Extensionconfig", func() {
 			tomlBuffer := strings.NewReader(`
@@ -39,9 +146,6 @@ keywords = [ "some-extension-keyword" ]
 [metadata.default-versions]
 	some-dependency = "1.2.x"
 
-[[metadata.some-map]]
-	key = "value"
-
 [[metadata.dependencies]]
 	checksum = "sha256:some-sum"
 	id = "some-dependency"