diff --git a/metrics/pom.xml b/metrics/pom.xml
index 86f197240b..9cf1ec588f 100644
--- a/metrics/pom.xml
+++ b/metrics/pom.xml
@@ -84,6 +84,13 @@
             <artifactId>spectator-api</artifactId>
             <version>${spectator-api.version}</version>
         </dependency>
+        
+		<dependency>
+		    <groupId>org.assertj</groupId>
+		    <artifactId>assertj-core</artifactId>
+		    <scope>test</scope>
+		</dependency>
+        
     </dependencies>
 
     <dependencyManagement>
diff --git a/metrics/src/test/java/com/baeldung/metrics/micrometer/MicrometerAtlasIntegrationTest.java b/metrics/src/test/java/com/baeldung/metrics/micrometer/MicrometerAtlasIntegrationTest.java
index e7f3d7ec72..689e23ad6d 100644
--- a/metrics/src/test/java/com/baeldung/metrics/micrometer/MicrometerAtlasIntegrationTest.java
+++ b/metrics/src/test/java/com/baeldung/metrics/micrometer/MicrometerAtlasIntegrationTest.java
@@ -1,8 +1,12 @@
 package com.baeldung.metrics.micrometer;
 
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.within;
+import static org.assertj.core.api.Assertions.withinPercentage;
 import static org.hamcrest.CoreMatchers.allOf;
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.collection.IsMapContaining.hasEntry;
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 import io.micrometer.atlas.AtlasMeterRegistry;
@@ -31,8 +35,10 @@ import java.util.Optional;
 import java.util.concurrent.TimeUnit;
 import java.util.stream.Collectors;
 
+import org.assertj.core.data.Percentage;
 import org.junit.Before;
 import org.junit.Test;
+import org.junit.jupiter.api.Assertions;
 
 import com.netflix.spectator.atlas.AtlasConfig;
 
@@ -156,7 +162,8 @@ public class MicrometerAtlasIntegrationTest {
         timer.record(30, TimeUnit.MILLISECONDS);
 
         assertTrue(2 == timer.count());
-        assertTrue(50 > timer.totalTime(TimeUnit.MILLISECONDS) && 45 <= timer.totalTime(TimeUnit.MILLISECONDS));
+        
+        assertThat(timer.totalTime(TimeUnit.MILLISECONDS)).isBetween(40.0, 55.0);
     }
 
     @Test
@@ -173,7 +180,7 @@ public class MicrometerAtlasIntegrationTest {
         }
         long timeElapsed = longTaskTimer.stop(currentTaskId);
 
-        assertTrue(timeElapsed / (int) 1e6 == 2);
+        assertEquals(2L, timeElapsed/((int) 1e6),1L);
     }
 
     @Test
diff --git a/metrics/src/test/java/com/baeldung/metrics/servo/AtlasObserverLiveTest.java b/metrics/src/test/java/com/baeldung/metrics/servo/AtlasObserverLiveTest.java
index 134c3c91cf..b8a5b93e49 100644
--- a/metrics/src/test/java/com/baeldung/metrics/servo/AtlasObserverLiveTest.java
+++ b/metrics/src/test/java/com/baeldung/metrics/servo/AtlasObserverLiveTest.java
@@ -27,6 +27,9 @@ import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.CoreMatchers.not;
 import static org.junit.Assert.assertThat;
 
+/**
+ * Atlas server needs to be up and running for this live test to work.
+ */
 public class AtlasObserverLiveTest {
 
     private final String atlasUri = "http://localhost:7101/api/v1";
diff --git a/metrics/src/test/java/com/baeldung/metrics/servo/MetricTypeManualTest.java b/metrics/src/test/java/com/baeldung/metrics/servo/MetricTypeManualTest.java
index d810de155a..92bbd615b9 100644
--- a/metrics/src/test/java/com/baeldung/metrics/servo/MetricTypeManualTest.java
+++ b/metrics/src/test/java/com/baeldung/metrics/servo/MetricTypeManualTest.java
@@ -109,20 +109,20 @@ public class MetricTypeManualTest {
             .build(), MILLISECONDS);
 
         Stopwatch stopwatch = timer.start();
-        MILLISECONDS.sleep(1);
-        timer.record(2, MILLISECONDS);
+        SECONDS.sleep(1);
+        timer.record(2, SECONDS);
         stopwatch.stop();
 
-        assertEquals("timer should count 1 millisecond", 1, timer
+        assertEquals("timer should count 1 second", 1000, timer
           .getValue()
-          .intValue());
-        assertEquals("timer should count 3 millisecond in total", 3, timer.getTotalTime()
-            .intValue());
+          .intValue(),1000);        
+        assertEquals("timer should count 3 second in total", 3000, timer.getTotalTime()
+            .intValue(),1000);
         assertEquals("timer should record 2 updates", 2, timer
           .getCount()
           .intValue());
 
-        assertEquals("timer should have max 2", 2, timer.getMax(), 0.01);
+        assertEquals("timer should have max 2", 2000, timer.getMax(), 0.01);
     }
 
     @Test
@@ -161,7 +161,6 @@ public class MetricTypeManualTest {
     }
 
     @Test
-    //==
     public void givenStatsTimer_whenExecuteTask_thenStatsCalculated() throws Exception {
         System.setProperty("netflix.servo", "1000");
         StatsTimer timer = new StatsTimer(MonitorConfig
@@ -178,21 +177,21 @@ public class MetricTypeManualTest {
             .build(), MILLISECONDS);
 
         Stopwatch stopwatch = timer.start();
-        MILLISECONDS.sleep(1);
-        timer.record(3, MILLISECONDS);
+        SECONDS.sleep(1);
+        timer.record(3, SECONDS);
         stopwatch.stop();
 
         stopwatch = timer.start();
-        timer.record(6, MILLISECONDS);
-        MILLISECONDS.sleep(2);
+        timer.record(6, SECONDS);
+        SECONDS.sleep(2);
         stopwatch.stop();
 
-        assertEquals("timer should count 12 milliseconds in total", 12, timer.getTotalTime());
-        assertEquals("timer should count 12 milliseconds in total", 12, timer.getTotalMeasurement());
+        assertEquals("timer should count 12 seconds in total", 12000, timer.getTotalTime(),500);
+        assertEquals("timer should count 12 seconds in total", 12000, timer.getTotalMeasurement(),500);
         assertEquals("timer should record 4 updates", 4, timer.getCount());
-        assertEquals("stats timer value time-cost/update should be 2", 3, timer
+        assertEquals("stats timer value time-cost/update should be 2", 3000, timer
           .getValue()
-          .intValue());
+          .intValue(),500);
 
         final Map<String, Number> metricMap = timer
           .getMonitors()
@@ -235,4 +234,4 @@ public class MetricTypeManualTest {
         assertEquals("information collected", informational.getValue());
     }
 
-}
+}
\ No newline at end of file