Merge "Fixed NPE in FingerprintEnrollIntro" into main

src/com/android/settings/biometrics/fingerprint/FingerprintEnrollIntroduction.java

@@ -340,6 +340,9 @@ public class FingerprintEnrollIntroduction extends BiometricEnrollIntroduction {
             final List<FingerprintSensorPropertiesInternal> props =
                     mFingerprintManager.getSensorPropertiesInternal();
             // This will need to be updated for devices with multiple fingerprint sensors
+            if (props == null || props.isEmpty()) {
+                return R.string.fingerprint_intro_error_unknown;
+            }
             final int max = props.get(0).maxEnrollmentsPerUser;
             final int numEnrolledFingerprints =
                     mFingerprintManager.getEnrolledFingerprints(mUserId).size();

tests/robotests/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollIntroductionTest.java

@@ -252,6 +252,24 @@ public class FingerprintEnrollIntroductionTest {
         assertThat(result).isEqualTo(R.string.fingerprint_intro_error_max);
     }
 
+    @Test
+    public void intro_CheckNullPropsReturnsErrorString() {
+        setupFingerprintEnrollIntroWith(newTokenOnlyIntent());
+        when(mFingerprintManager.getSensorPropertiesInternal()).thenReturn(null);
+        final int result = mFingerprintEnrollIntroduction.checkMaxEnrolled();
+
+        assertThat(result).isEqualTo(R.string.fingerprint_intro_error_unknown);
+    }
+
+    @Test
+    public void intro_CheckEmptyPropsReturnsErrorString() {
+        setupFingerprintEnrollIntroWith(newTokenOnlyIntent());
+        when(mFingerprintManager.getSensorPropertiesInternal()).thenReturn(List.of());
+        final int result = mFingerprintEnrollIntroduction.checkMaxEnrolled();
+
+        assertThat(result).isEqualTo(R.string.fingerprint_intro_error_unknown);
+    }
+
     @Test
     public void intro_CheckGenerateChallenge() {
         setupFingerprintEnrollIntroWith(newGkPwHandleAndFromSettingsIntent());