added a custom flag type for the instances flag option in scale

- added the types package
- added NullInt type to distinguish between user provided and default
values

[#148649153]

Signed-off-by: Nick Wei <[email protected]>

Author: mariash

command/flag/instances.go

@@ -0,0 +1,21 @@
+package flag
+
+import (
+	"code.cloudfoundry.org/cli/types"
+	flags "github.com/jessevdk/go-flags"
+)
+
+type Instances struct {
+	types.NullInt
+}
+
+func (i *Instances) UnmarshalFlag(val string) error {
+	err := i.ParseFlagValue(val)
+	if err != nil || i.Value < 0 {
+		return &flags.Error{
+			Type:    flags.ErrRequired,
+			Message: "invalid argument for flag '-i' (expected int > 0)",
+		}
+	}
+	return nil
+}

command/flag/instances_test.go

@@ -0,0 +1,53 @@
+package flag_test
+
+import (
+	. "code.cloudfoundry.org/cli/command/flag"
+	"code.cloudfoundry.org/cli/types"
+	flags "github.com/jessevdk/go-flags"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("Instances", func() {
+	var instances Instances
+
+	Describe("UnmarshalFlag", func() {
+		Context("when the empty string is provided", func() {
+			It("sets IsSet to false", func() {
+				err := instances.UnmarshalFlag("")
+				Expect(err).ToNot(HaveOccurred())
+				Expect(instances).To(Equal(Instances{types.NullInt{Value: 0, IsSet: false}}))
+			})
+		})
+
+		Context("when an invalid integer is provided", func() {
+			It("returns an error", func() {
+				err := instances.UnmarshalFlag("abcdef")
+				Expect(err).To(MatchError(&flags.Error{
+					Type:    flags.ErrRequired,
+					Message: "invalid argument for flag '-i' (expected int > 0)",
+				}))
+				Expect(instances).To(Equal(Instances{types.NullInt{Value: 0, IsSet: false}}))
+			})
+		})
+
+		Context("when a negative integer is provided", func() {
+			It("returns an error", func() {
+				err := instances.UnmarshalFlag("-10")
+				Expect(err).To(MatchError(&flags.Error{
+					Type:    flags.ErrRequired,
+					Message: "invalid argument for flag '-i' (expected int > 0)",
+				}))
+				Expect(instances).To(Equal(Instances{types.NullInt{Value: -10, IsSet: true}}))
+			})
+		})
+
+		Context("when a valid integer is provided", func() {
+			It("stores the integer and sets IsSet to true", func() {
+				err := instances.UnmarshalFlag("0")
+				Expect(err).ToNot(HaveOccurred())
+				Expect(instances).To(Equal(Instances{types.NullInt{Value: 0, IsSet: true}}))
+			})
+		})
+	})
+})

types/null_int.go

@@ -0,0 +1,24 @@
+package types
+
+import "strconv"
+
+type NullInt struct {
+	Value int
+	IsSet bool
+}
+
+func (n *NullInt) ParseFlagValue(val string) error {
+	if val == "" {
+		return nil
+	}
+
+	intVal, err := strconv.Atoi(val)
+	if err != nil {
+		return err
+	}
+
+	n.Value = intVal
+	n.IsSet = true
+
+	return nil
+}

types/null_int_test.go

@@ -0,0 +1,37 @@
+package types_test
+
+import (
+	. "code.cloudfoundry.org/cli/types"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("NullInt", func() {
+	var nullInt NullInt
+
+	Describe("ParseFlagValue", func() {
+		Context("when the empty string is provided", func() {
+			It("sets IsSet to false", func() {
+				err := nullInt.ParseFlagValue("")
+				Expect(err).ToNot(HaveOccurred())
+				Expect(nullInt).To(Equal(NullInt{Value: 0, IsSet: false}))
+			})
+		})
+
+		Context("when an invalid integer is provided", func() {
+			It("returns an error", func() {
+				err := nullInt.ParseFlagValue("abcdef")
+				Expect(err).To(HaveOccurred())
+				Expect(nullInt).To(Equal(NullInt{Value: 0, IsSet: false}))
+			})
+		})
+
+		Context("when a valid integer is provided", func() {
+			It("stores the integer and sets IsSet to true", func() {
+				err := nullInt.ParseFlagValue("0")
+				Expect(err).ToNot(HaveOccurred())
+				Expect(nullInt).To(Equal(NullInt{Value: 0, IsSet: true}))
+			})
+		})
+	})
+})

types/types_suite_test.go

@@ -0,0 +1,13 @@
+package types_test
+
+import (
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+
+	"testing"
+)
+
+func TestTypes(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Types Suite")
+}