.NET Core之单元测试（三）：Mock框架Moq的使用

编写一个API

新增一个接口

public interface IFoo
{
bool Ping(string ip);
}


接口实现

public class Foo : IFoo
{
public bool Ping(string ip)
{
return new Random().Next(1, 100) % 2 == 1;
}
}


编写一个待测试的API，其中有三个依赖项：SqliteDbContext，ILogger<SampleController>和IFoo

API实现的功能：先获取SqliteDbContext中的SampleEntity，如果其中的属性StringValue值为ping，并且结果为False，则返回404，否则返回SampleEntity

[Route("api/[controller]")]
[ApiController]
public class SampleController : ControllerBase
{
private readonly SqliteDbContext _sqliteDbContext;
private readonly ILogger<SampleController> _logger;
private readonly IFoo _foo;
public SampleController(SqliteDbContext sqliteDbContext, ILogger<SampleController> logger,IFoo foo)
{
_logger = logger;
_foo = foo;
_sqliteDbContext = sqliteDbContext;
}
[HttpGet("{id}")]
public async Task<IActionResult> Get(int id)
{
var sampleData = await _sqliteDbContext.SampleEntity
.SingleOrDefaultAsync(s => s.Id == id);
if (sampleData?.StringValue == "ping")
{
var pingOk = _foo.Ping("localhost");
if (!pingOk)
return NotFound();
}
return Ok(sampleData);
}
}


测试用例

• Mock ILogger<SampleController>

var loggerMock = new Mock<ILogger<SampleController>>();
var logger = loggerMock.Object;


• Mock Ping(string ip)

var fooMock = new Mock<IFoo>();
fooMock.Setup(foo => foo.Ping("localhost")).Returns(true);
var foo = fooMock.Object;


关于Moq的更多操作可参见：Moq4 Quickstart

• 修改GetSqliteDbContextAsync()，新增一个ID为2的数据记录

private async Task<SqliteDbContext> GetSqliteDbContextAsync()
{
var options = new DbContextOptionsBuilder<SqliteDbContext>()
.UseInMemoryDatabase(Guid.NewGuid().ToString())
.Options;
var sqliteDbContext = new SqliteDbContext(options);
sqliteDbContext.SampleEntity.Add(new Infrastructure.Entities.SampleEntity
{
Id = 1,
BoolValue = false,
DateTimeValue = DateTime.Now,
StringValue = "sample"
}); sqliteDbContext.SampleEntity.Add(new Infrastructure.Entities.SampleEntity
{
Id = 2,
BoolValue = false,
DateTimeValue = DateTime.Now,
StringValue = "ping"
});
await sqliteDbContext.SaveChangesAsync();
return sqliteDbContext;
}


• 测试Ping==True

[TestMethod]
public async Task Get_ReturnOK_WithPingTrue()
{
// Arrange
var dbContext = await GetSqliteDbContextAsync(); var loggerMock = new Mock<ILogger<SampleController>>();
var logger = loggerMock.Object; var fooMock = new Mock<IFoo>();
fooMock.Setup(foo => foo.Ping("localhost")).Returns(true);
var foo = fooMock.Object; var controller = new SampleController(dbContext, logger, foo); // Act
var response = await controller.Get(2);
var responseModel = ((OkObjectResult)response).Value as SampleEntity; // Assert
Assert.IsInstanceOfType(response, typeof(OkObjectResult));
Assert.IsTrue(responseModel.Id == 2);
Assert.IsFalse(responseModel.BoolValue);
Assert.IsTrue(responseModel.StringValue == "ping");
}


• 测试Ping==False

[TestMethod]
public async Task Get_ReturnOK_WithPingFalse()
{
// Arrange
var dbContext = await GetSqliteDbContextAsync(); var loggerMock = new Mock<ILogger<SampleController>>();
var logger = loggerMock.Object; var fooMock = new Mock<IFoo>();
fooMock.Setup(foo => foo.Ping("localhost")).Returns(false);
var foo = fooMock.Object; var controller = new SampleController(dbContext, logger, foo); // Act
var response = await controller.Get(2); // Assert
Assert.IsInstanceOfType(response, typeof(NotFoundResult));
}


• 测试结果