Go: What are Go and end-to-end testing strategies?

1// Integration test with real DB
2func TestUserAPI(t *testing.T) {
3    if testing.Short() {
4        t.Skip("Skipping integration test")
5    }
6
7    // Setup
8    db := setupTestDB(t)
9    defer db.Close()
10
11    server := NewServer(db)
12    ts := httptest.NewServer(server)
13    defer ts.Close()
14
15    // Test creating a user
16    t.Run("create user", func(t *testing.T) {
17        payload := `{"name":"Alice","email":"alice@example.com"}`
18        resp, err := http.Post(
19            ts.URL+"/api/users",
20            "application/json",
21            strings.NewReader(payload),
22        )
23        if err != nil {
24            t.Fatal(err)
25        }
26        defer resp.Body.Close()
27
28        if resp.StatusCode != http.StatusCreated {
29            t.Errorf("expected 201, got %d", resp.StatusCode)
30        }
31
32        var user User
33        json.NewDecoder(resp.Body).Decode(&user)
34        if user.Name != "Alice" {
35            t.Errorf("expected Alice, got %s", user.Name)
36        }
37    })
38
39    // Test getting a user
40    t.Run("get user", func(t *testing.T) {
41        resp, err := http.Get(ts.URL + "/api/users/1")
42        if err != nil {
43            t.Fatal(err)
44        }
45        defer resp.Body.Close()
46
47        if resp.StatusCode != http.StatusOK {
48            t.Errorf("expected 200, got %d", resp.StatusCode)
49        }
50    })
51}
52
53// Test with containers (testcontainers)
54func TestWithContainer(t *testing.T) {
55    ctx := context.Background()
56
57    req := testcontainers.ContainerRequest{
58        Image:        "postgres:15",
59        ExposedPorts: []string{"5432/tcp"},
60        Env: map[string]string{
61            "POSTGRES_DB":       "testdb",
62            "POSTGRES_USER":     "test",
63            "POSTGRES_PASSWORD": "test",
64        },
65        WaitingFor: wait.ForListeningPort("5432/tcp"),
66    }
67
68    container, err := testcontainers.GenericContainer(ctx,
69        testcontainers.GenericContainerRequest{
70            ContainerRequest: req,
71            Started:          true,
72        },
73    )
74    if err != nil {
75        t.Fatal(err)
76    }
77    defer container.Terminate(ctx)
78
79    host, _ := container.Host(ctx)
80    port, _ := container.MappedPort(ctx, "5432")
81
82    dsn := fmt.Sprintf("postgres://test:test@%s:%s/testdb?sslmode=disable",
83        host, port.Port())
84
85    db, _ := sql.Open("postgres", dsn)
86    defer db.Close()
87
88    // Tests with real DB...
89}
90
91// BDD style with godog
92func FeatureContext(s *godog.Suite) {
93    s.Step(`^I have a user with name "([^"]*)"$`, iHaveAUserWithName)
94    s.Step(`^I should see the user$`, iShouldSeeTheUser)
95}
96
97func iHaveAUserWithName(name string) error {
98    _, err := db.CreateUser(&User{Name: name})
99    return err
100}
101
102func iShouldSeeTheUser() error {
103    user, err := db.GetUser(1)
104    if err != nil {
105        return err
106    }
107    if user == nil {
108        return errors.New("user not found")
109    }
110    return nil
111}