单元测试涉及数据库交互的 go 函数时，可以通过以下步骤进行：设置测试数据库，如 sqlite；创建测试函数，如 getuser；编写单元测试，验证 getuser 函数的输出，覆盖不同的测试用例。

如何对涉及数据库交互的 Golang 函数进行单元测试

在编写涉及数据库交互的 Golang 函数时，进行单元测试至关重要。以下是使用 database/sql 包进行单元测试的步骤：

1. 设置测试数据库

立即学习“go语言免费学习笔记（深入）”；

对于此示例，我们将使用 [SQLite](https://www.sqlite.org/) 作为测试数据库。

import (
    "database/sql"
    "log"
    "os"
    "testing"

    "github.com/mattn/go-sqlite3"
)

var (
    testDB *sql.DB
)

func setupTestDB(t *testing.T) {
    dbPath := ":memory:"
    conn, err := sqlite3.Open(dbPath)
    if err != nil {
        t.Fatalf("Could not open test database: %v", err)
    }
    testDB, err = sql.Open("sqlite3", conn)
    if err != nil {
        t.Fatalf("Could not connect to test database: %v", err)
    }
}

2. 创建测试函数

我们将创建要测试的函数：

func GetUser(id int) (*User, error) {
    row := testDB.QueryRow(
        "SELECT * FROM users WHERE id = ?", id,
    )

    var user User
    err := row.Scan(&user.ID, &user.Name, &user.Email)
    if err != nil {
        return nil, err
    }

    return &user, nil
}

3. 编写单元测试

现在，让我们编写一个测试函数来验证 GetUser 函数：

func TestGetUser(t *testing.T) {
    setupTestDB(t)
    defer testDB.Close()

    // 编写测试用例
    type testCase struct {
        id    int
        input int
        want  *User
        err   bool
    }

    testCases := []testCase{
        {id: 1, input: 1, want: &User{ID: 1, Name: "John Doe", Email: "john@example.com"}, err: false},
        {id: 2, input: 2, want: nil, err: true},
    }

    for _, tc := range testCases {
        user, err := GetUser(tc.input)

        if (tc.err && err == nil) || (!tc.err && err != nil) {
            t.Errorf("Expected error=%t, got %v", tc.err, err)
        }

        if tc.err {
            continue
        }

        if tc.want.ID != user.ID || tc.want.Name != user.Name || tc.want.Email != user.Email {
            t.Errorf("Expected result: %v, got: %v", tc.want, user)
        }
    }
}

实战案例

以下是一份使用 database/sql 包执行单元测试的完整示例：

// test_user.go

package main

import (
    "database/sql"
    "log"
    "os"
    "testing"
    "time"

    _ "github.com/mattn/go-sqlite3"
)

type User struct {
    ID       int
    Name     string
    Email    string
    Birthday time.Time
}

func setupTestDB(t *testing.T) {
    dbPath := ":memory:"
    conn, err := sqlite3.Open(dbPath)
    if err != nil {
        t.Fatalf("Could not open test database: %v", err)
    }
    testDB, err = sql.Open("sqlite3", conn)
    if err != nil {
        t.Fatalf("Could not connect to test database: %v", err)
    }

    _, err = testDB.Exec(
        `CREATE TABLE users (
            id INTEGER PRIMARY KEY,
            name TEXT NOT NULL,
            email TEXT UNIQUE,
            birthday DATETIME
        )`,
    )
    if err != nil {
        t.Fatalf("Could not create test table: %v", err)
    }
}

func TestInsertUser(t *testing.T) {
    setupTestDB(t)
    defer testDB.Close()

    type testCase struct {
        input *User
        want  *User
        err   bool
    }

    testCases := []testCase{
        {
            input: &User{Name: "John Doe", Email: "john@example.com", Birthday: time.Date(1980, time.January, 1, 0, 0, 0, 0, time.UTC)},
            want: &User{ID: 1, Name: "John Doe", Email: "john@example.com", Birthday: time.Date(1980, time.January, 1, 0, 0, 0, 0, time.UTC)},
            err:  false,
        },
        {
            input: &User{Name: "Jane Doe", Email: "jane@example.com", Birthday: time.Date(1990, time.March, 8, 0, 0, 0, 0, time.UTC)},
            want: &User{ID: 2, Name: "Jane Doe", Email: "jane@example.com", Birthday: time.Date(1990, time.March, 8, 0, 0, 0, 0, time.UTC)},
            err:  false,
        },
        {
            input: &User{Name: "Invalid Name", Email: "invalid@email.com", Birthday: time.Date(2000, time.April, 1, 0, 0, 0, 0, time.UTC)},
            want:  nil,
            err:   true,
        },
    }

    for _, tc := range testCases {
        user, err := InsertUser(tc.input)

        if (tc.err && err == nil) || (!tc.err && err != nil) {
            t.Errorf("Expected error=%t, got %v", tc.err, err)
        }

        if tc.err {
            continue
        }

        if tc.want.ID != user.ID || tc.want.Name != user.Name || tc.want.Email != user.Email || tc.want.Birthday != user.Birthday {