feat: add test case for usecase user.create

internal/howmuch/usecase/repo/testuser.go

@@ -26,6 +26,7 @@ import (
 	"context"
 
 	"git.vinchent.xyz/vinchent/howmuch/internal/howmuch/model"
+	"github.com/pkg/errors"
 )
 
 type TestUserRepository struct{}
@@ -38,5 +39,10 @@ func (tur *TestUserRepository) Create(
 	user := *u
 
 	user.ID = 123
+
+	if user.Email == "duplicate@error.com" {
+		return nil, errors.New("blabla (SQLSTATE 23505)")
+	}
+
 	return &user, nil
 }

internal/howmuch/usecase/usecase/user_test.go

@@ -32,18 +32,34 @@ import (
 )
 
 func TestCreateUser(t *testing.T) {
-	ctx := context.Background()
-	userUsecase := NewUserUsecase(&repo.TestUserRepository{}, &repo.TestDBRepository{})
-	input := &model.User{
-		Email:     "a@b.c",
-		FirstName: "James",
-		LastName:  "Bond",
-		Password:  "verystrong",
-	}
-	want := input
-	want.ID = 123
+	t.Run("normal create", func(t *testing.T) {
+		ctx := context.Background()
+		userUsecase := NewUserUsecase(&repo.TestUserRepository{}, &repo.TestDBRepository{})
+		input := &model.User{
+			Email:     "a@b.c",
+			FirstName: "James",
+			LastName:  "Bond",
+			Password:  "verystrong",
+		}
+		want := input
+		want.ID = 123
 
-	got, err := userUsecase.Create(ctx, input)
-	assert.NoError(t, err)
-	assert.Equal(t, want, got)
+		got, err := userUsecase.Create(ctx, input)
+		assert.NoError(t, err)
+		assert.Equal(t, want, got)
+	})
+
+	t.Run("duplicate create", func(t *testing.T) {
+		ctx := context.Background()
+		userUsecase := NewUserUsecase(&repo.TestUserRepository{}, &repo.TestDBRepository{})
+		input := &model.User{
+			Email:     "duplicate@error.com",
+			FirstName: "James",
+			LastName:  "Bond",
+			Password:  "verystrong",
+		}
+
+		_, err := userUsecase.Create(ctx, input)
+		assert.EqualError(t, err, UserExisted.Error())
+	})
 }