Fixing minor issue in detection logic of Resource Availability detector (#45)

* Fixing minor issue in detection logic of Resource Availability detector

* Adding unit tests

src/main/java/com/microsoft/dhalion/detectors/ResourceAvailabilityDetector.java

@@ -56,7 +56,7 @@ public abstract class ResourceAvailabilityDetector extends Detector {
   @Override
   public Collection<Symptom> detect(Collection<Measurement> measurements) {
     Instant now = context.checkpoint();
-    Instant previous = context.checkpoint();
+    Instant previous = context.previousCheckpoint();
 
     MeasurementsTable filteredMeasurements = context.measurements().between(previous, now);
     if (filteredMeasurements.size() == 0) {

src/test/java/com/microsoft/dhalion/detectors/ExcessCpuDetectorTest.java

@@ -0,0 +1,130 @@
+/*
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ *
+ * This program is made available under the terms of the MIT License.
+ * See the LICENSE file in the project root for more information.
+ */
+
+package com.microsoft.dhalion.detectors;
+
+import com.microsoft.dhalion.api.IDetector;
+import com.microsoft.dhalion.conf.PolicyConfig;
+import com.microsoft.dhalion.core.Measurement;
+import com.microsoft.dhalion.core.MeasurementsTable;
+import com.microsoft.dhalion.core.Symptom;
+import com.microsoft.dhalion.core.SymptomsTable;
+import com.microsoft.dhalion.policy.PoliciesExecutor.ExecutionContext;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.time.Instant;
+import java.time.temporal.ChronoUnit;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+
+import static com.microsoft.dhalion.detectors.ResourceAvailabilityDetector.DEMAND_METRIC_NAME_KEY;
+import static com.microsoft.dhalion.detectors.ResourceAvailabilityDetector.FREE_METRIC_NAME_KEY;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class ExcessCpuDetectorTest {
+  private ExecutionContext context;
+
+  private IDetector detector;
+  private PolicyConfig policyConf;
+  private Collection<Measurement> metrics;
+  private Collection<Measurement> metrics2;
+
+  private static final String FREE_METRIC = "free_metric";
+  private static final String DEMAND_METRIC = "demand_metric";
+
+  @Before
+  public void initialize() {
+    Instant currentInstant = Instant.now();
+    Instant previousInstant = currentInstant.minus(1, ChronoUnit.MINUTES);
+    context = mock(ExecutionContext.class);
+    when(context.checkpoint()).thenReturn(currentInstant);
+    when(context.previousCheckpoint()).thenReturn(previousInstant);
+
+    HashMap<String, Object> conf = new HashMap<>();
+    conf.put(ExcessCpuDetector.class.getSimpleName() + FREE_METRIC_NAME_KEY,
+        FREE_METRIC);
+    conf.put(ExcessCpuDetector.class.getSimpleName() + DEMAND_METRIC_NAME_KEY,
+        DEMAND_METRIC);
+    policyConf = new PolicyConfig(null, conf);
+
+    Instant metricInstant = currentInstant.minus(30, ChronoUnit.SECONDS);
+
+    Measurement instance1 = new Measurement("c1", "i1", FREE_METRIC, metricInstant, 10);
+    Measurement instance2 = new Measurement("c2", "i2", FREE_METRIC, metricInstant, 91);
+    Measurement instance3 = new Measurement("c3", "i3", FREE_METRIC, metricInstant, 50);
+    Measurement instance4 = new Measurement("c4", "i4", FREE_METRIC, metricInstant, 60);
+    Measurement instance5 = new Measurement("c5", "i1", DEMAND_METRIC, metricInstant, 25);
+    Measurement instance6 = new Measurement("c6", "i2", DEMAND_METRIC, metricInstant, 20);
+    Measurement instance7 = new Measurement("c7", "i3", DEMAND_METRIC, metricInstant, 29);
+    Measurement instance8 = new Measurement("c8", "i4", DEMAND_METRIC, metricInstant, 10);
+
+    metricInstant = previousInstant.minus(30, ChronoUnit.SECONDS);
+    Measurement instance9 = new Measurement("c1", "i1", FREE_METRIC, metricInstant, 10);
+    Measurement instance10 = new Measurement("c2", "i2", FREE_METRIC, metricInstant, 91);
+    Measurement instance11 = new Measurement("c3", "i3", FREE_METRIC, metricInstant, 50);
+    Measurement instance12 = new Measurement("c4", "i4", FREE_METRIC, metricInstant, 60);
+    Measurement instance13 = new Measurement("c5", "i1", DEMAND_METRIC, metricInstant, 25);
+    Measurement instance14 = new Measurement("c6", "i2", DEMAND_METRIC, metricInstant, 20);
+    Measurement instance15 = new Measurement("c7", "i3", DEMAND_METRIC, metricInstant, 29);
+    Measurement instance16 = new Measurement("c8", "i4", DEMAND_METRIC, metricInstant, 10);
+
+    metrics = new ArrayList<>();
+    metrics.add(instance1);
+    metrics.add(instance2);
+    metrics.add(instance3);
+    metrics.add(instance4);
+    metrics.add(instance5);
+    metrics.add(instance6);
+    metrics.add(instance7);
+    metrics.add(instance8);
+
+    metrics2 = new ArrayList<>();
+    metrics2.add(instance9);
+    metrics2.add(instance10);
+    metrics2.add(instance11);
+    metrics2.add(instance12);
+    metrics2.add(instance13);
+    metrics2.add(instance14);
+    metrics2.add(instance15);
+    metrics2.add(instance16);
+  }
+
+  @Test
+  public void testDetectorWithMetricsInRange() {
+    when(context.measurements()).thenReturn(MeasurementsTable.of(metrics));
+
+    detector = new ExcessCpuDetector(policyConf);
+    detector.initialize(context);
+
+    Collection<Symptom> symptoms = detector.detect(metrics);
+    SymptomsTable symptomsTable = SymptomsTable.of(symptoms);
+
+    assertEquals(2, symptomsTable.size());
+    assertTrue(symptomsTable.type(SymptomName.EXCESS_CPU.text())
+        .assignment("i2").size() > 0);
+    assertTrue(symptomsTable.type(SymptomName.EXCESS_CPU.text())
+        .assignment("i4").size() > 0);
+  }
+
+  @Test
+  public void testDetectorWhenMetricsOutOfRange() {
+    when(context.measurements()).thenReturn(MeasurementsTable.of(metrics2));
+
+    detector = new ExcessCpuDetector(policyConf);
+    detector.initialize(context);
+
+    Collection<Symptom> symptoms = detector.detect(metrics);
+    SymptomsTable symptomsTable = SymptomsTable.of(symptoms);
+
+    assertEquals(0, symptomsTable.size());
+  }
+}

src/test/java/com/microsoft/dhalion/detectors/ExcessMemoryDetectorTest.java

@@ -0,0 +1,130 @@
+/*
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ *
+ * This program is made available under the terms of the MIT License.
+ * See the LICENSE file in the project root for more information.
+ */
+
+package com.microsoft.dhalion.detectors;
+
+import com.microsoft.dhalion.api.IDetector;
+import com.microsoft.dhalion.conf.PolicyConfig;
+import com.microsoft.dhalion.core.Measurement;
+import com.microsoft.dhalion.core.MeasurementsTable;
+import com.microsoft.dhalion.core.Symptom;
+import com.microsoft.dhalion.core.SymptomsTable;
+import com.microsoft.dhalion.policy.PoliciesExecutor.ExecutionContext;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.time.Instant;
+import java.time.temporal.ChronoUnit;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+
+import static com.microsoft.dhalion.detectors.ResourceAvailabilityDetector.DEMAND_METRIC_NAME_KEY;
+import static com.microsoft.dhalion.detectors.ResourceAvailabilityDetector.FREE_METRIC_NAME_KEY;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class ExcessMemoryDetectorTest {
+  private ExecutionContext context;
+
+  private IDetector detector;
+  private PolicyConfig policyConf;
+  private Collection<Measurement> metrics;
+  private Collection<Measurement> metrics2;
+
+  private static final String FREE_METRIC = "free_metric";
+  private static final String DEMAND_METRIC = "demand_metric";
+
+  @Before
+  public void initialize() {
+    Instant currentInstant = Instant.now();
+    Instant previousInstant = currentInstant.minus(1, ChronoUnit.MINUTES);
+    context = mock(ExecutionContext.class);
+    when(context.checkpoint()).thenReturn(currentInstant);
+    when(context.previousCheckpoint()).thenReturn(previousInstant);
+
+    HashMap<String, Object> conf = new HashMap<>();
+    conf.put(ExcessMemoryDetector.class.getSimpleName() + FREE_METRIC_NAME_KEY,
+        FREE_METRIC);
+    conf.put(ExcessMemoryDetector.class.getSimpleName() + DEMAND_METRIC_NAME_KEY,
+        DEMAND_METRIC);
+    policyConf = new PolicyConfig(null, conf);
+
+    Instant metricInstant = currentInstant.minus(30, ChronoUnit.SECONDS);
+
+    Measurement instance1 = new Measurement("c1", "i1", FREE_METRIC, metricInstant, 10);
+    Measurement instance2 = new Measurement("c2", "i2", FREE_METRIC, metricInstant, 91);
+    Measurement instance3 = new Measurement("c3", "i3", FREE_METRIC, metricInstant, 50);
+    Measurement instance4 = new Measurement("c4", "i4", FREE_METRIC, metricInstant, 60);
+    Measurement instance5 = new Measurement("c5", "i1", DEMAND_METRIC, metricInstant, 25);
+    Measurement instance6 = new Measurement("c6", "i2", DEMAND_METRIC, metricInstant, 20);
+    Measurement instance7 = new Measurement("c7", "i3", DEMAND_METRIC, metricInstant, 29);
+    Measurement instance8 = new Measurement("c8", "i4", DEMAND_METRIC, metricInstant, 10);
+
+    metricInstant = previousInstant.minus(30, ChronoUnit.SECONDS);
+    Measurement instance9 = new Measurement("c1", "i1", FREE_METRIC, metricInstant, 10);
+    Measurement instance10 = new Measurement("c2", "i2", FREE_METRIC, metricInstant, 91);
+    Measurement instance11 = new Measurement("c3", "i3", FREE_METRIC, metricInstant, 50);
+    Measurement instance12 = new Measurement("c4", "i4", FREE_METRIC, metricInstant, 60);
+    Measurement instance13 = new Measurement("c5", "i1", DEMAND_METRIC, metricInstant, 25);
+    Measurement instance14 = new Measurement("c6", "i2", DEMAND_METRIC, metricInstant, 20);
+    Measurement instance15 = new Measurement("c7", "i3", DEMAND_METRIC, metricInstant, 29);
+    Measurement instance16 = new Measurement("c8", "i4", DEMAND_METRIC, metricInstant, 10);
+
+    metrics = new ArrayList<>();
+    metrics.add(instance1);
+    metrics.add(instance2);
+    metrics.add(instance3);
+    metrics.add(instance4);
+    metrics.add(instance5);
+    metrics.add(instance6);
+    metrics.add(instance7);
+    metrics.add(instance8);
+
+    metrics2 = new ArrayList<>();
+    metrics2.add(instance9);
+    metrics2.add(instance10);
+    metrics2.add(instance11);
+    metrics2.add(instance12);
+    metrics2.add(instance13);
+    metrics2.add(instance14);
+    metrics2.add(instance15);
+    metrics2.add(instance16);
+  }
+
+  @Test
+  public void testDetectorWithMetricsInRange() {
+    when(context.measurements()).thenReturn(MeasurementsTable.of(metrics));
+
+    detector = new ExcessMemoryDetector(policyConf);
+    detector.initialize(context);
+
+    Collection<Symptom> symptoms = detector.detect(metrics);
+    SymptomsTable symptomsTable = SymptomsTable.of(symptoms);
+
+    assertEquals(2, symptomsTable.size());
+    assertTrue(symptomsTable.type(SymptomName.EXCESS_MEMORY.text())
+        .assignment("i2").size() > 0);
+    assertTrue(symptomsTable.type(SymptomName.EXCESS_MEMORY.text())
+        .assignment("i4").size() > 0);
+  }
+
+  @Test
+  public void testDetectorWhenMetricsOutOfRange() {
+    when(context.measurements()).thenReturn(MeasurementsTable.of(metrics2));
+
+    detector = new ExcessMemoryDetector(policyConf);
+    detector.initialize(context);
+
+    Collection<Symptom> symptoms = detector.detect(metrics);
+    SymptomsTable symptomsTable = SymptomsTable.of(symptoms);
+
+    assertEquals(0, symptomsTable.size());
+  }
+}