Restore equals and hashcode on MetricKeyPair

That is being used by tests if you want to make sure that the dao is
being called with the correct number of parameters.

Author: Michael Kunze

build.gradle.kts

@@ -12,7 +12,7 @@ plugins {
 }
 
 group = "de.inoxio"
-version = "1.0.0"
+version = "1.0.1"
 description = "A java-spring library to push metrics to cloudwatch"
 
 apply {
@@ -32,6 +32,7 @@ dependencies {
     // test
     testImplementation("org.springframework.boot:spring-boot-starter-test")
     testImplementation("org.mockito:mockito-core:2.23.0")
+    testImplementation("nl.jqno.equalsverifier:equalsverifier:3.0")
 }
 
 java {

src/main/java/de/inoxio/spring/cloudwatchmetrics/MetricKeyPair.java

@@ -1,6 +1,8 @@
 package de.inoxio.spring.cloudwatchmetrics;
 
-public class MetricKeyPair {
+import java.util.Objects;
+
+public final class MetricKeyPair {
 
     private final String name;
     private final double value;
@@ -18,6 +20,30 @@ public double getValue() {
         return value;
     }
 
+    @Override
+    public boolean equals(final Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+
+        final var that = (MetricKeyPair) o;
+
+        return Double.compare(that.value, value) == 0 && Objects.equals(name, that.name);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(name, value);
+    }
+
+    @Override
+    public String toString() {
+        return "MetricKeyPair{" + "name='" + name + '\'' + ", value=" + value + '}';
+    }
+
     public static final class MetricKeyPairBuilder {
 
         private String name;

src/test/java/de/inoxio/spring/cloudwatchmetrics/MetricKeyPairTest.java

@@ -0,0 +1,32 @@
+package de.inoxio.spring.cloudwatchmetrics;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+
+import static de.inoxio.spring.cloudwatchmetrics.MetricKeyPair.MetricKeyPairBuilder.metricKeyPairBuilder;
+
+import org.junit.Test;
+
+import nl.jqno.equalsverifier.EqualsVerifier;
+
+public class MetricKeyPairTest {
+
+    @Test
+    public void shouldTestEqualsAndHashcode() {
+        EqualsVerifier.forClass(MetricKeyPair.class).verify();
+    }
+
+    @Test
+    public void shouldConvertObjectToString() {
+
+        // given
+        final var metricKeyPair = metricKeyPairBuilder().name("name").value(1.0).build();
+
+        // when
+        final var toString = metricKeyPair.toString();
+
+        // then
+        assertThat(toString, is("MetricKeyPair{name='name', value=1.0}"));
+    }
+
+}