Added pm.Meta

meta.go

@@ -0,0 +1,23 @@
+package pm
+
+import "errors"
+
+type Meta struct {
+	Name        string `json:"name"`
+	Version     string `json:"version"`
+	Description string `json:"description"`
+	Namespace   string `json:"namespace"`
+}
+
+func (m *Meta) Valid() (bool, error) {
+	if m.Name == "" {
+		return false, errors.New("name cannot be empty")
+	}
+	if m.Version == "" {
+		return false, errors.New("version cannot be empty")
+	}
+	if m.Description == "" {
+		return false, errors.New("description cannot be empty")
+	}
+	return true, nil
+}

meta_test.go

@@ -0,0 +1,96 @@
+package pm
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"testing"
+)
+
+func TestValid(t *testing.T) {
+	tests := []struct {
+		label string
+		m     Meta
+		ok    bool
+		err   error
+	}{
+		{
+			label: "valid",
+			m: Meta{
+				Name:        "heat",
+				Version:     "1.1.0",
+				Description: "some description",
+			},
+			ok: true,
+		},
+		{
+			label: "valid with namespace",
+			m: Meta{
+				Name:        "heat",
+				Version:     "1.1.0",
+				Description: "some description",
+				Namespace:   "some/namespace",
+			},
+			ok: true,
+		},
+		{
+			label: "missing name",
+			m: Meta{
+				Version:     "1.1.0",
+				Description: "some description",
+			},
+			err: errors.New("name"),
+		},
+		{
+			label: "missing version",
+			m: Meta{
+				Name:        "heat",
+				Description: "some description",
+			},
+			err: errors.New("version"),
+		},
+		{
+			label: "missing description",
+			m: Meta{
+				Name:    "heat",
+				Version: "1.1.0",
+			},
+			err: errors.New("description"),
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.label, func(t *testing.T) {
+			ok, err := test.m.Valid()
+			if got, want := ok, test.ok; got != want {
+				t.Fatalf("validity: got %v, want %v", got, want)
+			}
+
+			if got, want := err, test.err; (err == nil) != (test.err == nil) {
+				t.Fatalf("error: got %v, want %v", got, want)
+			}
+		})
+	}
+}
+
+func TestJsonRoundTrip(t *testing.T) {
+	b := Meta{
+		Name:        "heat",
+		Version:     "1.1.0",
+		Description: "make heat using cpus",
+		Namespace:   "/darwin/amd64",
+	}
+
+	buf := &bytes.Buffer{}
+	if err := json.NewEncoder(buf).Encode(&b); err != nil {
+		t.Fatalf("encode: %v", err)
+	}
+
+	a := Meta{}
+	if err := json.NewDecoder(buf).Decode(&a); err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	if b != a {
+		t.Fatalf("a != b: %v != %v", a, b)
+	}
+}