Add package to calculate and compare artifact checksums

Refers to #28

pkg/compiler/checksum_test.go

@@ -0,0 +1,54 @@
+// Copyright © 2019 Ettore Di Giacinto <mudler@gentoo.org>
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along
+// with this program; if not, see <http://www.gnu.org/licenses/>.
+
+package compiler_test
+
+import (
+	"io/ioutil"
+	"os"
+
+	. "github.com/mudler/luet/pkg/compiler"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("Checksum", func() {
+	Context("Generation", func() {
+		It("Compares successfully", func() {
+
+			tmpdir, err := ioutil.TempDir("", "tree")
+			Expect(err).ToNot(HaveOccurred())
+			defer os.RemoveAll(tmpdir) // clean up
+			buildsum := Checksums{}
+			definitionsum := Checksums{}
+			definitionsum2 := Checksums{}
+
+			err = buildsum.Generate(NewPackageArtifact("../../tests/fixtures/layers/alpine/build.yaml"))
+			Expect(err).ToNot(HaveOccurred())
+
+			err = definitionsum.Generate(NewPackageArtifact("../../tests/fixtures/layers/alpine/definition.yaml"))
+			Expect(err).ToNot(HaveOccurred())
+
+			err = definitionsum2.Generate(NewPackageArtifact("../../tests/fixtures/layers/alpine/definition.yaml"))
+			Expect(err).ToNot(HaveOccurred())
+
+			Expect(definitionsum.Compare(buildsum)).To(HaveOccurred())
+			Expect(definitionsum.Compare(definitionsum2)).ToNot(HaveOccurred())
+
+		})
+	})
+
+})