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Kashif Soofi
Kashif Soofi

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Integration Test Postgres Store (Go)

This is a continuation of an earlier post REST API with Go, Chi, Postgres and sqlx. In this tutorial I will extend the sample to add integration tests to verify our implementation of postgres_movies_store.

Why Integration Test

As per definition from Wikipedia integration testing is the phase in which individual software modules are combined and tested as a group.

This is important in our case as we are using an external system to store our data and before we can declare that it is ready to use we need to make sure that it is working as intended.

Our options are

  • One way would be to run the database server and our api project and invoke the endpoints either from the Swagger UI, curl or Postman with defined data and then verify if our service is storing and retrieving the data correctly.This is tedious to do everytime we make a change, add or remove a property to our domain model, add a new endpoint for new use case.
  • Add set of integration tests to our source code and run everytime we make a change, this would ensure that any change we have made has not broken any existing funcationality and scenario. Important thing to remember is this is not set in stone and these should be updated as the funcationality evolves, new functionality would lead to adding new test cases.

Focus of this article would be to implement automated integration tests for PostgresMoviesStore we implemented earlier.

Test Setup

Let's start by adding a new folder integrationtests.

database_helper.go

I will start by adding database_helper.go, this will closely match postgres_movies_store.go but will provide its own methods for CRUD operations and it will keep track of the created records to clean up after the test finishes.

Here is the complete listing

package integrationtests

import (
    "context"

    "github.com/google/uuid"
    "github.com/jmoiron/sqlx"
    "github.com/kashifsoofi/blog-code-samples/integration-test-postgres-go/store"
    _ "github.com/lib/pq"
)

const driverName = "pgx"

type databaseHelper struct {
    databaseUrl string
    dbx         *sqlx.DB
    trackedIDs  map[uuid.UUID]any
}

func newDatabaseHelper(databaseUrl string) *databaseHelper {
    return &databaseHelper{
        databaseUrl: databaseUrl,
        trackedIDs:  map[uuid.UUID]any{},
    }
}

func (s *databaseHelper) connect(ctx context.Context) error {
    dbx, err := sqlx.ConnectContext(ctx, driverName, s.databaseUrl)
    if err != nil {
        return err
    }

    s.dbx = dbx
    return nil
}

func (s *databaseHelper) close() error {
    return s.dbx.Close()
}

func (s *databaseHelper) GetMovie(ctx context.Context, id uuid.UUID) (store.Movie, error) {
    err := s.connect(ctx)
    if err != nil {
        return store.Movie{}, err
    }
    defer s.close()

    var movie store.Movie
    if err := s.dbx.GetContext(
        ctx,
        &movie,
        `SELECT
            id, title, director, release_date, ticket_price, created_at, updated_at
        FROM movies
        WHERE id = $1`,
        id); err != nil {
        return store.Movie{}, err
    }

    return movie, nil
}

func (s *databaseHelper) AddMovie(ctx context.Context, movie store.Movie) error {
    err := s.connect(ctx)
    if err != nil {
        return err
    }
    defer s.close()

    if _, err := s.dbx.NamedExecContext(
        ctx,
        `INSERT INTO movies
            (id, title, director, release_date, ticket_price, created_at, updated_at)
        VALUES
            (:id, :title, :director, :release_date, :ticket_price, :created_at, :updated_at)`,
        movie); err != nil {
        return err
    }

    s.trackedIDs[movie.ID] = movie.ID
    return nil
}

func (s *databaseHelper) AddMovies(ctx context.Context, movies []store.Movie) error {
    for _, movie := range movies {
        if err := s.AddMovie(ctx, movie); err != nil {
            return err
        }
    }

    return nil
}

func (s *databaseHelper) DeleteMovie(ctx context.Context, id uuid.UUID) error {
    err := s.connect(ctx)
    if err != nil {
        return err
    }
    defer s.close()

    return s.deleteMovie(ctx, id)
}

func (s *databaseHelper) CleanupAllMovies(ctx context.Context) error {
    ids := []uuid.UUID{}
    for id := range s.trackedIDs {
        ids = append(ids, id)
    }
    return s.CleanupMovies(ctx, ids...)
}

func (s *databaseHelper) CleanupMovies(ctx context.Context, ids ...uuid.UUID) error {
    err := s.connect(ctx)
    if err != nil {
        return err
    }
    defer s.close()

    for _, id := range ids {
        if err := s.deleteMovie(ctx, id); err != nil {
            return err
        }
    }

    return nil
}

func (s *databaseHelper) deleteMovie(ctx context.Context, id uuid.UUID) error {
    _, err := s.dbx.ExecContext(ctx, `DELETE FROM movies WHERE id = $1`, id)
    if err != nil {
        return err
    }

    delete(s.trackedIDs, id)
    return nil
}
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postgres_movies_store_test.go

This file will contain the tests for each of the methods provided by PostgresMoviesStore. But first lets start by adding a TestMain metohd. We will load configuration from environment and initialize instances of databaseHelper, PostgresMoviesStore and faker.

We will also add 2 helper methods to generate test data using faker and a helper method to assert 2 instancs of store.Movie are equal, we will compare time fields to nearest second.

package integrationtests

import (
    "context"
    "math"
    "testing"
    "time"

    "github.com/google/uuid"
    "github.com/jaswdr/faker"

    "github.com/kashifsoofi/blog-code-samples/integration-test-postgres-go/config"
    "github.com/kashifsoofi/blog-code-samples/integration-test-postgres-go/store"
    "github.com/stretchr/testify/assert"
    "github.com/stretchr/testify/require"
)

var dbHelper *databaseHelper
var sut *store.PostgresMoviesStore

var fake faker.Faker

func TestMain(t *testing.T) {
    cfg, err := config.Load()
    require.Nil(t, err)

    dbHelper = newDatabaseHelper(cfg.DatabaseURL)

    sut = store.NewPostgresMoviesStore(cfg.DatabaseURL)

    fake = faker.New()
}

func createMovie() store.Movie {
    m := store.Movie{}
    fake.Struct().Fill(&m)
    m.TicketPrice = math.Round(m.TicketPrice*100) / 100
    m.CreatedAt = time.Now().UTC()
    m.UpdatedAt = time.Now().UTC()
    return m
}

func createMovies(n int) []store.Movie {
    movies := []store.Movie{}
    for i := 0; i < n; i++ {
        m := createMovie()
        movies = append(movies, m)
    }
    return movies
}

func assertMovieEqual(t *testing.T, expected store.Movie, actual store.Movie) {
    assert.Equal(t, expected.ID, actual.ID)
    assert.Equal(t, expected.Title, actual.Title)
    assert.Equal(t, expected.Director, actual.Director)
    assert.Equal(t, expected.ReleaseDate, actual.ReleaseDate)
    assert.Equal(t, expected.TicketPrice, actual.TicketPrice)
    assert.WithinDuration(t, expected.CreatedAt, actual.CreatedAt, 1*time.Second)
    assert.WithinDuration(t, expected.UpdatedAt, actual.UpdatedAt, 1*time.Second)
}
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Tests

I am going to group tests by the method and then use t.Run within test mehtod to run an individual scenario. We can also use table based tests to run individual scenarios. e.g. if there are 2 tests for GetAll, those would be in TestGetAll method and then I would run individual test with t.Run within that method.

Also before running tests, we would need to start the database server and apply migrations. Run following command to do that.

docker-compose -f docker-compose.dev-env.yml up -d
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GetAll Tests

For GetAll, we are going to implement 2 test. First test is simple that if there are no records added, GetAll should return an empty array. It would look like following

func TestGetAll(t *testing.T) {
    ctx := context.Background()

    t.Run("given no records, should return empty array", func(t *testing.T) {
        storeMovies, err := sut.GetAll(ctx)

        assert.Nil(t, err)
        assert.Empty(t, storeMovies)
        assert.Equal(t, len(storeMovies), 0)
    })
}
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For second test, we would start by creating test movies and then using the dbHelper to insert those records to the database before calling the GetAll method on PostgresMoviesStore. After getting the result we will verify if each record we added earlier using dbHelper is present in the GetAll method result of PostgresMoviesStore. We will also call a defer function to delete test data from the database.

func TestGetAll(t *testing.T) {
    ...
    t.Run("given records exist, should return array", func(t *testing.T) {
        movies := createMovies(3)
        err := dbHelper.AddMovies(ctx, movies)
        assert.Nil(t, err)

        defer func() {
            ids := []uuid.UUID{}
            for _, m := range movies {
                ids = append(ids, m.ID)
            }
            err := dbHelper.CleanupMovies(ctx, ids...)
            assert.Nil(t, err)
        }()

        storeMovies, err := sut.GetAll(ctx)

        assert.Nil(t, err)
        assert.NotEmpty(t, storeMovies)
        assert.GreaterOrEqual(t, len(storeMovies), len(movies))
        for _, m := range movies {
            for _, sm := range storeMovies {
                if m.ID == sm.ID {
                    assertMovieEqual(t, m, sm)
                    continue
                }
            }
        }
    })
}
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GetByID Tests

First test for GetByID is to try to get a record with a random id and verify that it return a RecordNotFoundError.

func TestGetByID(t *testing.T) {
    ctx := context.Background()

    t.Run("given record does not exist, should return error", func(t *testing.T) {
        id, err := uuid.Parse(fake.UUID().V4())
        assert.NoError(t, err)

        _, err = sut.GetByID(ctx, id)

        var targetErr *store.RecordNotFoundError
        assert.ErrorAs(t, err, &targetErr)
    })
}
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In our next test, we would first insert a record using dbHelper and then use our sut(system under test) to load the record and then finally verify that the inserted record is same as loaded record.

func TestGetByID(t *testing.T) {
    ...

    t.Run("given record exists, should return record", func(t *testing.T) {
        movie := createMovie()
        err := dbHelper.AddMovie(ctx, movie)
        assert.Nil(t, err)

        defer func() {
            err := dbHelper.DeleteMovie(ctx, movie.ID)
            assert.Nil(t, err)
        }()

        storeMovie, err := sut.GetByID(ctx, movie.ID)

        assert.Nil(t, err)
        assertMovieEqual(t, movie, storeMovie)
    })
}
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Create Tests

First test for Create is straight forward, we are going to generate some fake data for createMovieParam, create a new record using sut and then we would use our helper to load the record from database and assert the record was saved correctly.

func TestCreate(t *testing.T) {
    ctx := context.Background()

    t.Run("given record does not exist, should create record", func(t *testing.T) {
        p := store.CreateMovieParams{}
        fake.Struct().Fill(&p)
        p.TicketPrice = math.Round(p.TicketPrice*100) / 100
        p.ReleaseDate = fake.Time().Time(time.Now()).UTC()

        err := sut.Create(ctx, p)

        assert.Nil(t, err)
        defer func() {
            err := dbHelper.DeleteMovie(ctx, p.ID)
            assert.Nil(t, err)
        }()

        m, err := dbHelper.GetMovie(ctx, p.ID)
        assert.Nil(t, err)
        expected := store.Movie{
            ID:          p.ID,
            Title:       p.Title,
            Director:    p.Director,
            ReleaseDate: p.ReleaseDate,
            TicketPrice: p.TicketPrice,
            CreatedAt:   time.Now().UTC(),
            UpdatedAt:   time.Now().UTC(),
        }
        assertMovieEqual(t, expected, m)
    })
}
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2nd test is to check if the method returns an error if the id already exists. We will use dbHelper to add a new record first and then try to create a new record using PostgresMoviesStore.

func TestCreate(t *testing.T) {
    ...

    t.Run("given record with id exists, should return DuplicateKeyError", func(t *testing.T) {
        movie := createMovie()
        err := dbHelper.AddMovie(ctx, movie)
        assert.Nil(t, err)
        defer func() {
            err := dbHelper.DeleteMovie(ctx, movie.ID)
            assert.Nil(t, err)
        }()

        p := store.CreateMovieParams{
            ID:          movie.ID,
            Title:       movie.Title,
            Director:    movie.Director,
            ReleaseDate: movie.ReleaseDate,
            TicketPrice: movie.TicketPrice,
        }

        err = sut.Create(ctx, p)

        assert.NotNil(t, err)
        var targetErr *store.DuplicateKeyError
        assert.ErrorAs(t, err, &targetErr)
    })
}
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Update Tests

To test update, first we will create a record and then call the Update method of store to update the recrod. After updating the record we will use the dbHelper to load the saved record and assert the saved record has updated values.

func TestUpdate(t *testing.T) {
    ctx := context.Background()

    t.Run("given record exists, should update record", func(t *testing.T) {
        movie := createMovie()
        err := dbHelper.AddMovie(ctx, movie)
        assert.Nil(t, err)
        defer func() {
            err := dbHelper.DeleteMovie(ctx, movie.ID)
            assert.Nil(t, err)
        }()

        p := store.UpdateMovieParams{
            Title:       fake.RandomStringWithLength(20),
            Director:    fake.Person().Name(),
            ReleaseDate: fake.Time().Time(time.Now()).UTC(),
            TicketPrice: math.Round(fake.RandomFloat(2, 1, 100)*100) / 100,
        }

        err = sut.Update(ctx, movie.ID, p)

        assert.Nil(t, err)

        m, err := dbHelper.GetMovie(ctx, movie.ID)
        assert.Nil(t, err)
        expected := store.Movie{
            ID:          movie.ID,
            Title:       p.Title,
            Director:    p.Director,
            ReleaseDate: p.ReleaseDate,
            TicketPrice: p.TicketPrice,
            CreatedAt:   movie.CreatedAt,
            UpdatedAt:   time.Now().UTC(),
        }
        assertMovieEqual(t, expected, m)
    })
}
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Delete Tests

To test delete, first we will add a new record using dbHelper, then call Delete method on our sut. To verify the record was successfully deleted we would again use dbHelper to load the record and assert it returns error with string no rows in result set.

func TestDelete(t *testing.T) {
    ctx := context.Background()

    t.Run("given record exists, should delete record", func(t *testing.T) {
        movie := createMovie()
        err := dbHelper.AddMovie(ctx, movie)
        assert.Nil(t, err)
        defer func() {
            err := dbHelper.DeleteMovie(ctx, movie.ID)
            assert.Nil(t, err)
        }()

        err = sut.Delete(ctx, movie.ID)

        assert.Nil(t, err)

        _, err = dbHelper.GetMovie(ctx, movie.ID)
        assert.NotNil(t, err)
        assert.ErrorContains(t, err, "sql: no rows in result set")
    })
}
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Run Integration Tests

Run following go test command to run integration tests. Please remember pre-requisit of running these tests is to start database server and apply migrations.

DATABASE_URL=postgresql://postgres:Password123@localhost:5432/moviesdb?sslmode=disable go test ./integrationtests
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Integration Tests in CI

I am also adding 2 GitHub Actions workflows to run these integration tests as part of CI.

Setting up Postgres using GitHub Service Container

In this workflow we would make use of the GitHub service containers to start a Postgres server. We will build migrations container and run it as part of the build process to apply migrations before running integration tests. Here is the full listing.

name: Integration Test Postgres (Go)

on:
  push:
    branches: [ "main" ]
    paths:
     - 'integration-test-postgres-go/**'

jobs:
  build:
    runs-on: ubuntu-latest
    defaults:
      run:
        working-directory: integration-test-postgres-go

    services:
      postgres:
        image: postgres:14-alpine
        env:
          POSTGRES_USER: postgres
          POSTGRES_PASSWORD: Password123
          POSTGRES_DB: moviesdb
        options: >-
          --health-cmd pg_isready
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5
        ports:
          - 5432:5432

    steps:
      - uses: actions/checkout@v3
      - name: Set up Go
        uses: actions/setup-go@v4
        with:
          go-version: '1.20'
      - name: Build
        run: go build -v ./...
      - name: Build migratinos Docker image
        run: docker build --file ./db/Dockerfile -t movies.db.migrations ./db
      - name: Run migrations
        run: docker run --add-host=host.docker.internal:host-gateway movies.db.migrations "postgresql://postgres:Password123@host.docker.internal:5432/moviesdb?sslmode=disable" up
      - name: Run integration tests
        run: DATABASE_URL=postgresql://postgres:Password123@localhost:5432/moviesdb?sslmode=disable go test ./integrationtests
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Setting up Postgres using docker-compose

In this workflow we will use the docker-compose.dev-env.yml to start Postgres and apply migrations as a first step of the workflow after checking out the code. Here is the full listing.

name: Integration Test Postgres (Go) with docker-compose

on:
  push:
    branches: [ "main" ]
    paths:
     - 'integration-test-postgres-go/**'

jobs:
  build:
    runs-on: ubuntu-latest
    defaults:
      run:
        working-directory: integration-test-postgres-go

    steps:
      - uses: actions/checkout@v3
      - name: Start container and apply migrations
        run: docker compose -f "docker-compose.dev-env.yml" up -d --build
      - name: Set up Go
        uses: actions/setup-go@v4
        with:
          go-version: '1.20'
      - name: Build
        run: go build -v ./...
      - name: Run integration tests
        run: DATABASE_URL=postgresql://postgres:Password123@localhost:5432/moviesdb?sslmode=disable go test ./integrationtests
      - name: Stop containers
        run: docker compose -f "docker-compose.dev-env.yml" down --remove-orphans --rmi all --volumes
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Source

Source code for the demo application is hosted on GitHub in blog-code-samples repository.

Source for Integration Test Postgres (Go) workflow is in integration-test-postgres-go.yml.

Source for Integration Test Postgres (Go) with docker-compose workflow is in integration-test-postgres-go-docker-compose.yml.

References

In no particular order

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