Implements /transactions POST method

It adds the method to the OpenAPI spec and generates a new server
config. The requirement for the ID on the Transaction component is
removed, so that it can be reused for insertions.
It also adds two new middlewares, a logging and a spec validator. If a
request does not follow the spec, a 400 is returned immediately.

Issue: #18

cmd/api-server/main.go

@@ -12,6 +12,8 @@ import (
 	_ "github.com/jackc/pgx/v5/stdlib"
 	"github.com/joho/godotenv"
 	"github.com/labstack/echo/v4"
+	"github.com/labstack/echo/v4/middleware"
+	echomiddleware "github.com/oapi-codegen/echo-middleware"
 )
 
 func main() {
@@ -41,6 +43,14 @@ func main() {
 
 	// 3. HTTP server
 	e := echo.New()
+	e.Use(middleware.Logger())
+
+	swagger, err := api.GetSwagger()
+	if err != nil {
+		log.Fatalf("unable to get API swagger: %v\n", err)
+	}
+	e.Use(echomiddleware.OapiRequestValidator(swagger))
+
 	handlers := api.ServerImpl{Dal: &dal}
 	api.RegisterHandlers(e, &handlers)
 

docs/openapi.yaml

@@ -56,6 +56,23 @@ paths:
                 $ref: "#/components/schemas/Transactions"
         "204":
           description: No transactions
+    post:
+      summary: Create a new transaction
+      operationId: createTransaction
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/Transaction"
+      responses:
+        "201":
+          description: Transaction created
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Transaction"
+        "400":
+          description: Transaction not created
 
   /transaction/{transactionId}:
     get:
@@ -138,7 +155,6 @@ components:
         category:
           type: string
       required:
-        - id
         - date
         - description
         - value

go.mod

@@ -7,6 +7,9 @@ require (
 	github.com/deepmap/oapi-codegen/v2 v2.1.0
 	github.com/google/uuid v1.6.0
 	github.com/jackc/pgx/v5 v5.5.5
+	github.com/joho/godotenv v1.5.1
+	github.com/labstack/echo/v4 v4.12.0
+	github.com/oapi-codegen/echo-middleware v1.0.1
 	github.com/oapi-codegen/runtime v1.1.1
 	github.com/shopspring/decimal v1.4.0
 	github.com/stretchr/testify v1.9.0
@@ -19,13 +22,13 @@ require (
 	github.com/getkin/kin-openapi v0.124.0
 	github.com/go-openapi/jsonpointer v0.21.0 // indirect
 	github.com/go-openapi/swag v0.23.0 // indirect
+	github.com/golang-jwt/jwt v3.2.2+incompatible // indirect
+	github.com/gorilla/mux v1.8.1 // indirect
 	github.com/invopop/yaml v0.3.1 // indirect
 	github.com/jackc/pgpassfile v1.0.0 // indirect
 	github.com/jackc/pgservicefile v0.0.0-20231201235250-de7065d80cb9 // indirect
 	github.com/jackc/puddle/v2 v2.2.1 // indirect
-	github.com/joho/godotenv v1.5.1
 	github.com/josharian/intern v1.0.0 // indirect
-	github.com/labstack/echo/v4 v4.12.0
 	github.com/labstack/gommon v0.4.2 // indirect
 	github.com/mailru/easyjson v0.7.7 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
@@ -41,6 +44,7 @@ require (
 	golang.org/x/sync v0.7.0 // indirect
 	golang.org/x/sys v0.20.0 // indirect
 	golang.org/x/text v0.15.0 // indirect
+	golang.org/x/time v0.5.0 // indirect
 	golang.org/x/tools v0.21.0 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

go.sum

@@ -17,8 +17,12 @@ github.com/go-openapi/swag v0.23.0 h1:vsEVJDUo2hPJ2tu0/Xc+4noaxyEffXNIs3cOULZ+Gr
 github.com/go-openapi/swag v0.23.0/go.mod h1:esZ8ITTYEsH1V2trKHjAN8Ai7xHb8RV+YSZ577vPjgQ=
 github.com/go-test/deep v1.0.8 h1:TDsG77qcSprGbC6vTN8OuXp5g+J+b5Pcguhf7Zt61VM=
 github.com/go-test/deep v1.0.8/go.mod h1:5C2ZWiW0ErCdrYzpqxLbTX7MG14M9iiw8DgHncVwcsE=
+github.com/golang-jwt/jwt v3.2.2+incompatible h1:IfV12K8xAKAnZqdXVzCZ+TOjboZ2keLg81eXfW3O+oY=
+github.com/golang-jwt/jwt v3.2.2+incompatible/go.mod h1:8pz2t5EyA70fFQQSrl6XZXzqecmYZeUEB8OUGHkxJ+I=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/gorilla/mux v1.8.1 h1:TuBL49tXwgrFYWhqrNgrUNEY92u81SPhu7sTdzQEiWY=
+github.com/gorilla/mux v1.8.1/go.mod h1:AKf9I4AEqPTmMytcMc0KkNouC66V3BtZ4qD5fmWSiMQ=
 github.com/invopop/yaml v0.3.1 h1:f0+ZpmhfBSS4MhG+4HYseMdJhoeeopbSKbq5Rpeelso=
 github.com/invopop/yaml v0.3.1/go.mod h1:PMOp3nn4/12yEZUFfmOuNHJsZToEEOwoWsT+D81KkeA=
 github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsIM=
@@ -52,6 +56,8 @@ github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWE
 github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/mohae/deepcopy v0.0.0-20170929034955-c48cc78d4826 h1:RWengNIwukTxcDr9M+97sNutRR1RKhG96O6jWumTTnw=
 github.com/mohae/deepcopy v0.0.0-20170929034955-c48cc78d4826/go.mod h1:TaXosZuwdSHYgviHp1DAtfrULt5eUgsSMsZf+YrPgl8=
+github.com/oapi-codegen/echo-middleware v1.0.1 h1:edYGScq1phCcuDoz9AqA9eHX+tEI1LNL5PL1lkkQh1k=
+github.com/oapi-codegen/echo-middleware v1.0.1/go.mod h1:DBQKRn+D/vfXOFbaX5GRwFttoJY64JH6yu+pdt7wU3o=
 github.com/oapi-codegen/runtime v1.1.1 h1:EXLHh0DXIJnWhdRPN2w4MXAzFyE4CskzhNLUmtpMYro=
 github.com/oapi-codegen/runtime v1.1.1/go.mod h1:SK9X900oXmPWilYR5/WKPzt3Kqxn/uS/+lbpREv+eCg=
 github.com/perimeterx/marshmallow v1.1.5 h1:a2LALqQ1BlHM8PZblsDdidgv1mWi1DgC2UmX50IvK2s=
@@ -92,6 +98,8 @@ golang.org/x/sys v0.20.0 h1:Od9JTbYCk261bKm4M/mw7AklTlFYIa0bIp9BgSm1S8Y=
 golang.org/x/sys v0.20.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.15.0 h1:h1V/4gjBv8v9cjcR6+AR5+/cIYK5N/WAgiv4xlsEtAk=
 golang.org/x/text v0.15.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
+golang.org/x/time v0.5.0 h1:o7cqy6amK/52YcAKIPlM3a+Fpj35zvRj2TP+e1xFSfk=
+golang.org/x/time v0.5.0/go.mod h1:3BpzKBy/shNhVucY/MWOyx10tF3SFh9QdLuxbVysPQM=
 golang.org/x/tools v0.21.0 h1:qc0xYgIbsSDt9EyWz05J5wfa7LOVW0YTLOXrqdLAWIw=
 golang.org/x/tools v0.21.0/go.mod h1:aiJjzUbINMkxbQROHiO6hDPo2LHcIPhhQsa9DLh0yGk=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

internal/api/converter.go

@@ -3,17 +3,41 @@ package api
 import (
 	"git.rosemyrtle.work/personal-finance/server/internal/entity"
 	openapi_types "github.com/oapi-codegen/runtime/types"
+	"github.com/shopspring/decimal"
 )
 
-func convertTransaction(t entity.Transaction) Transaction {
+func ptr[T any](v T) *T {
+	return &v
+}
+
+func entity2transaction(t entity.Transaction) Transaction {
 	return Transaction{
-		nil, openapi_types.Date{Time: t.Date}, t.Description, int64(t.Id), float32(t.Value.InexactFloat64())}
+		nil,
+		openapi_types.Date{Time: t.Date},
+		t.Description,
+		ptr(int64(t.Id)),
+		float32(t.Value.InexactFloat64()),
+	}
+}
+
+func transaction2entity(t Transaction) entity.Transaction {
+	var id uint64 = entity.InvalidId
+	if t.Id != nil {
+		id = uint64(*t.Id)
+	}
+
+	return entity.Transaction{
+		Id:          id,
+		Date:        t.Date.Time,
+		Description: t.Description,
+		Value:       decimal.NewFromFloat32(t.Value),
+	}
 }
 
 func convertTransactions(ts entity.Transactions) Transactions {
 	var ans Transactions
 	for _, t := range ts {
-		ans = append(ans, convertTransaction(t))
+		ans = append(ans, entity2transaction(t))
 	}
 	return ans
 }

internal/api/impl.go

@@ -73,5 +73,21 @@ func (server *ServerImpl) GetTransactionById(ctx echo.Context, transactionId int
 		return ctx.NoContent(http.StatusNotFound)
 	}
 
-	return ctx.JSON(http.StatusOK, convertTransaction(*transaction))
+	return ctx.JSON(http.StatusOK, entity2transaction(*transaction))
+}
+
+func (server *ServerImpl) CreateTransaction(ctx echo.Context) error {
+	t := new(Transaction)
+	if err := ctx.Bind(t); err != nil {
+		log.Printf("%v", err)
+		return ctx.NoContent(http.StatusBadRequest)
+	}
+
+	ans, err := server.Dal.InsertTransaction(transaction2entity(*t))
+	if err != nil {
+		log.Printf("%v", err)
+		return ctx.NoContent(http.StatusInternalServerError)
+	}
+
+	return ctx.JSON(http.StatusCreated, entity2transaction(ans))
 }

internal/api/impl_test.go

@@ -3,7 +3,9 @@ package api
 import (
 	"net/http"
 	"net/http/httptest"
+	"reflect"
 	"strconv"
+	"strings"
 	"testing"
 	"time"
 
@@ -224,3 +226,63 @@ func TestServerImpl_GetTransactionById(t *testing.T) {
 		})
 	}
 }
+
+func TestServerImpl_CreateTransaction(t *testing.T) {
+	ctrl := gomock.NewController(t)
+	defer ctrl.Finish()
+	mock_dal := mock.NewMockDAL(ctrl)
+
+	date, _ := time.Parse(time.DateOnly, "1974-04-25")
+
+	type fields struct {
+		Dal dal.DAL
+	}
+	type args struct {
+		request string
+	}
+	type want struct {
+		entity   entity.Transaction
+		response string
+	}
+	tests := []struct {
+		name    string
+		fields  fields
+		args    args
+		want    want
+		wantErr bool
+	}{
+		{
+			"201",
+			fields{mock_dal},
+			args{`{"date": "1974-04-25", "description": "freedom", "value": 9000}`},
+			want{
+				entity.Transaction{Id: 1, Date: date, Description: "freedom", Value: decimal.New(9000, 0)},
+				`{"date":"1974-04-25","description":"freedom","id":1,"value":9000}`,
+			},
+			false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			s := &ServerImpl{Dal: tt.fields.Dal}
+
+			req := httptest.NewRequest(http.MethodPost, "/transactions", strings.NewReader(tt.args.request))
+			req.Header.Set(echo.HeaderContentType, echo.MIMEApplicationJSON)
+			rec := httptest.NewRecorder()
+			e := echo.New()
+			ctx := e.NewContext(req, rec)
+
+			inserted := tt.want.entity
+			inserted.Id = entity.InvalidId
+			mock_dal.EXPECT().InsertTransaction(gomock.AssignableToTypeOf(reflect.TypeOf(tt.want.entity))).Return(tt.want.entity, nil).Times(1)
+
+			if err := s.CreateTransaction(ctx); (err != nil) != tt.wantErr {
+				t.Errorf("ServerImpl.GetTransactionById() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(strings.TrimSpace(rec.Body.String()), tt.want.response) {
+				t.Errorf("DalImpl.InsertTransaction() = %v, want %v", rec.Body.String(), tt.want.response)
+			}
+		})
+	}
+}

internal/api/server.gen.go

@@ -34,7 +34,7 @@ type Transaction struct {
 	Category    *string            `json:"category,omitempty"`
 	Date        openapi_types.Date `json:"date"`
 	Description string             `json:"description"`
-	Id          int64              `json:"id"`
+	Id          *int64             `json:"id,omitempty"`
 	Value       float32            `json:"value"`
 }
 
@@ -59,6 +59,9 @@ type GetTransactionsParams struct {
 	Sort *string `form:"sort,omitempty" json:"sort,omitempty"`
 }
 
+// CreateTransactionJSONRequestBody defines body for CreateTransaction for application/json ContentType.
+type CreateTransactionJSONRequestBody = Transaction
+
 // ServerInterface represents all server handlers.
 type ServerInterface interface {
 	// Find bank by ID
@@ -73,6 +76,9 @@ type ServerInterface interface {
 	// Retrieve existing transactions
 	// (GET /transactions)
 	GetTransactions(ctx echo.Context, params GetTransactionsParams) error
+	// Create a new transaction
+	// (POST /transactions)
+	CreateTransaction(ctx echo.Context) error
 }
 
 // ServerInterfaceWrapper converts echo contexts to parameters.
@@ -167,6 +173,15 @@ func (w *ServerInterfaceWrapper) GetTransactions(ctx echo.Context) error {
 	return err
 }
 
+// CreateTransaction converts echo context to params.
+func (w *ServerInterfaceWrapper) CreateTransaction(ctx echo.Context) error {
+	var err error
+
+	// Invoke the callback with all the unmarshaled arguments
+	err = w.Handler.CreateTransaction(ctx)
+	return err
+}
+
 // This is a simple interface which specifies echo.Route addition functions which
 // are present on both echo.Echo and echo.Group, since we want to allow using
 // either of them for path registration
@@ -199,27 +214,29 @@ func RegisterHandlersWithBaseURL(router EchoRouter, si ServerInterface, baseURL
 	router.GET(baseURL+"/banks", wrapper.GetBanks)
 	router.GET(baseURL+"/transaction/:transactionId", wrapper.GetTransactionById)
 	router.GET(baseURL+"/transactions", wrapper.GetTransactions)
+	router.POST(baseURL+"/transactions", wrapper.CreateTransaction)
 
 }
 
 // Base64 encoded, gzipped, json marshaled Swagger object
 var swaggerSpec = []string{
 
-	"H4sIAAAAAAAC/8RWTW/jNhP+KwTf96hIShz0oFO7CDYwUGyDbnva7oGWRjJ3+aElh3YNw/+9GEqx9ZU4",
+	"H4sIAAAAAAAC/8RWTW/jNhD9KwTboyIpcdCDTm0abGCg2Abd9rTdAy2NbO5SpJYc2jUM//diKMWmPhKn",
-	"BbrtxZE0w5lnnnlmmCMvrW6tAYOeF0fuyy1oER/fCfOV/rbOtuBQQvwqK/rFQwu84B6dNA0/JdwIDcsG",
+	"QLN7cSRxOPPmzeNjDrw0TWs0aHS8OHBXbqAR4fFO6C/0t7WmBYsSwldZ0S/uW+AFd2ilXvNjwrVoYH7B",
-	"6yrZgFnHc7V1WiAveAiy4snU/ZRwB9+CdFDx4hOPLjHy57Or3XyBEiky4esgIej48H8HNS/4/7JLTVlf",
+	"2EquQS/DvtrYRiAvuPey4sk4/JhwC1+9tFDx4iMPISHzp1OoWX2GEikz4esgITTh4UcLNS/4D9m5p6xv",
-	"UBarOZ3DCOfEgd5/c8J4UaK0Zl5sKRAa6w6LlVUCYVRT/JAsOIIvnWyfU8zsckyNNPjDPU+4lkbqoHmR",
+	"KAvdHE9phLViT+9/WqGdKFEaPW22FAhrY/eznVUCYdBT+JDMBIIrrWyfSkzW5ZAaqfGnW57wRmrZ+IYX",
-	"n2NKg9CAo0M7ocI4fa2swEt+E/SGXJc47ZEOgT1HXGJ6wNHbCR8SO+OdUElT20iyNShKpEfQQioqRRph",
+	"+Smn1AhrsLRpK5Qflq+VEXiur32zotARpz3IGNNTsjmSI3pez3XM6YRyAiR1bQK/RqMokR6hEVJRF1IL",
-	"SvhRB4cirWA3o5E/gfPWCMXed77sI7gduD+oEiVLMD6y0+mSP374nT2CAScUewobJUv2c+fEdqs0Z9Yx",
+	"XcLPjbco0gq2Ewb5I1hntFDsXRfLPoDdgv2bOlGyBO0CMZ0k+cP7v9gDaLBCsUe/UrJkv3VBbLtIc2Ys",
-	"JRAcT3hwhGCL2Poiy/b7fdqYkFrXZH1YnzWtulml+Y1HYSqhrIF0i1rFMiUqWIJ3w35pwfz0tGarNCe2",
+	"UwLB8oR7Swg2iK0rsmy326Vr7VNj11mf1mXrVl0t0vzKodCVUEZDusFGhTYlKpiDd8V+b0H/8rhkizQn",
-	"wfmukjzN01s6a1swopW84Ks0T1c84a3AbSQ62wjzNTvS77o60ZcGImOkVkGU0HzxR0DS+bvDuoqnndCA",
+	"tsG6rpM8zdNr2mta0KKVvOCLNE8XPOGtwE0gOlsJ/SU70O+yOtKXNQTGSKiCKKGjxR8ASeJ3+2UVdlvR",
-	"4DwvPh0n/K0fmK0ZBWRomQMMjqiTZKO0z5NX8C4pH8oIXYCk3xULkj59JmffWmKL7Hd5/txpMBG3aFsl",
+	"AIJ1vPh4GPG3vGemZpSQoWEW0FuiTtIalX06dAXvivJYQWg9JL1NzKj5+ImCXWuILVq/yfOnSYMOuEXb",
-	"y4g8++K7wbjEuz7Ip5kgPoayBO/roNiZFGL1vss9qd7shJIVWz8wHwgKVJ3v/dyXEjJjkdU2mCoOlA9a",
+	"KlkG5Nln152Jc77LZ/g4EcQHX5bgXO0VO5FCrN52tUfd661QsmLLe+Y8QYGqi72dxlJBpg2y2nhdhbPk",
-	"C1oL/L00Vcfi5sDWD9Eam+WvNcnz70yS/zss3S1V/sGyTR9oWPOvgE7CDhj8KT1K0wy8MryMfXYcvFyR",
+	"fNMIcgT+TuqqY3G1Z8v7sBqG5S4NyfE3Jsn9F5Zu5jp/b9iqTxT3/AeglbAFBv9Ih1Kvo6gMz8c+O0Qv",
-	"7WBbvF29g/DXRDxC8qqWZ3t4unu/q7pHW/NfFPkg7+taH3I+kDxOrog39Nlfa3ItFYKjLMOk5zu57/O3",
+	"F2QbucXr1RulvyTiAZIXtTyx4LHtvqm6B675DUUe1X1Z6zHnkeRxdEW8Ys7u0pBrqRAsVYmLnq7jfs5f",
-	"APGlb/TAfGHcBKXEhhZz1+3Zvx3T1N3lOdGYn4tsklxJLXGUuYJaBIW8uM3zZKSt1d2VO36Oyta1B2S1",
+	"PYSXftDR8plx7ZUSKzLmbtqT/zjGpbt7c6QxNxXZqLiSjcRB5Qpq4RXy4jrPk4G2FjcXrvcpKlPXDpDV",
-	"s5rtt+CgB9RNI46pXcLXBVgGeHO7gO86pn4StxCXwAt5e9PLF0Yy7z2oitFx6v9+K8stFeutwxdy9Kb/",
+	"1jRstwELPaDuNOKQ2jl8XYJ5gFfXM/guY+pP4gaCCTxTt196/sJIprMHVTHaTvPfbWS5oWadsfhMjX7p",
-	"5lIayfofWLs4jvf69p04n05/BQAA///FWDm91QsAAA==",
+	"+1xKA1n/D7aLw3wvu+8wOOGtcTOH71cLAiH2l84FweGdqfZv5WDHCevX38osY08rQ/fVs1459r9T/ID7",
+	"jkMmmIZdTHto9N8AAAD//+YRCdlGDQAA",
 }
 
 // GetSwagger returns the content of the embedded swagger specification file

internal/dal/dal.go

@@ -5,6 +5,7 @@ import "git.rosemyrtle.work/personal-finance/server/internal/entity"
 type DAL interface {
 	Transaction(transactionId int64) (*entity.Transaction, error)
 	Transactions() (entity.Transactions, error)
+	InsertTransaction(entity.Transaction) (entity.Transaction, error)
 	Bank(bankId string) (*entity.Bank, error)
 	Banks() (entity.Banks, error)
 }

internal/dal/impl.go

@@ -46,6 +46,28 @@ func (dal *DalImpl) Transactions() (entity.Transactions, error) {
 	return convert[entity.Transaction](rows), nil
 }
 
+func (dal *DalImpl) InsertTransaction(t entity.Transaction) (entity.Transaction, error) {
+	log.Print("DAL::InsertTransaction")
+
+	if dal.Db == nil {
+		log.Panic("database not available")
+	}
+
+	stmt := `
+	INSERT INTO pfbudget.transactions (date, description, value)
+	VALUES ($1, $2, $3)
+	RETURNING id
+	`
+
+	id := new(uint64)
+	if err := dal.Db.QueryRow(stmt, t.Date, t.Description, t.Value).Scan(id); err != nil {
+		return entity.Transaction{}, err
+	}
+
+	t.Id = *id
+	return t, nil
+}
+
 func (dal *DalImpl) Bank(bankId string) (*entity.Bank, error) {
 	log.Printf("DAL::Bank(%v)", bankId)
 

internal/dal/impl_test.go

@@ -260,3 +260,60 @@ func TestDalImpl_Banks(t *testing.T) {
 		})
 	}
 }
+
+func TestDalImpl_InsertTransaction(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatal(err)
+	}
+	date := time.Now()
+
+	type fields struct {
+		Db *sql.DB
+	}
+	type args struct {
+		t entity.Transaction
+	}
+	tests := []struct {
+		name    string
+		fields  fields
+		args    args
+		want    entity.Transaction
+		wantErr bool
+	}{
+		{
+			"201",
+			fields{db},
+			args{entity.Transaction{Id: entity.InvalidId, Date: date, Description: "freedom", Value: decimal.NewFromInt(9000)}},
+			entity.Transaction{Id: 1, Date: date, Description: "freedom", Value: decimal.NewFromInt(9000)},
+			false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			dal := &DalImpl{
+				Db: tt.fields.Db,
+			}
+
+			mock.
+				ExpectQuery(`
+					INSERT INTO .* \(date, description, value\)
+					VALUES \(\$1, \$2, \$3\)
+					RETURNING id`).
+				WithArgs(tt.args.t.Date, tt.args.t.Description, tt.args.t.Value).
+				WillReturnRows(
+					mock.NewRows([]string{"id"}).
+						AddRows([]driver.Value{tt.want.Id}),
+				)
+
+			got, err := dal.InsertTransaction(tt.args.t)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("DalImpl.InsertTransaction() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("DalImpl.InsertTransaction() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

internal/entity/entity.go

@@ -7,6 +7,8 @@ import (
 	"github.com/shopspring/decimal"
 )
 
+const InvalidId uint64 = 0
+
 type Transaction struct {
 	Id          uint64
 	Date        time.Time

internal/mock/mock_dal.gen.go

@@ -69,6 +69,21 @@ func (mr *MockDALMockRecorder) Banks() *gomock.Call {
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Banks", reflect.TypeOf((*MockDAL)(nil).Banks))
 }
 
+// InsertTransaction mocks base method.
+func (m *MockDAL) InsertTransaction(arg0 entity.Transaction) (entity.Transaction, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "InsertTransaction", arg0)
+	ret0, _ := ret[0].(entity.Transaction)
+	ret1, _ := ret[1].(error)
+	return ret0, ret1
+}
+
+// InsertTransaction indicates an expected call of InsertTransaction.
+func (mr *MockDALMockRecorder) InsertTransaction(arg0 any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "InsertTransaction", reflect.TypeOf((*MockDAL)(nil).InsertTransaction), arg0)
+}
+
 // Transaction mocks base method.
 func (m *MockDAL) Transaction(arg0 int64) (*entity.Transaction, error) {
 	m.ctrl.T.Helper()