Fixes failing CustomizationProviderTest.

The issue was the recent introduction of runBlocking { } calls in
ag/21396218. These block the logic on the current thread, causing unit
test runners to choke. Instead, we should use
runBlocking(CoroutineDispatcher) { } to make sure that the suspend
function yields back to the running test.

In addition to that change, we also needed to move the test onto an
UnconfinedTestDispatcher.

Fix: 269679515
Test: tests pass locally with atest
Change-Id: Iff661303af8791df7751fac7788681a105d47a75

packages/SystemUI/src/com/android/systemui/keyguard/CustomizationProvider.kt

@@ -131,7 +131,7 @@ class CustomizationProvider :
             throw UnsupportedOperationException()
         }
 
-        return runBlocking { insertSelection(values) }
+        return runBlocking(mainDispatcher) { insertSelection(values) }
     }
 
     override fun query(
@@ -171,7 +171,7 @@ class CustomizationProvider :
             throw UnsupportedOperationException()
         }
 
-        return runBlocking { deleteSelection(uri, selectionArgs) }
+        return runBlocking(mainDispatcher) { deleteSelection(uri, selectionArgs) }
     }
 
     override fun call(method: String, arg: String?, extras: Bundle?): Bundle? {

packages/SystemUI/tests/src/com/android/systemui/keyguard/CustomizationProviderTest.kt

@@ -62,7 +62,6 @@ import com.android.systemui.util.mockito.whenever
 import com.android.systemui.util.settings.FakeSettings
 import com.google.common.truth.Truth.assertThat
 import kotlinx.coroutines.ExperimentalCoroutinesApi
-import kotlinx.coroutines.test.StandardTestDispatcher
 import kotlinx.coroutines.test.TestScope
 import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import kotlinx.coroutines.test.runTest
@@ -104,7 +103,7 @@ class CustomizationProviderTest : SysuiTestCase() {
         whenever(backgroundHandler.looper).thenReturn(TestableLooper.get(this).looper)
 
         underTest = CustomizationProvider()
-        val testDispatcher = StandardTestDispatcher()
+        val testDispatcher = UnconfinedTestDispatcher()
         testScope = TestScope(testDispatcher)
         val localUserSelectionManager =
             KeyguardQuickAffordanceLocalUserSelectionManager(