Fix back arrow in wifi settings "connect to this network connection qr code" does not work

When clicking back button, pop fragment and Finish the activity if there is nothing to pop

Bug: 132132756
Test: atest WifiDppConfiguratorActivityTest
Change-Id: Ia16951e79e578f1625e5fadd26553735fa90bffa

src/com/android/settings/wifi/dpp/WifiDppConfiguratorActivity.java

@@ -323,15 +323,10 @@ public class WifiDppConfiguratorActivity extends InstrumentedActivity implements
 
     @Override
     public boolean onNavigateUp() {
-        Fragment fragment = mFragmentManager.findFragmentById(R.id.fragment_container);
+        if (!mFragmentManager.popBackStackImmediate()) {
-        if (fragment instanceof WifiDppQrCodeGeneratorFragment) {
             finish();
-            return true;
-        } else if (fragment instanceof WifiDppQrCodeScannerFragment) {
-            mFragmentManager.popBackStackImmediate();
         }
-
+        return true;
-        return false;
     }
 
     @Override

tests/unit/src/com/android/settings/wifi/dpp/WifiDppConfiguratorActivityTest.java

@@ -175,4 +175,40 @@ public class WifiDppConfiguratorActivityTest {
         assertThat(restoredWifiNetworkConfig.getNetworkId()).isEqualTo(0);
         assertThat(restoredWifiNetworkConfig.isHotspot()).isTrue();
     }
+
+    @Test
+    public void launchScanner_onNavigateUp_shouldFinish() {
+        Intent intent = new Intent(WifiDppConfiguratorActivity.ACTION_CONFIGURATOR_QR_CODE_SCANNER);
+        intent.putExtra(WifiDppUtils.EXTRA_WIFI_SECURITY, "WEP");
+        intent.putExtra(WifiDppUtils.EXTRA_WIFI_SSID, "GoogleGuest");
+        intent.putExtra(WifiDppUtils.EXTRA_WIFI_PRE_SHARED_KEY, "password");
+        final Instrumentation instrumentation = InstrumentationRegistry.getInstrumentation();
+
+        mActivityRule.launchActivity(intent);
+
+        instrumentation.runOnMainSync(() -> {
+            mActivityRule.getActivity().onNavigateUp();
+
+            assertThat(mActivityRule.getActivity().isFinishing()).isEqualTo(true);
+        });
+    }
+
+    @Test
+    public void launchGenerator_onNavigateUp_shouldFinish() {
+        Intent intent = new Intent(
+                WifiDppConfiguratorActivity.ACTION_CONFIGURATOR_QR_CODE_GENERATOR);
+        intent.putExtra(WifiDppUtils.EXTRA_WIFI_SECURITY, "WEP");
+        intent.putExtra(WifiDppUtils.EXTRA_WIFI_SSID, "GoogleGuest");
+        intent.putExtra(WifiDppUtils.EXTRA_WIFI_PRE_SHARED_KEY, "password");
+        final Instrumentation instrumentation = InstrumentationRegistry.getInstrumentation();
+
+        mActivityRule.launchActivity(intent);
+
+        instrumentation.runOnMainSync(() -> {
+            mActivityRule.getActivity().onNavigateUp();
+
+            assertThat(mActivityRule.getActivity().isFinishing()).isEqualTo(true);
+        });
+    }
+
 }