2 files changed, 22 insertions, 21 deletions

diff --git a/container-core/src/main/java/com/yahoo/container/jdisc/state/StateMonitor.java b/container-core/src/main/java/com/yahoo/container/jdisc/state/StateMonitor.java
index 6ccd25ad6c7..a5be5cb0b0a 100644
--- a/container-core/src/main/java/com/yahoo/container/jdisc/state/StateMonitor.java
+++ b/container-core/src/main/java/com/yahoo/container/jdisc/state/StateMonitor.java
@@ -11,6 +11,7 @@ import com.yahoo.log.LogLevel;
 import java.util.Map;
 import java.util.TreeSet;
 import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.TimeUnit;
 import java.util.logging.Logger;
 
@@ -38,12 +39,19 @@ public class StateMonitor extends AbstractComponent {
 
     @Inject
     public StateMonitor(HealthMonitorConfig config, Timer timer) {
+        this(config, timer, runnable -> {
+            Thread thread = new Thread(runnable, "StateMonitor");
+            thread.setDaemon(true);
+            return thread;
+        });
+    }
+
+    StateMonitor(HealthMonitorConfig config, Timer timer, ThreadFactory threadFactory) {
         this.timer = timer;
         this.snapshotIntervalMs = (long)(config.snapshot_interval() * TimeUnit.SECONDS.toMillis(1));
         this.lastSnapshotTimeMs = timer.currentTimeMillis();
         this.status = Status.valueOf(config.initialStatus());
-        thread = new Thread(StateMonitor.this::run, "StateMonitor");
-        thread.setDaemon(true);
+        thread = threadFactory.newThread(this::run);
         thread.start();
     }
 
@@ -69,6 +77,7 @@ public class StateMonitor extends AbstractComponent {
     /** Returns the interval between each metrics snapshot used by this */
     public long getSnapshotIntervalMillis() { return snapshotIntervalMs; }
 
+    /** NOTE: For unit testing only. May lead to undefined behaviour if StateMonitor thread is running simultaneously **/
     boolean checkTime() {
         long now = timer.currentTimeMillis();
         if (now < lastSnapshotTimeMs + snapshotIntervalMs) {
diff --git a/container-core/src/test/java/com/yahoo/container/jdisc/state/StateHandlerTest.java b/container-core/src/test/java/com/yahoo/container/jdisc/state/StateHandlerTest.java
index 5d8f885f8d0..a4c993f8c39 100644
--- a/container-core/src/test/java/com/yahoo/container/jdisc/state/StateHandlerTest.java
+++ b/container-core/src/test/java/com/yahoo/container/jdisc/state/StateHandlerTest.java
@@ -29,6 +29,7 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.TreeMap;
+import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicLong;
 
@@ -36,6 +37,7 @@ import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.mock;
 
 /**
  * @author Simon Thoresen Hult
@@ -51,30 +53,20 @@ public class StateHandlerTest {
 
     @Before
     public void startTestDriver() {
-        driver = TestDriver.newSimpleApplicationInstanceWithoutOsgi(new AbstractModule() {
-
+        Timer timer = this.currentTimeMillis::get;
+        this.driver = TestDriver.newSimpleApplicationInstanceWithoutOsgi(new AbstractModule() {
             @Override
             protected void configure() {
-                bind(Timer.class).toInstance(new Timer() {
-
-                    @Override
-                    public long currentTimeMillis() {
-                        return currentTimeMillis.get();
-                    }
-                });
+                bind(Timer.class).toInstance(timer);
             }
         });
         ContainerBuilder builder = driver.newContainerBuilder();
-        builder.guiceModules().install(new AbstractModule() {
-
-            @Override
-            protected void configure() {
-                bind(HealthMonitorConfig.class)
-                        .toInstance(new HealthMonitorConfig(new HealthMonitorConfig.Builder().snapshot_interval(
-                                TimeUnit.MILLISECONDS.toSeconds(SNAPSHOT_INTERVAL))));
-            }
-        });
-        monitor = builder.guiceModules().getInstance(StateMonitor.class);
+        HealthMonitorConfig healthMonitorConfig =
+                new HealthMonitorConfig(
+                        new HealthMonitorConfig.Builder()
+                                .snapshot_interval(TimeUnit.MILLISECONDS.toSeconds(SNAPSHOT_INTERVAL)));
+        ThreadFactory threadFactory = ignored -> mock(Thread.class);
+        this.monitor = new StateMonitor(healthMonitorConfig, timer, threadFactory);
         builder.guiceModules().install(new AbstractModule() {
 
             @Override