Fail scan request if no channels are available

This fails scan request if no available channels could
be scanned for this request.
With this fix we can avoid the freezing of WifiScanner in
aformentioned case.

Bug: 67015387
Test: compile, unit test, integration test
Change-Id: I68654ce8d53104484c1559d8b0525585ab50b9e5

1 files changed, 34 insertions, 0 deletions

diff --git a/tests/wifitests/src/com/android/server/wifi/scanner/WificondScannerTest.java b/tests/wifitests/src/com/android/server/wifi/scanner/WificondScannerTest.java
index ed7c58298..d337cf1cf 100644
--- a/tests/wifitests/src/com/android/server/wifi/scanner/WificondScannerTest.java
+++ b/tests/wifitests/src/com/android/server/wifi/scanner/WificondScannerTest.java
@@ -32,6 +32,7 @@ import com.android.server.wifi.ScanDetail;
 import com.android.server.wifi.ScanResults;
 import com.android.server.wifi.WifiMonitor;
 import com.android.server.wifi.WifiNative;
+import com.android.server.wifi.scanner.ChannelHelper.ChannelCollection;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -56,6 +57,39 @@ public class WificondScannerTest extends BaseWifiScannerImplTest {
                 mLooper.getLooper(), mClock);
     }
 
+    /**
+     * Test that WificondScannerImpl will not issue a scan and report scan failure
+     * when there is no channel to scan for.
+     */
+    @Test
+    public void singleScanNotIssuedIfNoAvailableChannels() {
+        // Use mocked ChannelHelper and ChannelCollection to simulate the scenario
+        // that no channel is available for this request.
+        ChannelHelper channelHelper = mock(ChannelHelper.class);
+        ChannelCollection channelCollection = mock(ChannelCollection.class);
+        when(channelHelper.createChannelCollection()).thenReturn(channelCollection);
+        when(channelCollection.isEmpty()).thenReturn(true);
+
+        mScanner = new WificondScannerImpl(mContext, mWifiNative, mWifiMonitor,
+                channelHelper, mLooper.getLooper(), mClock);
+
+        WifiNative.ScanSettings settings = new NativeScanSettingsBuilder()
+                .withBasePeriod(10000) // ms
+                .withMaxApPerScan(10)
+                .addBucketWithBand(10000 /* ms */, WifiScanner.REPORT_EVENT_AFTER_EACH_SCAN,
+                        WifiScanner.WIFI_BAND_5_GHZ)
+                .build();
+        WifiNative.ScanEventHandler eventHandler = mock(WifiNative.ScanEventHandler.class);
+        mScanner.startSingleScan(settings, eventHandler);
+
+        mLooper.dispatchAll();
+
+        // No scan is issued to WifiNative.
+        verify(mWifiNative, never()).scan(any(), any(Set.class));
+        // A scan failed event must be reported.
+        verify(eventHandler).onScanStatus(WifiNative.WIFI_SCAN_FAILED);
+    }
+
     @Test
     public void backgroundScanSuccessSingleBucket() {
         WifiNative.ScanSettings settings = new NativeScanSettingsBuilder()