Create parition info parsing library

to be used both here (when trying to find the partition UUID using a
label) and on the kairos side when updating the file after calling
kcrypt to encrypt a partition (which causes the UUID to change).

Signed-off-by: Dimitris Karakasilis <dimitris@karakasilis.me>

pkg/partition_info/partition_info_test.go

@@ -0,0 +1,102 @@
+package partition_info_test
+
+import (
+	"io/ioutil"
+	"os"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+
+	pi "github.com/kairos-io/kcrypt/pkg/partition_info"
+)
+
+var _ = Describe("Partition Info file parsing", func() {
+	Describe("ParsePartitionInfoFile", func() {
+		var file string
+
+		BeforeEach(func() {
+			file = "../../tests/assets/partition_info.yaml"
+		})
+
+		It("parses the file correctly", func() {
+			info, err := pi.ParsePartitionInfoFile(file)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(len(info)).To(Equal(2))
+			Expect(info["COS_PERSISTENT"]).To(Equal("some_uuid_1"))
+			Expect(info["COS_OTHER"]).To(Equal("some_uuid_2"))
+		})
+	})
+
+	Describe("UpdatePartitionInfoFile", func() {
+		var file *os.File
+		var err error
+
+		BeforeEach(func() {
+			file, err = ioutil.TempFile("", "parition-info.*.yaml")
+			Expect(err).ToNot(HaveOccurred())
+
+			fileContents := `
+- label: TO_DELETE
+  uuid: old_uuid_1
+- label: TO_BE_UPDATED
+  uuid: old_uuid_2
+`
+			_, err = file.Write([]byte(fileContents))
+			Expect(err).ToNot(HaveOccurred())
+		})
+
+		AfterEach(func() {
+			os.Remove(file.Name())
+		})
+
+		It("Updates the partition file correctly", func() {
+			partitionInfo := pi.PartitionInfo{
+				"TO_BE_UPDATED": "new_uuid_1",
+				"NEW_PARTITION": "new_uuid_2",
+			}
+
+			err = pi.UpdatePartitionInfoFile(partitionInfo, file.Name())
+			Expect(err).ToNot(HaveOccurred())
+
+			dat, err := os.ReadFile(file.Name())
+			Expect(err).ToNot(HaveOccurred())
+
+			expectedContent := `NEW_PARTITION: new_uuid_2
+TO_BE_UPDATED: new_uuid_1
+`
+			Expect(string(dat)).To(Equal(expectedContent))
+		})
+	})
+
+	Describe("UpdatePartitionLabelMapping", func() {
+		var file *os.File
+		var err error
+
+		BeforeEach(func() {
+			file, err = ioutil.TempFile("", "parition-info.*.yaml")
+			Expect(err).ToNot(HaveOccurred())
+
+			_, err = file.Write([]byte("TO_KEEP: old_uuid_1"))
+			Expect(err).ToNot(HaveOccurred())
+		})
+
+		AfterEach(func() {
+			os.Remove(file.Name())
+		})
+
+		It("Updates the file correctly from a `kcrypt encrypt` return value", func() {
+			partitionData := "TO_BE_ADDED:some_name:new_uuid"
+
+			err = pi.UpdatePartitionLabelMapping(partitionData, file.Name())
+			Expect(err).ToNot(HaveOccurred())
+
+			dat, err := os.ReadFile(file.Name())
+			Expect(err).ToNot(HaveOccurred())
+
+			expectedContent := `TO_BE_ADDED: new_uuid
+TO_KEEP: old_uuid_1
+`
+			Expect(string(dat)).To(Equal(expectedContent))
+		})
+	})
+})