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mock中的mock嵌套属性

mockk junit android

0

Mahdi-Malv · 技术社区 · 5 年前

我有一个函数,它在 DisplayMetrics 属于 Resources 属于 Context 班级:

fun getIconForDevice(context: Context, iconUrl: String): String {
    val metrics = context.resources.displayMetrics
    var suffix = ""
    //below checks MUST be in this increasing order or it may failed
    if (metrics.densityDpi <= DisplayMetrics.DENSITY_MEDIUM)
        suffix = "-m"
    else if (metrics.densityDpi <= DisplayMetrics.DENSITY_HIGH)
        suffix = "-h"
    else if (metrics.densityDpi <= DisplayMetrics.DENSITY_XHIGH)
        suffix = "-xh"
    else if (metrics.densityDpi <= DisplayMetrics.DENSITY_XXHIGH || metrics.densityDpi > DisplayMetrics.DENSITY_XXHIGH)
        suffix = "-xxh"
    val pasvand = iconUrl.substring(iconUrl.lastIndexOf("."))
    val str = iconUrl.substring(0, iconUrl.lastIndexOf(".")) + suffix + pasvand
    return str
}

上下文 和 metrics.densityDpi
我在用 模拟(1.9.3) 去图书馆。

@Test
fun getIconForDevice_ReturnsUrlWithXxhForXxhDisplay() {
    val context: Context = mockk(relaxed = true)
    every { context.resources.displayMetrics.densityDpi } returns 450
    assertEquals(IconHelper.getIconForDevice(context,
      "https://website.com/image.png"), "https://website.com/image-xxh.png")
}

运行测试时出现以下错误:

java.lang.ClassCastException: java.lang.Integer cannot be cast to android.util.DisplayMetrics

    at ...Resources.getDisplayMetrics(Resources.java)
    at ....IconHelper.getIconForDevice(IconHelper.kt:39)
    at ...IconHelperTest.getIconForDevice_ReturnsUrlWithXxhForXxhDisplay(IconHelperTest.kt:30)

val metrics = context.resources.displayMetrics 实际函数的行

那么,如何在mockk中模拟这样一个嵌套字段呢?
context.resources.displayMetrics.densityDpi

0 回复 | 直到 5 年前

1

ChristianB 5 年前

你的嘲笑计划 Context 和 densityDpi 是正确的。

测试失败,因为您正在呼叫 getIconForDevice 用一个新的mock代替你的mock 上下文 .

@Test
fun getIconForDevice_ReturnsUrlWithXxhForXxhDisplay() {
    val context: Context = mockk(relaxed = true)
    every { context.resources.displayMetrics.densityDpi } returns 450

    // pass in mocked context
    assertEquals(IconHelper.getIconForDevice(context, "https://website.com/image.png"), "https://website.com/image-xxh.png")
}

更新

ClassCastException DisplayMetrics 第一:

val metrics = context.resources.displayMetrics

我想你得把这两个字分开 displayMetrics 和 密度dpi :

@Test
fun getIconForDevice_ReturnsUrlWithXxhForXxhDisplay() {
  val context: Context = mockk(relaxed = true)
  val displayMetrics: DisplayMetrics = mockk(relaxed = true) // maybe relaxed is not needed, I just put it here in case
  every { context.resources.displayMetrics } returns displayMetrics
  every { displayMetrics.densityDpi } returns 450

  assertEquals(IconHelper.getIconForDevice(context, "https://website.com/image.png"), "https://website.com/image-xxh.png")
}