Add CTS test for getSupplementalProcessPackageName()

Bug: 215241564
Test: atest PackageManagerShellCommandTest
Change-Id: I99840640ac018fe73dbafe533ee9f250c041788d
diff --git a/tests/tests/content/src/android/content/pm/cts/PackageManagerShellCommandTest.java b/tests/tests/content/src/android/content/pm/cts/PackageManagerShellCommandTest.java
index ec96a60..f4a482d 100644
--- a/tests/tests/content/src/android/content/pm/cts/PackageManagerShellCommandTest.java
+++ b/tests/tests/content/src/android/content/pm/cts/PackageManagerShellCommandTest.java
@@ -1474,6 +1474,17 @@
         assertTrue(broadcastReceiverForCurrentUser.isBroadcastReceived());
     }
 
+    @Test
+    public void testQuerySupplementalProcessPackageName() throws Exception {
+        final PackageManager pm = getPackageManager();
+        final String name = pm.getSupplementalProcessPackageName();
+        assertNotNull(name);
+        final ApplicationInfo info = pm.getApplicationInfo(
+                name, PackageManager.ApplicationInfoFlags.of(PackageManager.MATCH_SYSTEM_ONLY));
+        assertEquals(ApplicationInfo.FLAG_SYSTEM, info.flags & ApplicationInfo.FLAG_SYSTEM);
+        assertTrue(info.sourceDir.startsWith("/apex/com.android.supplementalprocess"));
+    }
+
     private static class FullyRemovedBroadcastReceiver extends BroadcastReceiver {
         private final String mTargetPackage;
         private final int mTargetUserId;