Add unit test for cloudformation usecase

app/domain/model/cloudformation.go

@@ -13,6 +13,11 @@ const (
 // StackStatus is the status of a CloudFormation stack.
 type StackStatus string
 
+// String returns the string representation of StackStatus.
+func (s StackStatus) String() string {
+	return string(s)
+}
+
 // CloudFormation stack status constants
 // Ref. https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-describing-stacks.html
 const (

app/external/mock/cloudformation.go

@@ -0,0 +1,15 @@
+package mock
+
+import (
+	"context"
+
+	"github.com/nao1215/rainbow/app/domain/service"
+)
+
+// CFnStackLister is a mock of the CFnStackLister interface.
+type CFnStackLister func(ctx context.Context, input *service.CFnStackListerInput) (*service.CFnStackListerOutput, error)
+
+// CFnStackLister calls the CFnStackListerFunc.
+func (m CFnStackLister) CFnStackLister(ctx context.Context, input *service.CFnStackListerInput) (*service.CFnStackListerOutput, error) {
+	return m(ctx, input)
+}

app/interactor/cloudformation_test.go

@@ -0,0 +1,84 @@
+package interactor
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/aws/aws-sdk-go-v2/aws"
+	"github.com/google/go-cmp/cmp"
+	"github.com/nao1215/rainbow/app/domain/model"
+	"github.com/nao1215/rainbow/app/domain/service"
+	"github.com/nao1215/rainbow/app/external/mock"
+	"github.com/nao1215/rainbow/app/usecase"
+)
+
+func TestCFnStackLister_ListCFnStack(t *testing.T) {
+	t.Parallel()
+
+	t.Run("success to get cloudformation stack list", func(t *testing.T) {
+		t.Parallel()
+
+		stackLister := mock.CFnStackLister(func(ctx context.Context, input *service.CFnStackListerInput) (*service.CFnStackListerOutput, error) {
+			want := &service.CFnStackListerInput{
+				Region: model.RegionAPEast1,
+			}
+			if diff := cmp.Diff(want, input); diff != "" {
+				t.Errorf("differs: (-want +got)\n%s", diff)
+			}
+
+			return &service.CFnStackListerOutput{
+				Stacks: []*model.Stack{
+					{
+						StackName: aws.String("stackName1"),
+						StackID:   aws.String(model.StackStatusCreateComplete.String()),
+					},
+					{
+						StackName: aws.String("stackName2"),
+						StackID:   aws.String(model.StackStatusCreateComplete.String()),
+					},
+				},
+			}, nil
+		})
+
+		lister := NewCFnStackLister(stackLister)
+		output, err := lister.ListCFnStack(context.Background(), &usecase.CFnStackListerInput{
+			Region: model.RegionAPEast1,
+		})
+		if err != nil {
+			t.Errorf("unexpected error: %v", err)
+		}
+
+		want := &usecase.CFnStackListerOutput{
+			Stacks: []*model.Stack{
+				{
+					StackName: aws.String("stackName1"),
+					StackID:   aws.String(model.StackStatusCreateComplete.String()),
+				},
+				{
+					StackName: aws.String("stackName2"),
+					StackID:   aws.String(model.StackStatusCreateComplete.String()),
+				},
+			},
+		}
+		if diff := cmp.Diff(want, output); diff != "" {
+			t.Errorf("differs: (-want +got)\n%s", diff)
+		}
+	})
+
+	t.Run("fail to get cloudformation stack list", func(t *testing.T) {
+		t.Parallel()
+
+		stackLister := mock.CFnStackLister(func(ctx context.Context, input *service.CFnStackListerInput) (*service.CFnStackListerOutput, error) {
+			return nil, errors.New("some error")
+		})
+
+		lister := NewCFnStackLister(stackLister)
+		_, err := lister.ListCFnStack(context.Background(), &usecase.CFnStackListerInput{
+			Region: model.RegionAPEast1,
+		})
+		if err == nil {
+			t.Error("expected error, but nil")
+		}
+	})
+}