断言按钮颜色是可组合的 MaterialTheme.colors.primary

Question

我有一个简单的按钮。它的颜色集是根据条件设置的，我想测试从 MaterialTheme 应用了正确的颜色，但测试失败说 @Compos

@Composable
fun Btn(shopState: Int) {
    //set color based on the state now, default being primary
    var color = MaterialTheme.colors.primary
     if (shopState == 2) {...}
     else if (shopState == 3) {...}
    Button(onClick = {
        /*
         call calculation method passing the current value of shopState
        */
    }) {
        Text(text = "Calculate", color = color)
    }
}

现在测试文件（从 SO 复制）：

fun SemanticsNodeInteraction.assertButtonColor(expectedColor: Color) {
    val capturedName = captureToImage().colorSpace.name
    assertEquals(expectedColor.colorSpace.name, capturedName)
}

但是当我这样做时：

composeTestRule.onNodeWithText("Calculate").assertButtonColor(MaterialTheme.colors.primary)

它不会在 MaterialTheme 的颜色属性下以红线运行：@Composable 调用只能发生在@Composables 中。

如何断言当前应用了 MaterialTheme.colors.primary？

Answer 1

你可以使用类似的东西：

    var onPrimary = Color.Transparent
    var content = Color.Transparent
    rule.setMaterialContent {
        onPrimary = MaterialTheme.colors.onPrimary
        Button(onClick = {}) {
            content = LocalContentColor.current
        }
    }

    assertThat(content).isEqualTo(onPrimary)